Using an Indicator Model to Rank Relative Stock Status
Of Minor West Coast Rockfish Species
by
Stacey D. Miller
A PROJECT REPORT
Submitted To
Marine Resource Management
College of Oceanic and Atmospheric Sciences
Oregon State University
in partial fulfillment of
the requirements for the
degree of
Master of Science
Presented August 5, 2003
Commencement June 2004
ABSTRACT
Quantitative assessments of many West coast rockfish stocks of both major and
minor importance to commercial fisheries have shown varying declines in abundances.
The population sizes of less-abundant, co-occurring unassessed species may also be
declining. However, determining stock status of the many non-targeted, minor species
with high levels of certainty and quantifiable predictability may be prohibitively
expensive and/or impractical because of the dearth of available data. Using a system of
qualitative indicators may provide a cost-effective method to create preliminary
assessments of the relative status of minor rockfish stocks and subsequently prioritize
future studies. This project was undertaken to test a system of indicators to characterize
the status of West Coast rockfish species including Sebastes aurora, S. babcocki, S.
aleutianus, S. zacentrus, S. borealis, S. diploproa, and S. reedi.
An array of indicators including catch per unit effort, the proportion of positive
hauls, and length composition data were used to detect possible changes in the density,
distribution, and size composition of the population. Data were taken from three West
Coast bottom trawl surveys conducted by the National Marine Fisheries Service. The
percentage of trends indicating linear decline were summarized and stocks were
subsequently ranked in order of greatest concern over declining populations. S. babcocki
was ranked as the stock of greatest concern with 52% of the indices showing negative
trends while negative trends for S. diploproa, S. zacentrus, and S. borealis were found in
26%, 23%, and 20% of the indices, respectively. Less than 15% of determined trends
were negative for S. aleutianus, S. aurora, and S. reedi. Our interpretation of the health of
the population projected by the indicators was compared to the population status based
upon formal stock assessments for four species, S. alutus, S. crameri, S. melanostomus,
and S. rufus. Indicator-based assessments show potential to preliminarly assess numerous
species simultaneously and identify species of greatest concern over declining
populations.
ACKNOWLEDGEMENTS
This project and report would not have been possible without the contributions of
many people who have provided data, advice, support, and encouragement. Foremost, I
would like to thank my committee members, Gil Sylvia, Kevin Piner, Michael Schirripa,
and Selina Heppell, who have contributed to this project in very different yet significant
ways. Gil Sylvia for the guidance, mentoring, and encouragement during my graduate
studies and for always finding the time to discuss the complexities of fisheries
management. Kevin Piner for his knowledge, patience, and good humor. Michael
Schirripa for keeping me focused on my goals and Selina Heppell for her insight and
flexibility. A special thank you to David Sampson for his advice and support through out
the project.
I would also like to thank Bob Lauth, Mark Wilkins, and Will Daspit for
providing data for this analysis and special thanks to Tonya Ramsey for providing data
and so much more. Beth Horness was extremely helpful with database applications and
getting me started on this project. Appreciation is also extended to Clare Reimers,
Jessica Waddell, Todd Bridgeman and Waldo Wakefield for funding support and the rest
of the FRAM personnel who always made me feel at home.
Very special thanks to my fellow COAS students as well as Laurie Jodice, who
have enhanced my experience at OSU with insightful conversations, much laughter, and
friendships. Personal gratitude is extended to the Drouhards who have always reminded
me of the important things in life and to my family and friends back east who have
always encouraged me to pursue my dreams and taught me the value of perseverance.
Last but certainly not least, sincere gratitude is given to my husband, Chapell, whose
unconditional love and unfaltering faith made this voyage not only possible, but
bearable.
This project was funded by the Cooperative Institute for Marine Resource Studies
and the Fishery Resource Analysis and Monitoring Division of the Northwest Fisheries
Science Center, National Marine Fisheries Service under Grant number NA97FE0459.
TABLE OF CONTENTS
INTRODUCTION 1
BACKGROUND 7
U. S . FISHERY MANAGEMENT The Magnuson-Stevens Fishery Conservation and Management Act Status Determination Additional Statute Requirements Summary 7
7
10
11
12
A REGIONAL SCOPE: THE WEST COAST GROUNDFISH West Coast Groundfish Stock Status Slope Rockfish Assemblage 14
18
SUMMARY 19
METHODS THE INDICATOR ANALYSIS Pressure Indices State Indices DATA SOURCES Fishery Dependent Data Fishery Independent Data
STATISTICAL METHODS 13
20
20
20
22
25
25
25
29
TABLE OF CONTENTS (Continued)
RESULTS 30
PRESSURE-STATE INDICATORS General Trends: Pressure Indicators General Trends: State Indicators Summary of Indicator Results for Slope Rockfish Species RELATIVE RANKING OF CONCERN 30
30
35
37
42
DISCUSSION 46
PRESSURE-STATE INDICATORS 46
RESPONSE INDICATORS 48
General Management Implications Implications for West Coast Rockfish Management 48
49
THE INDICATOR MODEL 50
Model Caveats and Recommendations CONCLUSIONS 50
52
WORKS C11E,D 54
APPENDICES 60
APPENDIX A.
APPENDIX B.
APPENDIX C.
APPENDIX D.
APPENDIX E.
National Standards Comparison of Research Survey Data Sources. Commercial landings. Percent Co-Occurrence Tables. State Indicator Results. 61
62
64
71
78
LIST OF FIGURES
Figure 1. Status of US Stocks Figure 2. Mixed-Stock Fishery Exploitation Model 2
3
Figure 3. Pressure-State-Response Framework 6
Figure 4. West Coast Groundfish Stock Status 15
Figure 5. INPFC Statistical Areas 28
Figure 6. Commercial landings of major species 31
Figure 7. Commercial landings of minor species 32
Figure 8. Mean Percent Co-Occurrence. 33
Figure 9. Mean Percent Co-Occurrence. 34
LIST OF TABLES
Table 1. Overfished West Coast Groundfish 16
Table 2. Slope Rockfish Management Assemblages. 18
Table 3. Pressure-State Indicators 21
Table 4. Survey Strata. 27
Table 5. Summarized Results for "State" Indices 36
Table 6. Point values used in scoring trends and strata 42
Table 7. Relative ranking for species of concern 43
INTRODUCTION
One of the fundamental purposes of fisheries management is to ensure sustainable
production in the face of environmental variability (Salia and Gallucci 1996, Hilborn and
Waters 1992). While managing a single stock has often proved difficult, as exemplified
by the collapse of many fisheries worldwide, mixed-stock fisheries offer a bewildering
challenge to fishery resource managers particularly where the fishery is comprised of
targeted as well as non-targeted species. Although the targeted species may be
economically valuable, numerous non-targeted species have a wide variation in biomass
size but generally are of low economic value. Furthermore, species comprising mixedstock catch may have varying life history characteristics, and thereby are able to support
different levels of fishing mortality. The Organization for Economic Cooperation and
Development's Committee for Fisheries surveyed its member countries and found that
multi-species fisheries complicated all aspects of fishery management and a "high
proportion" of the multi-species fisheries included in their survey were performing badly
in terms of both conservation of the resources and economic performance (OECD 1997).
Fishery management in the United States is mandated to use the best scientific
information available. However, resources, including manpower, time, funds, and data
are inherently limited, and most fishery research and management efforts are focused on
the species comprising the majority of landings. In the United States, 259 of the 932
federally managed fish stocks account for 99.9% of total landings while the remaining
673 stocks account for only 0.1% of total landings (NMFS 2003). Consequently, little
information is typically available for stocks of minor importance to commercial or
recreational fisheries, hereafter referred to as "minor" stocks. Of the stocks of major
importance to the commercial or recreational fisheries hereafter referred to as "major"
stocks, the overfished status of 62% of the stocks is known, with 43 stocks classified as
overfished and 117 stocks not overfished. Currently, the overfished status of 99 major
stocks is unknown (NMFS 2003) (Figure 1).
4
Because evidence exists that many commercially important West coast rockfish stocks
are overfished, minor rockfish species comprising the multi-species assemblages may
also be at risk of being overfished.
Determining current and future stock status of the many non-targeted species with
high levels of certainty and quantifiable predictability may be prohibitively expensive
and impractical because of the dearth of available data. It may be reasonable, however,
to employ an array of indicators or meta-indicators to assess the relative health of a
population, and thus prioritize more in-depth assessments based on likely status. The use
of indicators to reveal information on the general health or status of a species or
ecosystem has been proposed as a basis for sustainable development (EEA 2003, CSD
2001) and in particular, fisheries management (Degnbol 2002, Nielsen and Degnbol
2001). A comprehensive set of indicators may lead to some knowledge of a system
without the exorbitant costs of traditional stock assessments based on hard, quantifiable
predictability (Degnbol 2002).
I propose that a set of indicators relating to the general health of non-targeted
species may provide scientists with a cost-effective knowledge base to prioritize species
for further comprehensive assessments and provide managers with some knowledge to
make informed decisions for federally managed fisheries of minor commercial or
recreational importance. A preliminary or qualitative assessment has been used in the
past to provide a description of the status of the species and the information base when
data is not available for a full statistical estimation of abundance. A qualitative
assessment does not provide information for quantitative implementation of harvest
policy, but instead may provide adequate means for discerning population trends that
may give an indication of the condition of the multi-species fishery. Welcomme (1999)
suggests that qualitative evaluations can provide an adequate indication of the health of
complex fisheries if traditional quantitative methods cannot be employed.
The use of sustainability indicators intended to inform fishery management
decisions is in its infancy, especially in industrial or developed countries. An exception
exists in the Northwest Atlantic where a set of indicators has been developed with
reference points such as fishing mortality, spawning stock biomass, and harvest control
rules (Nielsen and Degnbol 2001). The National Marine Fisheries Service, the federal
5
agency tasked with fishery management in the United States, has recommended the
development of ecosystem health indices as targets for management, however, has not
identified or suggested operational indices to be used (NMFS 1999). Conversely, much
of the work for developing and using suites of indices rather than complex assessments
has been with a focus on developing countries where the costs of data collection and
analysis necessary for complex assessments are not feasible, due to limited resources.
Indicators are defined as "quantitative or qualitative values, variables, pointers or
indices, or more generally, data or combination of data processed for a clearly defined
analytical or policy purpose" (FAO 1999, Le Gallic 2002). Indicators provide a practical
and cost-effective tool for describing and evaluating the state of fisheries resources and
the effects that policy changes have on those systems
Various indicator frameworks have been developed as a way to select and
organize criteria, indicators and reference points. The Pressure-State-Response (PSR)
framework (Figure 3), is one of the most common process frameworks. This model
considers the pressure imposed by human activities (fishing) on some aspect of the
system, the state of that aspect (stock status), and the actual or desired societal response
(FAO 1999, FAO 2001, Le Gallic 2002).
International institutions, such as the Organization for Economic
Cooperation and Development (OECD), the United Nations Food and Agriculture
Organization (FAO) and the Commission on Sustainable Development (CSD) have
suggested criteria and associated candidate indicators. Generally, criteria which are the
components of a reference system will: 1) have behavior that can be described via
indicators, proxy-indicators and reference points; 2) be observable by stakeholders; 3) be
understandable reflecting analytical soundness and substance; 4) be acceptable and
efficient; and 5) be related to management having associated reference values (FAO
1999, Degnbol 2001). A number of candidate methods and indicators referring to
pressure and state of fish stocks have been suggested, each requiring varying levels of
data and analysis. Examples of fishery-related "state and pressure" indicators include
maximum sustainable yield (MSY), catch per unit effort (CPUE), size composition, and
spawning stock biomass (SSB), a simple exerted effort index, or analytical estimation of
fishing mortality (F) (Degnbol 2001).
7
BACKGROUND
U.S. Fishery Management
Fisheries management is generally defined as a set of activities that are
implemented to achieve social objectives. In the United States, the primary objective of
fisheries management is the conservation and management of fishery resources based on
the best scientific information to prevent overfishing and assure optimum yield, where
"optimum" refers to the greatest overall benefit to the Nation. The management of U.S.
fishery resources is guided by the principal legislation, the Magnuson-Stevens Fishery
Conservation and Management Act, but must also meet mandates of other statutes
including the National Environmental Policy Act.
The Magnuson-Stevens Fishery Conservation and Management Act
In 1976, the United States Congress passed the first fishery legislation, the
Magnuson Fishery Conservation and Management Act (MFCMA or Magnuson Act),
establishing exclusive rights to the management and utilization of the marine fishery
resources from the state's territorial seas to 200 miles, now declared the U.S. Exclusive
Economic Zone or EEZ. The Magnuson Act was later amended and renamed the
Magnuson-Stevens Fishery Conservation and Management Act (MSA or MagnusonStevens Act) (PL 94-265).
The Magnuson-Stevens Act includes national standards for management, outlines
the required contents of fishery management plans, and establishes eight regional fishery
management councils to carry out the management of federal fisheries. The instituted
participatory management regime of the regional councils involves states, fishers, and the
federal government. The fishery management councils are tasked with the responsibility
to monitor and manage the fisheries within their respective regions and are thus required
to prepare fishery management plans (FMPs). The Secretary of Commerce, given
authority for implementing the act, must approve FMPs and regulations promulgated to
implement such plans. The National Oceanic and Atmospheric Administration (NOAA)
carries out the law on the Secretary's behalf, acting through its agency, the National
8
Marine Fisheries Service (NMFS), and in cooperation with the regional councils (Kalo et
al. 1999).
In accordance with the law, the NMFS established advisory guidelines to assist
the councils in the development of fishery management plans, which must abide by the
national standards set out in the federal legislation. Generally, the standards call to
prevent overfishing while achieving optimum yield using the best scientific information
available, and include requirements for 1) stocks to be managed through out their range,
2) the allocation of resources be fair and equitable, 3) efficiency in the utilization of the
resources be considered, and 4) management costs be minimized.
The Magnuson Stevens Act was substantially changed when amended in 1996 by
the Sustainable Fisheries Act (SFA) (PL 104-297). The SFA revised the seven existing
national standards and added three new standards. Key provisions of the SFA for the
existing standards include strengthening the requirements to prevent and end overfishing
and rebuild depleted stocks if found to be overfished. The new standards require councils
to take the importance of fishery resources to fishing communities into account, minimize
bycatch and bycatch mortality, and promote safety of human life at sea. The National
Standards are listed in their entirety in Appendix A.
While all of the national standards affect the management of marine fisheries,
National Standard 1 or the Optimum Yield (OY) standard, is one of the most rigid. This
standard sets criteria to determine stock status and harvest guidelines, and details
subsequent actions if stocks are experiencing overfishing or are determined to be
overfished. In addition, management is required to adopt a precautionary approach when
incorporating national standard 1, and in particular when specifying OY (50 CFR
§600.310).
A "precautionary approach", as used by the NMFS, is an extension of the
precautionary principle that emerged in European environmental politics in the late
1970's (Foster et al. 2000) and has since become enshrined in international as well as
U.S. environmental policies. Much debate has ensued regarding the operational
definition of the precautionary principle, but generally, it requires that those wishing to
develop or utilize a resource must demonstrate that the proposed activity will not cause
harm to the environment or the resource. In addition, if lack of information prevents the
9
demonstration of "no harm", then a conservative regulatory approach should be taken
until supporting evidence is available (Cicin-Sain and Knecht 1998).
Biological reference points are thought to be one part of the overall framework of
the precautionary approach as applied to management of U.S. fisheries (Restrepo et al.
1998). As such, each fishery management plan is required to specify status determination
criteria based on biological reference points, and to the extent possible, include a
maximum fishing mortality threshold and a minimum stock size threshold, or reasonable
proxy thereof. The councils must also include an estimate of maximum sustainable yield
(MSY), where MSY is defined as "the largest long-term average catch or yield that can
be taken from a stock or stock complex under prevailing ecological and environmental
conditions" (50 CFR §600.310). The MSY is used as the basis for setting the Optimum
Yield (OY).
The MSY is to be set using the best scientific information available and must
incorporate appropriate consideration of risk, as required by the second national standard.
When insufficient data are available to estimate MSY directly, Councils are directed to
adopt other measures of productive capacity that can serve as a proxy for MSY (50 CFR
§600.310). In the case of a mixed-stock fishery, MSY should be specified for each
individual stock, and where it cannot, then it may be specified on the basis of one or more
species as an indicator for the mixed stock as a whole, or for the fishery as a whole (50
CFR §600.310). According to the technical guidelines for implementing National
Standard 1, the fishing mortality should not exceed the maximum fishing mortality
threshold for any individual stock in a mixed-stock complex and "the relevant target
control rule should be implemented, regardless of the level of information from which the
rule was developed" (Restrepo et al. 1998).
Action must be taken to end overfishing and rebuild the stock or stock complex to
the MSY level if it is experiencing overfishing and/or is determined to be approaching or
at an overfished level. Overfishing and overfished are defined as "a rate or level,
[respectively], of fishing mortality that jeopardizes the capacity of a fishery to produce
the maximum sustainable yield (MSY) on a continuing basis " (Pub L. 94-265). An
overfished status can only be determined on a stock-by-stock basis and not for an
assemblage.
10
The challenges of managing mixed-stock fisheries are reflected in the MSA and
the subsequent rules published by NMFS, where one exception to the strict requirements
of preventing and ending overfishing, known as the mixed-stock exception, is granted
specifically for multi-species fisheries. In the MSA, Congress calls for the prevention
and consequent end of overfishing in the fishery, where fishery is defined as "one or
more stocks of fish which can be treated as a unit for purpose of conservation and
management" (Pub L. 94-265). Because several stocks are harvested together and are
managed as unit, NMFS has interpreted a mixed-stock as a whole to be a fishery. The
mixed-stock exception allows overfishing of a stock in a mixed-stock fishery, in order to
harvest another stock at its optimum level, as long as the three following criteria are met:
1) demonstrated net benefits to the Nation are long-term, rather than short-term; 2)
technical or operational alternatives to overfishing are considered; and 3) the stock or
stock complex is not driven to a level requiring protection by the Endangered Species Act
(ESA). If the mixed stock exception is invoked, managers are required to know the
biological status of each stock within the mixed-stock fishery and must justify
continuation of overfishing of a stock on the grounds of maximizing benefits (50 CFR
§600.310). To date, regional councils have not invoked the mixed-stock exception for
any U.S. fish stock (Copps, pers. comm.).
Status Determination
The status determination for federally managed stocks is based on the criteria
specified in the MSA, but the NMFS and individual councils determine the fishing
mortality rates and biomass levels necessary to produce MSY for each fishery. For those
stocks contained in FMPs for which overfishing and overfished definitions were
approved, status determinations are based on stock assessment projections (NMFS 2003).
A stock status of "unknown" is applied when an approved definition of overfishing and
overfished exists, but no determination has been made.
Stock assessments provide the means to use various statistical and mathematical
approaches, such as surplus production models, delay-difference models, and age or sizestructured models to predict changes in fish populations and thus provide essential
understanding of the population dynamics of fished species (Jennings et al. 2001, Hilborn
11
and Walters 1992, NRC 1998). The models provide numerical estimates of current and
target fishing mortality rates and current, historical, and target biomass levels by
integrating input data such as catch biomass, age and length composition from species
commercially landed, fishing effort from multiple fisheries, research survey abundance
indices, and length composition from survey catch. However, much uncertainty
accompanies the statistical stock projections. The uncertainty is a result of extrapolating
data, which are sometimes quite limited, to estimate historical, current, and future fish
populations using statistical models.
Fisheries scientists, particularly stock assessment authors, have responded to the
mandate to account for and incorporate uncertainty (CFR 50 §600.335), through greater
use of risk analysis techniques such as Bayesian or "decision-theoretic" and frequentists
methods (Restrepo et al. 1998, Haddon 2001). However, these increasingly complex
methods of determining the status of the stocks and subsequent harvest strategies are
typically applied on a single-species basis, with emphasis placed on the economically
valuable species.
Additional Statute Requirements
While fishery management in the U.S. is guided primarily by the MagnusonStevens Fishery Conservation and Management Act, management actions must also be
consistent with other federal statutes such as the National Environmental Policy Act of
1969 (NEPA). In general, NEPA is an across-the-board national policy of preserving and
protecting the environment and was established with the express purposes to:
"declare a national policy which will encourage productive and enjoyable
harmony between man and his environment; to promote efforts which will
prevent or eliminate damage to the environment and biosphere and stimulate the
health and welfare of man; to enrich the understanding of the ecological systems
and natural resources important to the Nation; and to establish a Council on
Environmental Quality." (Pub. L. 97-258).
Specifically, NEPA requires that a federal agency considers the environmental
consequence of its proposed actions by providing a statement of environmental impacts,
including environmental effects which cannot be avoided, alternatives to the proposed
action, details of the relationship between local short-term uses and long-term
12
productivity, and any irreversible and irretrievable commitments of resources (Pub. L.
97-258). While NEPA does not require actions to minimize nor mitigate the
environmental impacts, it does prohibit uninformed and undisclosed agency action.
Summary
This section describes the requirements of the Magnuson-Stevens Fishery
Conservation and Management Act and the National Environmental Policy Act as related
to U.S. fishery management. In summary, the United States is guided by the mandates
set forth by the MSA, but the regional councils and the National Marine Fisheries Service
are given flexibility to decide how best to meet the prescribed objectives and standards
for the fisheries in which they manage. Management for the species comprising the
majority of the catch is based on stock assessments projecting MSY and the subsequent
determination of OY's by the fishery management councils. This type of management
can be characterized as resource intensive, requiring rich data, and many hours of
manpower. Complex analyses with the goals of projecting absolute abundance and
quantifying uncertainty and risk are sensible for the few valuable species typically
comprising the largest portion of fishery landings that may have abundant information
and data. However, they might not be practical or possible for all of the non-targeted
species caught incidentally, given the costs associated with these analyses, the large
number of non-target species, their relatively low economic value, and the dearth of
available data. Therefore, an analysis that is able to highlight minor species of particular
concern and thus trigger additional analysis and possible management actions may prove
useful.
13
A Regional Scope: The West Coast Groundfish
The Pacific Fishery Management Council (PFMC), hereafter referred to as the
Council, was created to manage the fisheries occurring from three to 200 miles off the
Washington, Oregon, and California coasts and waterways extending into Idaho in the
case of Pacific salmonids. The Council manages the West coast groundfish fishery, the
West coast salmon fishery, highly migratory species, and coastal pelagics. The
groundfish fishery is the focus of this report.
The West coast groundfish fishery can be described as a multi-sector, multi-gear,
and multi-species fishery that occurs off the coasts of Washington, Oregon and
California. The fishery has four components or sectors, including open access, limited
entry, recreational, and tribal. While the trawl fishery harvests most groundfish, trolling
gear, longlines, hook and lines, pots, gillnets, and other gear contribute to total landings.
The groundfish covered by the Council's fishery management plan (FMP) include 82
species that, with a few exceptions, live on or near the bottom of the ocean and include
plueronectids (flatfish), scorpaenids (rockfish), elasmobranchs (skates, rays, and sharks),
and roundfish such as lingcod, cabezon, kelp greenling, Pacific cod, Pacific whiting
(hake), and sablefish.
Rockfish of the family Scorpaenidae comprise the majority of managed species
under the West Coast Groundfish Fishery Management Plan, accounting for 55 of the 82
species. Most of the species of West coast rockfish are members of the genus Sebastes,
with the exception of two species, shortspine and longspine thornyheads, of the genus
Sebastolobus. Sebastes species, the subject of this study, vary greatly in their
morphological and behavioral traits with some species having dull body coloration,
streamlined bodies, and are found schooling in mid-water while others are brilliantly
colored, have thick and deep bodies, and lead a solitary, sedentary, bottom dwelling life
(Love et al. 2002). However, many general life history characteristics are common to
Sebastes species such as extreme longevity, slow growth rate, infrequent recruitment
success and low natural mortality (Parker et al. 2000). These common life history
characteristics may reduce the ability of rockfish species to withstand heavy exploitation
(Parker et al. 2000).
14
Effort targeted towards groundfish species off the West coast of the United States
increased exponentially in the early 1960's when large foreign vessels began harvesting
Pacific ocean perch (Sebastes alutus). The rockfish fishery expanded and soon became
among the most economically valuable commercial and recreational fisheries along the
West coast, accounting for 28% of the revenue generated from commercial groundfish
landings in 1997 (Rogers and Builder 1999). While a handful of rockfish species tended
to dominate the catch, many species of rockfish taken incidentally and often referred to as
"other rockfish" accounted for at least 11% of total generated revenue in 1997 (Rogers
and Builder 1999).
West Coast Groundfish Stock Status
Currently, 26 of the 82 groundfish species have been assessed, fully or at least in
part, using traditional assessment methodology. The level of available data for the
assessed species varies between relatively abundant to minimal, and as a result
subsequent models and analyses range from complex and data-intensive to simple. Given
the paucity and/or poor quality of the data, even if a species is quantitatively assessed, the
overfished status may be considered "unknown" because of the level of uncertainty
associated with the assessment (Figure 4). However, commercially valuable species are
relatively data-rich which allows for determination of an overfished status.
16
Table 1. Overfished West Coast Groundfish. Major stocks are commercially important to
commercial or recreational fisheries while minor stocks have historically been of less
importance.
Common Name
bocaccio
canary rockfish
darkblotched rockfish
Pacific ocean perch
widow rockfish
lingcod
Pacific whiting
cowcod
yelloweye rockfish
Scientific Name
Sebates paucispinis
Sebastes pinniger
Sebates crameri
Sebastes alutus
Sebastes entomeles
Ophiodon elongates
Merluccius productus
Sebastes levis
Sebastes ruberrimus
Landings Category
Major
Major
Major
Major
Major
Major
Major
Minor
Minor
The Council, as directed by the MSA, has defined both overfishing and overfished
to include a fishing mortality rate and a biomass component, respectively. Overfishing is
defined as "a rate of fishing when the catch exceeds the fishing mortality rate needed to
produce maximum sustainable yield (F msy) on a continual basis" (NMFS 2003). The
default Fmsy proxy used for setting acceptable biological catches is based on the species
life history traits such that the F msy proxy is F50% for rockfish, defined as the level of
fishing mortality that results in a spawning potential ratio of 50% of the maximum
(NMFS 2003). The Fmsy proxies are F40% for flatfish and whiting and
F45% for
sablefish
and lingcod. The Council has defined overfished as "a stock biomass less than 25% of
the unfished level or if the current stock biomass is less than 50% of the biomass that
would produce the maximum sustainable yield (MSY)" (NMFS 2003).
In response to the declining populations, the Council has taken many actions to
reduce fishing pressure on depleted stocks while maintaining fishing opportunities for
abundant stocks. One such action includes reconstructing management assemblages to
separate the major rockfish stocks from the Sebastes Complex and dividing the remaining
species, typically minor species, into assemblages (PFMC 2002 b). The defined
assemblages were constructed with respect to the area and depth where they are often
caught: northern or southern latitudes, and near-shore, shelf or slope. The composition of
17
the assemblages was based on a number of co-occurrence studies (Rogers and Pikitch
1992, Rogers et al. 1996, and Weinberg 1994) that suggested certain species of rockfish
are often caught together with respect to latitude and depth, and should be managed as
assemblages. Before the creation of rockfish assemblages, commercially important
species that had been assessed such as Pacific ocean perch, widow rockfish, and
shortbelly rockfish, were managed individually with a separate OY, and other rockfish
were grouped together as part of either the Sebastes Complex or the Remaining Rockfish
assemblages. Optimum yields are set for individual species that are commercially
important and by assemblages for minor species, which are often the sum of either the
allowable biological catch (ABC) or recent catch for all species in the designated
assemblage (PFMC b 2002). For species without an ABC estimate, the averaged recent
catch is used.
Additional measures implemented to protect overfished rockfish include gear
restrictions, reducing annual quotas by up to 50% and creating seasonal and area
restrictions. In 2002, a depth-based area closure was implemented, creating a rockfish
conservation area (RCA) that restricts trawling in depths between 100-250 fathoms (183457 m) from the border with Canada to Cape Mendocino, California, (40°10'N). The
RCA was created with a primary aim to reduce fishing mortality on overfished rockfish
species while allowing continued fishing for healthy stocks. Commercial trawling has
been allowed to continue on either side of the RCA under the presumption that that the
overfished and declining fish are concentrated in the central area of the continental shelf.
The rockfish conservation area will undoubtedly provide some protection to the
overfished stocks, but populations of rockfish that occur outside of the closed area
boundaries may also be declining. In addition, these species may come under increased
fishing pressure if fishing effort is redirected from the closed shelf areas to the near-shore
or slope areas.
While most of the overfished stocks are major components of groundfish
landings, the Council has not invoked the mixed-stock fishery exception even when
minor species, such as yelloweye rockfish or cowcod, have been determined overfished.
This is in part, due to a lively debate on the legality of the mixed-stock exception rule and
potential for ensuing law suits if implemented. Instead, management actions, including
18
those previously discussed, have been taken to reduce overfishing of the major and minor
stocks and have increasingly constrained fishing along the West coast.
Slope Rockfish Assemblage
The slope rockfish management assemblage, the focus of this report, includes
eleven rockfish species listed in Table 2, some of which are primarily found in the
northern management area (U.S.-Canada Border - 40°10' N) or the southern management
area (40°10' N – US-Mexico Border). All slope rockfish, including major and minor
species, were included in this analysis. Of the species classified as slope rockfish, four
major species, Sebastes alutus (Pacific ocean perch), S. crameri (Darkblotched rockfish),
S. melanostomus (blackgill rockfish), and S. rufus (bank rockfish) have been individually
assessed in the past 5 years. Three species, S. diploproa (splitnose rockfish), S. zacentrus
(sharpchin rockfish), and S. reedi (yellowmouth rockfish) were assessed as part of the
Sebastes Complex (Rogers et al 1996). S. diploproa, considered a major species by the
NFMS and the Council, was also individually assessed in 1994. The remaining species,
S. aurora (aurora rockfish), S. aleutianus (rougheye rockfish), S. zacentrus (sharpchin
rockfish), and S. babcocki (redbanded rockfish) have never been assessed.
Table 2. Slope Rockfish Management Assemblages. Major species are denoted by
asterisks (*). Pacific ocean perch and splitnose rockfish are managed individually in the
northern and southern assemblages, respectively.
Northern Slope Rockfish
(North of 40° 10' N. lat.)
aurora
S. aurora
bank
S. rufus
blackgill
S. melanostomus
darkblotched *
S. crameri
redbanded
S. babcocki
rougheye
S. aleutianus
sharpchin
S. zacentrus
shortraker
S. borealis
splitnose
S. diploproa
yellowmouth
S. reedi
Southern Slope Rockfish
(South of 40° 10' N. lat.)
aurora
S. aurora
Bank *
S. rufus
blackgill *
S. melanostomus
darkblotched
S. crameri
Pacific ocean perch S. alutus
redbanded
S. babocki
rougheye
S. aleutianus
sharpchin
S. zacentrus
shortraker
S. borealis
yellowmouth
S. reedi
19
Summary
Management of the mixed-stock West coast groundfish fishery is carried out by
the Pacific Fishery Management Council and the National Marine Fisheries Service
under the guidelines mandated by the Magnuson-Stevens Fishery Conservation and
Management Act and in accordance with the requirements of the National Environmental
Policy Act. The principal fishery-related law does not require in-depth evaluations to
determine maximum sustainable yield for all minor stocks comprising a mixed-stock
assemblage given the limited available data for many stocks. Instead, councils are
required to adopt other measures of productive capacity that can serve as a proxy for
maximum sustainable yield, or alternatively, use indicator stocks to infer status of other
stocks. However, the law does require that overfishing of all stocks be prevented. The
exception to this requirement is the mixed-stock rule, which to date has never been used.
Given that nearly all West coast rockfish populations, both of major and minor
importance, which have been quantitatively assessed have experienced various declines
in abundance, the population sizes of the less abundant, co-occurring species may also be
declining, some potentially to an overfished level. Therefore, a need exists to inventory
the available data for minor rockfish species and conduct a preliminary analysis using an
indicator-based system to identify species that may be of higher concern of being
overfished. As such, management and research efforts can be directed towards those
minor rockfish species that appear to have suffered the greatest decline.
20
METHODS
The Indicator Analysis
Five indicators, two relating to pressure on the fishery resource and three relating
to the stock state, were used in this analysis (Table 3). Pressure indices, which may
provide insight on relative fishing mortality on minor stocks, include commercial
landings and the co-occurrence' of minor species with commercially important species.
State indices, which may provide insight on relative stock status, include the change or
trends of catch per unit effort (CPUE), the proportion of positive tows, and size
composition using research survey data. Management implications of the pressure and
state outcomes are addressed in the discussion.
Pressure Indices
Annual commercial landings along the West coast were summarized for all gear
types. Landings do not include at-sea discards and therefore cannot be considered total
catch of minor species. However, it is assumed that landings data can provide some
information on catch of minor species and hence relative fishing pressure on the species,
even though discards are excluded.
Composition of the survey catch was explored to determine if the minor rockfish
species co-occur with commercially important species such as S. alutus (Pacific ocean
perch), S. crameri (darkblotched rockfish), S. melanostomus (blackgill rockfish), and S.
rufus (bank rockfish), in survey data. If minor species are consistently caught with
commercially important species during trawl surveys, it is assumed that the species cooccur on the fishing grounds and may be caught incidentally with commercial or
recreational gear and therefore fishing mortalities may be similar. The percentage of
hauls where minor species were caught with the commercially important species with a
known status were determined.
'Species co-occurrence is considered to take place when two species are found together
in one haul, irrespective of the catch weight of either species.
U)
w
E (.',
o 0
:r(:)
m cn
=
C)
0
U)
E `I>,
Z
M
0
as
a.
co ._
Li.
2 f_3
ZI—
Q
0
0 cD
ti
co (/)
z
cn _
u_
2
Lo.
ZI—
E >,
E >,
ow
.8
0 CD
-6
m
m
co
co
cn
co _
u... 3
2 El
ZI—
u_3—
2 EF
z f•-•
O
ca
-c
E "e5
O
ces
8 -0
CE
C
O -C
a)
2
ca
0 0
(13 :0 'Fr
_c
t
E
z
CI)
_0a
ca
a) -c
c s
N
a)
E <12
al
- •a a)u- a
-0
oo
a)
>oE
-G 8
TD E •
cC O
CI)
w
0
z
cuw
(I)
0
• C.)
0. 0
U) 0
C
o
•
"E
C
0 Q)
D
a_
0
o
a 0
o a.
0
6CL
6
0
:
0
c a.
a)
-J E
o
0
cc
O
92
0u)
z0
a.
a)
a)
7,5
a)
22
The percentage of co-occurrence was calculated by dividing the number of hauls
where a minor species occurred with a commercially important species, by the total
number of hauls where the commercially important species was caught. The cooccurrence of the individual minor species with each commercially important was
evaluated coast-wide for all three surveys. All years were combined together.
State Indices
The trends of three simple indices, catch per unit effort (CPUE), the proportion of
positive hauls, and size composition were used to detect possible population changes over
time. Each species was treated as a separate stock or unit as required when determining
an overfished status. Although indices vary in precision and clarity of the signals they
measure, the use of multiple indices that give the same signal greatly increases
confidence in results. Individually, each index may not provide much information on the
stock status, however, together the three indices and three data sources may provide
information into the relative health of each population, including changes in the density
of the population, the distribution of the population, and size composition. If many
indices signal negative trends, one may infer that the population is declining.
Conversely, if many indices are indicating positive trends, the population may be
growing and replacing the targeted species which may be declining.
Catch per unit effort (CPUE) has been used as an index of relative abundance and
is considered proportional to the stock size or abundance if catchability is constant over
time and independent of overall stock size (Pennington 1985, Degnbol 2001). CPUE is
typically used to analyze landings data and is often constrained by varying catchability as
a function of changing fishing effort due to imposed regulations and changing
technology. However, research survey data is typically not constrained by changing
regulations and it is assumed in this analysis that any employed change in the research
sampling methodology did not substantially change the catchability of survey gear.
The proportion of positive hauls (or the proportion of the number of hauls where
the species was caught relative to the total number of sampled hauls) was used as an
indicator of change in species distribution. An increasing trend in the proportion of
positive hauls over the time series may suggest an expansion of a species' range while a
23
negative trend may suggest a contraction. A contraction may occur if a species is under
fishing pressure and the population is reduced to smaller and fewer areas. This
contraction may result in greater patchiness and fewer positive hauls.
The arithmetic mean catch per unit effort (CPUE), shown as equation (1), the
associated variance, and the proportion of positive hauls were calculated per strata-year
for each survey for the eleven species comprising the slope rockfish management
assemblage using SAS statistical software.
Catch Weight (kg) * 10,000
Mean CPUE (kg/ha) = Distance Fished (km) * Net Width (m) * 1,000
(Equation 1)
All successful hauls, including hauls where the species were not caught and
consequently had a catch weight of zero, were included in the CPUE analysis.
"Waterhauls" 2 , a problem associated with gear performance during the Alaska Fisheries
Science Center's triennial Shelf Survey, were excluded from this analysis (Zimmerman et
al. 2001). When data were only available for a portion of the strata, as was often the case
in the early years of the AFSC Slope Survey when coast-wide sampling was not
conducted, the mean catch rate in the sampled area was assumed to be constant over the
strata and therefore was expanded to the entire strata.
Size composition, the third state indicator, was perhaps the most problematic for
interpreting population changes from the generated trends. The size composition of a
population has been shown to decline with increasing exploitation as larger fish are
2
A review of the AFSC West Coast triennial bottom trawl survey data suggested several
hauls from early survey years (1977 -1983) which were originally considered to have
successful gear performance and included in biomass computations, by today's standards
were likely to have unsuccessful gear performance. Unsuccessful gear performance was
a result of the footrope loosing contact with the bottom creating a passage through which
fish and invertebrates could escape under the trawl. As such, hauls with unusually small
catches or zero catch of benthic biota were considered "waterhauls" and were thought to
underestimate catch of fish and invertebrates. (Zimmerman et al. 2001).
24
removed from the population (Bianchi et al. 2000, Gislason and Rice 1998, Degnbol
2001) and the extent to which length composition has changed over a time series has
been discerned by calculating mean length (Ralston et al. 1990). However, changes in
mean length can occur as a result of a number of factors including stronger than normal
recruitment (Rogers et al. 1996).
In order to reduce some of the problems associated with mean length, the size of
the largest individuals, specifically those found in the 95th length quantile, was calculated
using data collected during the AFSC shelf and slope surveys. A decline in the 95th
length quantile over time indicates a reduction in the number and size of the largest, and
presumably oldest, individuals from a population. Conversely, an increase in the 95th
length quantile may suggest growth of a population. Specimen data including lengths
and sex of individual rockfish were not collected during the first three years of the
Northwest Fisheries Science Center's Slope Survey and were not included in the size
composition analysis.
Length compositions for males and females were combined per strata-year and
weighted by catch numbers. Lengths were combined under the assumption that length
does not vary by gender. While this assumption may not reflect the true system, it may
be a valid approach because of the limited number of sexed lengths collected for minor
species during the trawl research surveys. The 95th quantile was calculated using SAS
statistical software.
25
Data Sources
Fishery Dependent Data
Fishery dependent data such as commercial landings were used as input data for
pressure indices. Commercial landings data along the West coast were obtained from the
Pacific Fisheries Information Network (PacFin Database) managed by the Pacific States
Marine Fisheries Commission. Recreational landings were not included as data for
pressure indicators because recreational angling does not account for a large portion of
minor slope rockfish landings.
Because non-target species may be discarded at-sea and are not recorded in
landings data, the commercial landings may not accurately reflect total catch of minor
species. In addition, landings data may not accurately reflect population trends of a
species since they are constrained by management decisions and regulations.
Furthermore, a number of problems have been identified with commercial landings
records along the West coast. In particular, rockfish landings were reported according to
market categories such as small red rockfish or large red rockfish during the early years
of landings records, and were rarely identified to species level. In addition, many
differences existed in reporting protocol and sampling procedures between the West coast
states (Sampson and Crone 1997). Therefore, commercial landings data were used to
provide a very general indicator of pressure on the stocks and were not included as data
sources for the state indices.
Fishery Independent Data
Data for the pressure indicator of co-occurrence and for all state indices were
taken from three National Marine Fisheries Service fishery-independent research trawl
surveys that sample the West coast groundfish resources. The surveys include both the
Pacific West Coast Shelf Survey conducted triennially from 1977-2001 and the Pacific
West Coast Upper Continental Slope Trawl Survey conducted annually from 1988-2001
by the Alaska Fisheries Science Center and the Pacific West Coast Upper Continental
Slope Trawl Survey conducted annually since 1998 by the Northwest Fisheries Science
Center. The years comprising the time-series and sampled depth ranges and latitude vary
26
within and between the surveys. The details of the spatial and temporal sampling of each
survey are provided in Appendix B.
One common problem of survey data is that sample sizes are generally small and
therefore generated abundance indices may be noisy (Pennington
1985,
Cook 1997). The
noise in the survey data reflects the within-sampling variability, measurement error, and
longer-term factors, most likely environmental, affecting the species' catchability
(Pennington 1985). This problem is exacerbated for species that are relatively sparse or
uncommon, as may be the case with minor species. In addition, noise may be more
apparent for survey data, such as the AFSC Slope Trawl Survey, where sampled areas
varied during the first eight years of the survey. While noise may affect the ability of a
simple analysis to detect significant trends in survey data, survey data was considered the
best available time series for the state indicator analysis.
Survey data were standardized to include successful hauls sampled in latitude and
depths during each survey-year to reduce the within-sampling variability. Stratifying the
data by depth and latitude also reduced survey noise and was done under the presumption
that species distribution and length composition are affected by both changes in latitude
and depth. For example, Boehlert (1980) found age compositions of splitnose rockfish to
be different between northern and southern areas.
Four strata, including northern-shallow, northern-deep, southern-shallow, and
southern-deep were defined for the shelf and slope surveys (Table 3). The strata were
held static for the assemblage rather than defined for each individual species in order to
examine all species within the management assemblage at one time. Northern and
southern strata were designated using the five International Pacific Fishery Commission
(INPFC) statistical areas (Figure 5). The northern strata were comprised of the U.S.
Vancouver and Columbia areas and the southern strata were comprised of the Eureka and
Monterey areas, and the Conception area when data were available.
27
Depth strata were defined for both the Shelf and Slope surveys and were
determined as half of the depth range consistently sampled by each survey. Depth strata
for the AFSC Shelf Survey included shallow strata (<183 m) and deep strata (183-366
m). Depth strata for the AFSC Slope and NWFSC Slope Surveys included shallow strata
(183-549 m) and deep strata (550-1280 m) (Table 4). This depth stratification was
consistent with stratified methodology utilized by the surveys.
Table 4. Survey Strata. Defined survey strata and their respective latitudes and depth.
Survey
Strata
Latitudes
Depths
AFSC Shelf
Northern-Shallow
43.0 - US Border
55 - 183 m
AFSC Shelf
Northern-Deep
43.0 - US Border
183 - 366 m
AFSC Shelf
Southern-Shallow
36.0 - 43.0
55 - 183 m
AFSC Shelf
Southern-Deep
36.0 - 43.0
183 - 366 m
AFSC & NWFSC Slope
Northern-Shallow
43.0 - US Border
183 - 549 m
AFSC & NWFSC Slope
Northern-Deep
43.0 - US Border
550 - 1280 m
AFSC & NWFSC Slope
Southern-Shallow
34.4 - 43.0
183- 549 m
AFSC & NWFSC Slope
Southern-Deep
34.4 - 43.0
550 -1280 m
29
Statistical Methods
The state indices were calculated in all strata where the species were found, not
only for the areas of greatest abundance as is typically employed for stock assessments.
Using Microsoft Excel, linear regressions of the mean CPUE, Proportion Positive, and
95th length quantile, were performed for each strata-year using the original data scales on
year. As identified by Kimura (1988), a problem exists when linear models are applied on
the original data scales to describe the same change in abundance in a variety of indices
or data sources, such that a single coefficient does not describe the same change of
abundance in all indices. I chose to apply the linear regression model to each
independent strata-year index because I am only interested in whether the trends are
negative or positive rather than quantifying the slopes as an indication of abundance.
Linear trends were considered to occur when the probability was greater than 80% that
the projected slope was significantly different then zero. The trends were considered
highly significant if the probability was greater than 95% that the slope was significantly
different from zero. The percentage of indices for all available strata revealing
significant trends, either positive or negative, and non-significant trends was summarized
for each species. The trends were summarized for all indices.
30
RESULTS
Pressure-State Indicators
General Trends: Pressure Indicators
Commercial landings of the slope rockfish are presented in Figure 6 and Figure 7.
The landings were combined for all gear types and ports along the West coast and do not
include at-sea discards. Landings of major species generally ranged between 250 and
1800 metric tons (mt), with the exception of 1987 when 2354 mt of darkblotched rockfish
were landed (Figure 6). A general declining trend in commercial landings of the major
species occurred over the time-series. The decline is due as much to regulatory changes
as it is to actual stock biomass.
Commercial landings of minor rockfish were typically less than 400 mt, with the
exception of yellowmouth rockfish where landings commonly exceed 700 mt during the
1980's (Figure 7). The general declining trend in commercial landings of
major species was not observed for the minor species, except in the case of yellowmouth
rockfish where landings declined dramatically after 1993 (Figure 7). Since severe
restrictions in commercial landing quotas were implemented in 2000, landings of major
and minor slope rockfish species have been less than 250 mt and 100 mt, respectively.
Detailed figures of species landings by INPFC statistical areas are presented in Appendix
C.
Co-occurrence of major and minor species, averaged over the three data sources,
is presented in Figure 8 and Figure 9. Generally, redbanded, splitnose, sharpchin and
rougheye rockfish commonly co-occurred with Pacific ocean perch and darkblotched
rockfish as well as with each other and other minor rockfish species (Figure 8).
Similarly, Pacific ocean perch and darkblotched rockfish commonly co-occurred with
each other as well as the minor rockfish species. Bank and blackgill rockfish most
commonly occurred together, but occasionally co-occurred with minor species. Aurora
rockfish co-occurred with major species including Pacific ocean perch, darkblotched,
splitnose, and blackgill rockfish in 18-28% of the hauls. Detailed results of the cooccurrence of species within each data source can be found in Appendix D.
35
General Trends: State Indicators
Trends detected in "state" indices, including mean CPUE, proportion of positive
hauls, and length compositions were summarized for all strata with available data (Table
5). The number of strata-indices with data (N) varied for each stock due to differences in
species range and distribution along the West coast. The percentage of total strata-indices
revealing significant trends, both positive and negative, and without significant trends is
reported
Data were available in 20 or more strata-indices for seven of the slope rockfish
species (Table 5). However, two major species, blackgill and bank rockfish, and two
minor species, shortraker and yellowmouth rockfish each had less than 20 available
strata-indices. This is due to a smaller area of distribution along the coast. Significant
trends were found in some of the strata-indices for all species. However, significant
trends were not found in over 50% of the strata-indices for most of the slope rockfish,
with the exception of Pacific ocean perch and redbanded rockfish where trends were
detected in 60% and 57% of strata-indices, respectively (Table 5). Detailed tables for the
results of state indices by strata for each species, including sample size, generated trends
and associated model coefficients can be found in Appendix E.
eeee
000
eeeeeee
oo oo O r-
ee
06 4kr) ceNl er-
N cl"? co 0
71. 6 °
eeee
r- oo
O
eeeeeee
M r- 0, O cn oo N
o
cS
AI.°
•0
2 0
=
cn
40
49 0 0."
cn
0 -0
.5 0
ct:9 4: 0
s..,u3
vi
cu .
0 .---,
›,
1-,
cz
0 . ^-,
4-* "0 cn =
cn 7:j -0 ct
0
0 (.1
0 = a.)
140 a.)
= to
= ••-ci -0
= cc:$
.,-, 1-, (1-) 0
v) cn .g ,0
1-1
-04 a) a, ci
O
—
O c-) u
N
•71: 4
4 c;
,--4
c)
6 71' vO cf•;
n0
7r•
I. 'a.) $. as
-c,'''
5 L-) czl
>
0 = 00
; -4
U
41 0
•
0 cu 0
0 0 cl)
0 ,,..,
" c.411
cz
0 a.).-,)
,0 4-1 (I.) 0
to • - 0 "
ct "0 • - a)
.0
g .,s! s'
,
(..)
c,) =
" 0a).00a)
0.4
.R 4-4 0
•
Q
= 0 t, =
E. v, 8 .7 -5
ct
c 0
vi .0 .0 -4-,
,4-4
cu 0 "t ,4) 444
.O ct
0
•4-,
0 =
OA
10 1_,
A
c tr) —
=
0
0-4 ‘", au
:‘, - 0 C/.c)
a) 0 0
,.. H
eeeeeee
co)
oo
r-
Oc:3
N 00
tr) r- vz)
-10
5 •
4..
t$ "
F.4 > a.
7:'
0
4.)
$_, .5$ ....,
cu tu
^-7'
,= q,
0 all 4-4
-77Z
4-•
-•0 • =
•-" 3 ct
4 ..= to
z • ..— c1 g
.0
00.
04 0.1 4-9 -'
-0 . a) ct bk, 0
a) &I .F..,
O .6 >
N=
. .7
c t c 14-9 ,- '' -`Cj1)
E rt. 8 . _br) "13
E
'-' — ..
ci) 10
U=
,..,) c.i. = -0
tr; o
t ';,:, cs9 .0'CFs'cq
c),
0 ,..0 $._,
-,E)' E t▪ 6, .12
ct = 4-, II c.)
H 0 0 0 ;-1
5
eeeeee
O rf? o o
c;
oo r-
O to °° O °0 O vD
cr)
cf.;
c•-1 4,--4 4-4 —
tr) N oo cn
N N 4-4
N
N
NN
.-=
cn
=
cn
=
u) =
„C
cn cn
cii
. ,-. .-=
i4..
.
..
=
c
+-n v) 0 a)
`i'
c
04 0 - )
L:1
,- 4
c -c-..) --'"-'
, c)
tYi 8
,.,cl= p4 0 .., 0 0 a4 f:4
°
2°
4)
4)
m
a)
-.4,
O
r=4
0
Z.-.) a.) -8 C4
0
D4 "0 "
"=
4a'
0 ,..= --, P44)
0
›,
°-) CI 0 0N 0
....
o
•t.t)
-n ,..4
Z. 1.) 6, -0 ,--
Z.
= =
c,) 0
ce)
" 0
..=
0
g
o
t
m
.
L,0 0 ,.. =
=
z 0,0 ,
03
Ei.
,..0 m
_t0 t ,....,
,..
,..
u
;4
0
•e. 4 -° C 0. C:) 2
--... cztu 1"" F:10 0 0
.0
.z:t . 044
r=4
f:4 VI C•4 "-a") CID
=
U
=
VI
8 -
•
Ir4
37
Summary of Indicator Results for Slope Rockfish Species
Pacific ocean perch (S. alutus)
Pacific ocean perch (POP) were found in northern and southern strata, most
commonly in depths less than 549 m and were most abundant in northern strata in depths
between 183-549 m. Significant trends were detected in 15 of the 25 strata-indices. All
15 trends were negative, seven of which were highly significant. During the shelf survey,
negative trends were observed for CPUE, proportion positive and the 95th length quantile
in the area of greatest abundance. Negative trends were also detected in the proportion
positive in the stratum of greatest abundance in the slope surveys. Commercial landings
of POP reached a maximum of 1800 metric tons (mt) in the early 1980's and has since
steadily declined (Figure 6). Pacific ocean perch co-occurred with darkblotched rockfish
as well as minor rockfish species including rougheye, redbanded, splitnose, and sharpchin
rockfish in the fisheries survey data (Figure 8 and Figure 9).
Darkblotched Rockfish (S. crameri)
Darkblotched rockfish were found in northern and southern strata in depths less
than 549 m and were most abundant in northern strata with depths between 183-549 m.
Significant trends were found in 10 of the 22 strata-indices. Of the 10 detected trends,
seven were negative and three were positive. The negative trends in CPUE, where three
of the four were highly significant (p-value <0.05), and negative trends in proportion
positive suggest a decline in abundance and a possible contraction of species' range.
Two positive trends were detected in the 95th length quantile, although in the area of
greatest abundance in AFSC slope surveys, a negative trend in length composition was
observed. Commercial landings reached a maximum in the late 1980's with landings
greater than 2300 mt but steadily declined after 1987 reaching a low of 200 mt in 2001
(Figure 6). Darkblotched commonly co-occurred with Pacific ocean perch as well as
redbanded, splitnose, sharpchin, and rougheye rockfish in the fisheries survey data
(Figure 8 and Figure 9).
38
Blackgill Rockfish (S. melanostomus)
Blackgill rockfish were most commonly found in the southern strata at depths
between 183-549 m, but occasionally occurred in northern strata. Significant trends were
found in 6 of the 18 possible strata-indices. Two positive trends and one negative trend
were detected in both CPUE and proportion positive indices. In the areas of greatest
abundance for both slope surveys, positive CPUE trends were observed. Significant
trends in the 95th length quantile were not observed. Annual commercial landings of
blackgill rockfish varied between 500-1000 mt during the 1980's but steadily declined in
the 1990's. Landings in 2001 were less than 200 mt (Figure 6). Blackgill rockfish more
commonly co-occurred with bank rockfish although also co-occurred with southern
minor species (Figure 8 and Figure 9).
Bank Rockfish (S. rufus)
Bank rockfish were found most often in southern strata with depths between 183549 m and rarely in the northern strata. Six significant trends were observed, five
negative and one positive of the 13 strata-indices. Negative trends in CPUE and
Proportion Positive were detected in areas of greatest abundance for both AFSC Shelf
and NWFSC Slope surveys. A negative trend in the 95th length quantile was also
observed in the shelf southern-deep strata. A positive trend was observed in the
proportion of positive hauls in the southern-shallow stratum of the AFSC Slope survey.
Similar to the other rockfish species, commercial landings of bank rockfish increased
during the early 1980's, reached a maximum of nearly 1800 mt and steadily declined
thereafter (Figure 6). Bank rockfish co-occurred with blackgill rockfish and occasionally
with southern minor species (Figure 8 and Figure 9).
Rougheye Rockfish (S. aleutianus)
Rougheye rockfish were most often caught in the northern strata and were
abundant between 183-549 m. Significant trends were detected in four of the 24 strataindices. A negative trend was detected for the CPUE in the area of highest abundance
within the shelf survey (northern-deep strata) and a positive trend was detected in the
proportion of positive tows in the shelf northern-shallow stratum. Both a positive and
39
negative trend were found in the length composition or 95th percentile of lengths.
Commercial landings of rougheye rockfish reached a high of 430 mt in the late 1980's,
but steadily declined to landings of 60 mt in 2001 (Figure 7). Rougheye rockfish were
found to frequently co-occur with Pacific ocean perch and darkblotched rockfish (Figure
8) and occasionally with blackgill and bank rockfish (Figure 9).
Aurora Rockfish (S. aurora)
Aurora rockfish, found in both northern and southern strata, were most abundant
in the southern strata with depths between 183-549 m and were rarely found in depths
less than 183 m. Trends were detected in 7 of the 21 strata-indices. Of the detected
trends, three were negative and four were positive. Data from the areas of highest
abundance in both the AFSC Shelf and Slope surveys had positive trends in the CPUE
indices and negative trends in the 95th length quantile indices. These trends suggest that
the density of aurora may be increasing, but the length composition may be changing
with a decreasing size of the largest, and presumably oldest, individuals. Aurora rockfish
were found to co-occur frequently with major southern species, blackgill and bank
rockfish and occasionally with major northern species, Pacific ocean perch and
darkblotched rockfish (Figures 8 and 9). Commercial landings of aurora rockfish
remained less than 150 mt until 1992 when a high of 190 mt were landed. Landings
declined after 1993 and were 45 mt in 2001 (Figure 7).
Redbanded Rockfish (S. babcocki)
Redbanded rockfish were found in the northern and southern strata most
commonly in depths less than 550 m, and were most abundant in strata with depths of
183-549 m. Significant trends were found in 12 of the 21 strata-indices. Of the 12
trends, 11 were negative and one was positive. Highly significant negative trends (pvalue <0.05) in CPUE were detected for three strata within the shelf survey and a
negative trend in CPUE was detected in the slope survey data, suggesting a strong decline
in relative abundance. Five negative trends, two of which were highly significant, were
detected in the proportion of positive tows for all surveys. A highly significant positive
trend was identified in the proportion of positive tows in the area of highest abundance
40
for the shelf survey. The negative trends for size of the largest individuals in the northern
strata of the shelf survey were also significant, suggesting decline in the length
composition. Redbanded rockfish were found frequently with major northern species
co-occurring in an average of 51% and 48% of Pacific ocean perch and darkblotched
rockfish tows, respectively (Figure 8). Redbanded rockfish also co-occurred with minor
species as well as blackgill and bank rockfish (Figure 9). Commercial landings of this
species were greatest in 1984 with a high of 190 mt, however, landings have since
declined and were less than 20 mt in 2001 (Figure 7).
Shortraker Rockfish (S. borealis)
Shortraker rockfish were primarily found in the northern strata with depths
between 183-549 m, but were encountered relatively infrequently. Trends were detected
in three out of ten strata-indices. Shelf survey data revealed negative trends in CPUE and
proportion of positive tows in the northern-deep stratum, which is the stratum of greatest
abundance. A positive trend was detected in the proportion of positive tows in the AFSC
Slope survey data for the northern shallow stratum. Significant trends were not detected
in the size of the largest individuals. This species occurred in less than 5% of tows with
major species (Figure 8 and Figure 9). Commercial landings of this species reached a
high in 1984 and have since declined to less than 20 mt (Figure 7).
Splitnose Rockfish (S. diploproa)
Splitnose rockfish were found in the northern strata with depths <550 m and in all
southern strata. Splitnose were most abundant in the southern strata with depths between
183-549 m. Significant trends were found in eleven of the 27 strata-indices. Of the 11
trends, four were positive and seven were negative. Few trends were detected in the
areas of greatest abundance, although a highly significant positive trend was detected in
the proportion of positive tows in the southern deep strata of the shelf survey. Four
negative trends, three of which were highly significant (p-value <0.05), were detected in
the 95th length quantile suggesting a change in length composition of the population.
Splitnose were found to co-occur with northern species such as Pacific ocean perch and
darkblotched rockfish and southern species such as bank and blackgill rockfish (Figure 8
41
and Figure 9). Commercial landings of this species varied between 300 and 1000 mt
until 1998 when a recorded 1486 mt were landed (Figure 6). After 1998, landings
quickly declined to 117 mt in 2001.
Yellowmouth Rockfish (S. reedi)
Yellowmouth rockfish were only found in the northern strata with depths less than
549 m. Significant trends were observed in two of the nine strata-indices. A strong
negative trend (p-value 0.06) was observed in CPUE of the shelf survey in the area of
highest abundance, the northern-deep stratum. Trends were not detected in any of the
other CPUE or proportion positive indices. However, a highly significant positive trend
(p-value 0.02) was detected in the 95th length quantile. Yellowmouth were not
consistently caught with either Pacific ocean perch or darkblotched rockfish during the
surveys, occurring in less than 5% of tows where the commercially important species
were caught (Figure 8 and Figure 9). Commercial landings of yellowmouth rockfish
oscillated between 300 and 700 mt until the early 1990's when landings consistently
declined (Figure 7).
Sharpchin Rockfish (S. zacentrus)
Sharpchin rockfish were found in northern and southern strata with depths less
than 549 m but were most abundant in the northern strata with depths between 183-549
m. Significant trends were observed in seven of the 22 strata-indices. A positive trend
was detected in CPUE in the area of greatest abundance in the NWFSC slope survey.
Three negative trends, two of which were highly significant, and one positive trend were
detected in the proportion of positive tows for the AFSC shelf and slope surveys. Two
negative trends, one highly significant (p-value 0.02), were observed for the 95th length
quantile, suggesting possible change in length composition. Sharpchin rockfish co-occur
with northern major species Pacific ocean perch and darkblotched rockfish, an average of
38% and 37%, respectively (Figure 8) and occasionally with southern major species such
as blackgill and bank rockfish (Figure 9). Commercial landings of sharpchin rockfish
increased during the 1980's and early 1990's but then declined during the late 1990's. In
2001, landings were less than 5 mt. (Figure 7).
42
Relative Ranking of Concern
A ranking system of relative concern was created based on generated trends in
state indices using a similar approach to the categorical point-scoring method developed
by Millsap et al. (1990) for Florida fish and wildlife species. Trends within each strataindex were given a score relating to the level of concern for population decline (Table 6).
Highly significant negative trends suggest stronger decline and were consequently, given
the highest point values. Conversely, highly significant positive trends were suggestive
of population growth and were given the lowest point values (Table 6). A score of zero
was applied when a trend was not observed (Table 6). It was assumed that trends in the
strata of greatest abundance suggest changes in the core versus margin of the population
and were consequently, given greater weight when ranking species of concern. Weighted
strata scores were summed for each index and species were ranked from highest (1) to
lowest concern (11) (Table 7). The pressure indices used in this analysis, commercial
landings and co-occurrence in survey data, were not intended to reveal population trends
but instead give some indication on the extent of fishing pressure that the species may
have been or continues to be under. Therefore, the results from the pressure indicators
were used to explain and support the observed states rather than used to rank status or
state.
Table 6. Point values used in scoring trends and strata. Higher point values were assigned
to highly significant negative trends and strata with highest proportion of the population.
Trend
Points
Negative Highly Significant
4
Negative Significant
2
No Trend
0
Positive Significant
-2
Positive Highly Significant
-4
Strata
Points
Highest Abundance
2
Other Strata
1
43
Final ranking of concern was based on the individual ranking for each state index.
The CPUE and the proportion of positive tows were considered to be the most
informative "state" indicators of population change since changes in length compositions
could be a result of a number of factors as suggested by Rogers et al (1996). Therefore,
CPUE and proportion positive ranking were given twice the weight of length composition
for the final ranking. The top three species of concern are Pacific ocean perch,
darkblotched and redbanded rockfish (Table 7).
Table 7. Relative ranking for species of concern. Species were ranked in order of
concern, with 1 being the highest concern and 11 being the lowest concern, for
abundance (CPUE), distribution or range change (proportion positive), and size or length
composition. Final rankings reflect combined index rankings.
Species
CPUE
Rank
Prop. Positive
Rank
Length Comp
Rank
Final
Rank
Pacific ocean perch
Darkblotched
Redbanded
Bank
Shortraker
Sharpchin
Yellowmouth
Aurora
Roughe ye
Splitnose
Blackgill
1
3
2
5
3
9
6
11
7
8
10
1
3
4
5
6
2
6
8
9
11
10
2
4
7
5
8
5
11
1
8
2
1
2
3
4
5
6
7
8
9
9
11
There is no direct way to determine the accuracy of the ranking system, but
rankings of assessed rockfish species of known status provided some insight. If
overfished species consistently appear as species of highest concern, the ranking system
may have utility in predicting relative stock status for unassessed species. Therefore,
four assessed species of higher commercial importance, Pacific ocean perch,
44
darkblotched, bank, and blackgill rockfish, were ranked along with the minor unassessed
species. Pacific ocean perch and darkblotched rockfish were ranked as high concern
given that almost all state indicators detected negative signals, with many of those trends
being highly significant. Quantitative stock assessments have projected that Pacific
ocean perch in the Vancouver-Columbia INPFC areas and darkblotched rockfish along
the West coast of the United States, both updated in 2003, to be at overfished levels with
point estimates for spawning biomasses of 25.3% and 11% of virgin levels, respectively
(Hamel et al. 2003, Rogers 2003). Both species are currently in a rebuilding status.
Bank rockfish was ranked 4 th in order of concern with significant declining trends
observed in all three indices, although not highly significant. A quantitative stock
assessment for the bank rockfish population found within Eureka, Monterey, and
Conception INPFC areas projected mid-year biomass to be between 37-45% and
spawning output or number of eggs to be 26-31% of virgin levels for bank rockfish,
however much uncertainty accompanied the biomass projections (Piner et al. 2000). The
overfished status of bank rockfish as determined upon quantitative assessment, is not
overfished.
Blackgill rockfish was of lowest concern (11) with only 2 indices or 11%,
suggesting declining trends and 22% of indices revealing positive trends. Blackgill
rockfish, found within the Monterey and Conception INPFC statistical areas, was
projected to have a fishable biomass of 40-54% of the virgin stock according to the stock
assessment conducted by Butler et al. (1998), but its overfished status is considered
unknown as a result of the high levels of uncertainty associated with the assessment.
Recommended harvest strategies were based on status quo ABC levels for both bank and
blackgill rockfish (Piner et al. 2000, Butler et al. 1998).
Given that the overfished assessed species are ranked as species of overall highest
concern (1 and 2) while bank (not overfished) and blackgill rockfish were ranked as 4
and 11, we were able to infer stock status for the unassessed species. Only one
unassessed minor species redbanded rockfish, was overall ranked between the overfished
and not overfished stocks. Redbanded rockfish was ranked second and fourth for
declining abundance and range, respectively, and ranked seventh in concern for changes
in size composition.
45
While Pacific ocean perch and darkblotched rockfish were ranked relatively high
in all indices, other species varied in their ranking standings among the indices. In most
cases, species were ranked relatively high or low for both CPUE and proportion positive.
However, sharpchin rockfish was ranked 9 th for declining abundance (CPUE) but ranked
second for contracting range or declining distribution (proportion positive). The ranking
for change in size or length composition did not follow the abundance or proportion
positive as closely. For instance, aurora and splitnose rockfish ranked first and second,
respectively, for changes in length composition while ranking 8 th and 11 th in CPUE and
proportion positive.
46
DISCUSSION
The primary goal of this research project was to develop a qualitative analysis
using a system of indicators to determine relative stock status for minor West coast
rockfish species and to identify species that may be of high concern. The results of the
qualitative pressure-state indicator analysis using four species that have been
quantitatively assessed and have varying levels of available data suggest that it may be
possible to determine relative stock status of species and consequently rank species of
potential concern, even for those that may have limited available data. The analysis
projected one minor species, redbanded rockfish, to be of high concern and possibly
being overfished.
Pressure-State Indicators
It is thought that minor species that are compliments to targeted major species
may also suffer similar fishing mortality, however, life history characteristics and species
interactions may determine the population's response to the fishing activity (Sampson,
2002). Recent studies have identified specific life-history characteristics such as large
ultimate size, slow growth rate, and higher age at maturity, more likely to make a species
vulnerable to fishing disturbances (Greenstreet and Rogers 2000).
This analysis revealed that sharpchin and redbanded rockfish frequently co-occur
with commercially important species such as Pacific ocean perch and darkblotched
rockfish, yet the sharpchin rockfish population has not appeared to decline in both
abundance and distribution to the same degree as redbanded rockfish. This may be a
result of varying life history traits in combination with differing habitat associations, for
example, redbanded are thought to be long-lived with a maximum age of 106 years (Love
et al. 2002) and mostly occur over soft-substrate easily accessible by trawls (Eschmeyer
et al. 1983, Rosenblatt and Chen 1972) although they can also be found in untrawlable
habitat (Matthews and Richards 1991). Conversely, sharpchin rockfish are reported to
have a maximum age of 58 years (Love et al. 2002), are generally found in untrawlable
habitat (Matthews and Richards 1991) although they can also occur over soft bottoms
(Eschmeyer et al. 1983).
47
While fishing undoubtedly causes mortality for many non-target species, it may
also provide ripe conditions for population growth of other non-target species
(Greenstreet and Rogers 2000). Such may be the case for the aurora and splitnose
rockfish where almost 20% and 14.8%, respectively, of the strata-indices revealed
positive trends suggesting possible growth in the population. Aurora rockfish are most
often found in the southern areas over non-rocky substrate (NMFS et al. 1998) with a
reported maximum length of 38-41 cm (Echmeyer et al. 1983, Coad et al. 1995, Hart
1973, Moser et al. 1985, On et al. 1998). The maximum age of aurora rockfish is not
known. Eschmeyer et al. (1983) reported splitnose to be associated with soft bottoms,
however, adults can also be found near isolated rock, cobble or shell debris (Yoklavich
2002). Maximum length is reported to be 40.6 - 46 cm (Boehlert 1980, Eschmeyer et al.
1983, Hart 1973). Interestingly, both species were ranked of highest concern for
declining trends in length composition.
Relatively fewer trends were detected in indices for shortraker, rougheye, and
yellowmouth rockfish. While all three species can be found as far south as California,
they are most commonly found in northern areas along the west coast (Love et al. 2002).
Interestingly, yellowmouth rockfish did not often appear in the trawl survey data but were
landed by commercial gear more often than any other minor slope rockfish species during
the 1980's and early 1990's. Yellowmouth rockfish are often associated with high-relief
structures (Love et al. 2002, Eschmeyer et al. 1983, Kramer and O'Connell 1986, Coad et
al. 1995) and for that reason may have been accessible to commercial trawl gear prior to
the implemented roller-gear restrictions but inaccessible to trawl gear utilized by research
surveys. Relatively little is known about the life history of yellowmouth rockfish, but
they are believed to live up to 99 years (Love et al. 2002).
In summary, although species may occur in similar depths and latitudes, their life
history characteristics, the habitats in which they associate, their resiliency to
environmental shifts and resulting ability to withstand fishing mortality may differ.
Species that may not have been commercially targeted may still be declining as a result
of fishing pressure. Therefore, this analysis demonstrates the importance of assessing
each species within an assemblage, even if not commercially important or frequently
48
landed, and basing research efforts and management strategies upon those assessments
rather than recent or historical catch.
Response Indicators
General Management Implications
It is axiomatic that there are never enough data and information to support
management efforts with full certainty, yet managers are expected to incorporate the best
available science when it is available. Moreover, the National Environmental Policy Act
requires all federal agencies to make informed decisions, considering the environmental
impacts and irreversible and irretrievable consequences of proposed actions. The
technical guidelines for implementing National Standard 1 suggest implementing target
control rules regardless of the level of information, and conceivably uncertainty.
Because this analysis does not project maximum sustainable yield, fishing mortality or an
absolute stock size, the official overfished status of minor species may continue to be
"unknown". However, given that the Sustainable Fisheries Act mandates using the best
available science and allows for the use of proxy indicators when insufficient science is
available for maximum sustainable yield designation, a qualitative analysis such as the
one employed in this study can be used to:
•
Reveal stocks that are of greatest concern of potentially being overfished and
therefore trigger in-depth quantitative stock assessment and or management
action
•
Inform managers of the relative stock status so possible population status,
even if not highly certain, can be considered when deciding harvest strategies
Individual councils have the latitude to decide how best to use the information
obtained from the indicator-based analysis. Given the rudimentary analyses, the lack of
information and significant uncertainty, management actions based on this analysis alone
will most likely be limited if employed within the U.S. fishery management system.
However, if a stock is ranked as having high concern of potentially being overfished, an
in-depth analysis to project overfished stock status is reasonable. If it is determined that
49
an indicator-based analysis such as the one used in this study, is "robust" enough to
capture population trends and/or further in-depth analyses are not feasible for minor
species, councils may use the information generated by this analysis and take a
precautionary approach by reducing fishing mortality for species ranked as high concern.
However, by doing so the fishing industry may forgo fishing opportunities and economic
benefits to the Nation.
While the uncertainty associated with this analysis is not quantified as risk as is
the case with stock assessments, there are benefits of using a simple system of indices to
at least prioritize further evaluation of minor species. Foremost, this type of analysis can
be conducted for numerous species at one time and may be less costly than traditional
stock assessments that are typically conducted on a single-species basis using
methodology that is complex and time and data intensive. Additionally, an indicatorbased analysis for minor species may provide managers with some level of information
regarding population trends, which is plausibly better than no information.
A lingering quandary exists for managers when "best available science" is used
in analyses whether for in-depth stock assessments or simple indicator-based analyses,
but population trends or signals are not detected as a result of the dearth of data. As such,
managers have met the requirements of the law to consider and use the best available
science and are subsequently left to decide "precautionary" harvest strategies. This issue
is the center of many debates with suggestions to improve and augment data collection
efforts, employ new assessment methodology utilizing habitat associations and life
history characteristics, and creating marine protected areas. A detailed discussion of the
fishery management tools possessing precautionary properties that may be considered in
limited-data situations can be found in the report generated for National Marine Fisheries
on implementing National Standard 1 (Restrepo et al. 1998).
Implications for West Coast Rockfish Management
Early harvest regulations along the west coast may not have been restrictive
enough to protect some rockfish species from being overfished. However, more recent
restrictive measures, such as reducing quotas, restricting gear, and creating rockfish
conservation areas, have been implemented to protect overfished rockfish species. Since
50
redbanded rockfish has been identified as a species of high concern, it is recommended
that further analyses be conducted to determine definitive status, if possible. Given that
redbanded rockfish occur in many of the same areas as overfished rockfish, as inferred
from the co-occurrence analysis, the Council may find that additional restrictions on
fishing are not necessary to protect the redbanded rockfish. It also is recommend that this
type of analysis be conducted for near-shore rockfish species given that depth-based area
closures on the shelf may result in redirected fishing effort towards the near-shore and
slope environments and increased pressure on rockfish in the near-shore environments.
The Indicator Model
Model Caveats and Recommendations
This study shows that a qualitative analysis for assessing large number of minor
species and identifying species of greatest concern has potential, yet there are limitations
and caveats. Foremost, this analysis is data dependent similar to quantitative stock
assessments. While stocks do not have to be data-rich in order to determine populations
that may be declining, the indicator model is sensitive to sample size and may be more
likely to pick up existing trends for species with ample rather than limited data. As such,
the indicator analysis may not project a species as a stock of concern even though it is
experiencing decline because it is rarely caught by the survey gear.
It was assumed that a linear model would detect negative trends if a species has
dramatically declined to a level that would warrant concern. However, general fishery
science theory affirms that population growth and decline is best described by a logistic
equation. Moreover, populations will decline as a response to fishing and can in theory
reach a state of equilibrium. This does not necessarily equate to an overfished condition.
However, for the purpose of this study which was to determine whether trends within
existing data were positive or negative and not project future trends, a linear model was
deemed sufficient.
It is recommended that the power of this analysis be explored further through
formal statistical analyses. In an effort to create a more robust indicator-based analysis
additional streams of existing data, including observer data and experiential knowledge
could be incorporated. Groundfish observer data which will be readily available in the
51
future may be used to confirm defined management assemblages and co-occurrence and
to verify at-sea discard rates for all minor species. In addition, qualitative information
such as experiential knowledge of fishers could provide more timely information and
observations as well as increase the value and trust of fishers and industry.
Lastly, it is important to emphasize that information including details of life
history, species behavior, habitat associations, species interactions, and ecological
significance remains unknown for many, if not most minor species. Therefore, this type
of analysis may lead to more informed decisions but future research should be conducted
in order to gain better understanding of the exploited species.
52
CONCLUSIONS
The primary objective of fisheries management in the United States is the
conservation and management of fishery resources based on the best available scientific
information to prevent overfishing and assure optimum yield. Accordingly, fishery
managers must maintain all managed stocks above an overfished level while minimizing
management and research costs. The management of mixed-stock fisheries is an
especially difficult challenge given the state of many targeted fisheries worldwide.
Because the numerous non-target species are infrequently landed and may not have great
economic value, many questions arise of how best to manage the mixed-stock fisheries,
and with what levels of information, data, and certainty are decisions considered
acceptable or rational.
Under the U.S. fishery management laws, managers (i.e. the councils) currently
have leeway to manage mixed-stocks and may manage assemblages based on indicator
species. However, this analysis shows that population responses to disturbances,
anthropogenic or environmental, may vary among species of the same genus that occur in
similar areas and depths. Managers may also allow, under the regulations promulgated
by the National Marine Fisheries Service, overfishing of a stock in a mixed-stock fishery
if rigid criteria are met, although much debate has arisen to its legality and this exception
has never been invoked.
Given the laws passed by Congress, the regulations promulgated by the National
Marine Fisheries Service, and the state of rockfish fisheries along the West coast, it was
sensible to inventory and evaluate the available data for each species within the slope
rockfish management assemblage and subsequently conduct a rudimentary indicatorbased population analyses. The study projected one minor rockfish stock, rebanded
rockfish, to be of high concern of declining populations.
The system of simple "pressure-state" indices used in this study, could provide a
systematic process for detecting other minor species with declining populations that are
of concern and thus be used to prioritize further stock assessment evaluations based on
probable population status instead of commercial landings. Additionally, because the law
allows managers to use other measures of productive capacity as proxies for maximum
sustainable yield when deciding harvest strategies, the relative stock status of minor
53
rockfish species determined from this indicator-analysis could be used if further in-depth
evaluations of minor stocks of concern are not feasible.
This type of analysis holds potential for prioritizing in-depth evaluations of minor
rockfish species in addition to informing the management process. However, it can only
be incorporated into the complex fishery management system in the U.S. if the indicators
themselves are shown to be "robust" enough to indicate actual stock status and are
scientifically defensible, the public understands the analysis, and less certainty is
accepted to accompany decisions regarding minor species.
54
WORKS CITED
50 C.F.R. § 600.310. 1998. Magnuson-Stevens Act Provisions; National Standard
Guidelines; Final Rule. Volume 63, Number 84.
Bianchi, G., H. Gislason, K. Graham, L. Hill, X. Jin, K. Koranteng, S. ManickchandHeileman, I. Paya, K. Sainsbury, F. Sanchez, and K. Zwanenburg. 2000. Impact of
fishing on size composition and diversity of demersal fish communities. ICES Journal of
Marine Science. 57: 558-571.
Boehlert, G.W. and R.F. Kapenman. 1980. Variation of growth with latitude in two
species of rockfish (Sebastes pinniger and S. diploproa) from the northeast Pacific ocean.
Mar. Ecol. Prog. Ser. 3: 1-10.
Butler. J., L.D. Jacobson, J.T. Barnes. 1998. Stock assessment for blackgill rockfish. in:
Status of the Pacific coast groundfish fishery through 1998 and recommended acceptable
biological catches for 1999: Stock assessment and fishery evaluation. Pacific Fishery
Management Council. Portland, Oregon.
Cicin-Sain, B. and R.W. Knecht. 1998. Integrated coastal and ocean management:
concepts and practices. Island Press. Washington, D.C. 517p.
Coad, B.W., H. Waszczuk, and I. Labignan. 1995. Encylopedia of Canadian Fishes.
Waterdown, Ont., Canadian Sportsfishing Productions. 928p.
Cook, R.M. 1997. Stock trends in six North Sea stocks as revealed by an analysis of
research vessel surveys. ICES Journal of Marine Science. 54: 924-933.
Copps, S. 2003. Personal communication.
CSD, United Nations Commission on Sustainable Development. 2001. Indicators of
sustainable development: Guidelines and methodologies. Working Group Report. 48p.
http://www.un.org/esa/sustdev/natlinfo/indicators/isdms2001/isd-ms2001isd.htm
(05/27/03).
Degnbol, P. 2001. The knowledge base for fisheries management in developing
countries: alternative approaches and methods. Report to Nansen Programme Seminar on
alternative methods for fisheries assessments in development, 24-25 January, Bergen,
Norway. Working paper no 5-2001. Institute for Fisheries Management & Coastal
Community Development. http://www.ifm.dk/publicah.html (07/2103).
Degnbol, P. 2002. The ecosystem approach and fisheries management institutions: the
noble art of addressing complexity and uncertainty with all onboard and on a budget.
111-, ET 2002 Conference, August 19-22, Wellington, New Zealand. Conference
Proceedings. Paper no. 171. http://www.ifm.dk/publicah.html (07/21/03).
55
EEA (European Environmental Agency). 2003. An indicator-based approach to
assessing the environmental performance of European marine fisheries and aquaculture.
Technical Report no. 87. 61p. http://reports.eea.eu.int/technical_report_2003_87/en.
(05/27/03).
Eschmeyer, W. N., E.S. Herald, and H. Hammon. 1983. A field guide to Pacific Coast
fishes of North America. Houghton Mifflin, Boston, Massachusetts. 336p.
FAO, Food and Agriculture Organization, Fishery Resources Division. 1999. Indicators
for sustainable development of marine capture fisheries. FAO Technical Guidelines for
Responsible Fisheries. No. 8. Rome. 68p.
http ://www.fao.org/DOCREP/004/X3307E/X330'7E00.HTM (5/27/03).
FAO, Food and Agriculture Organization. 2001. The development of indicators of
sustainable development (ISD) in fisheries. Meeting report.
http ://www.fao.org/DOCREP/MEETING/003/X9430E.HTM (05/27/03).
Foster, K., P. Vecchia, and M. H. Repacholi. 2000. Science and the Precautionary
Principle. Science. Vol. 288 Issue 5468, p979, 2p.
Gislason, H., and J. Rice. 1998. Modeling the response of size and diversity spectra of
fish assemblages to changes in exploitation. ICES Journal of Marine Science. 55: 362370.
Greenstreet, S.P.R., and S.I. Rogers. 2000. Effects of fishing on non-target fish species.
in: Effects of fishing no non-target species and habitats; biological, conservation, and
socio-economic issues. eds. M.J. Kaiser and S.J. de Groot. Blackwell Science.
Hadddon, M. 2001. To be Bayesian or to Bootstrap: what is the risk? Towards
Sustainability of Data-Limited Multi-Sector Fisheries. Australian Society for Fish
Biology Workshop Proceedings, Bunbury, Western Australia 23-24 September 2001.
Newman, S.J., Gaughan, D.J., Jackson, G., Mackie, M.C., Molony, B., St. John, J. and
Kailola, P. (Eds.). Fisheries Occasional Publications No. 6, May 2003, Department of
Fisheries, Perth, Western Australia, 186p. http://www.asfb.org.au/pubs/2001. (05/27/03).
Hamel, 0., I.J. Stewart, and A.E. Punt. 2003. Status and future prospects for the Pacific
ocean perch resource in waters off Washington and Oregon as Assessed in 2003.
Unpublished report.
Hart, J.L. 1973. Pacific Fishes of Canada. Bull. Fish. Res. Bd. Canada. 180: 730p.
Hilborn, R. and. Walters, C.J. 1992. Quantitative fisheries stock assessment: choice,
dynamics, and uncertainty. Chapman and Hall. New York. 570 pp.
Jennings, S., Kaiser, M.J., and Reynolds, J.D. 2001. Marine Fisheries Ecology.
Blackwell Science. Oxford, UK. 417p.
56
Kalo, J., R. Hildreth, A. Rieser, D. Christie, and J. Jacobson. 1999. Coastal and Ocean
Law: Cases and Materials. American Casebook Series. West Group. St. Paul,
Minnesota. 748p.
Kimura, D. 1988. Analyzing relative abundance indices with log-linear models. North
American Journal of Fisheries Management. 8: 175-180.
Kramer, D.E. and V.M. O'Connell. 1986. Guide to Northeast Pacific rockfishes genera
Sebastes and Sebastolobus. University of Alaska Sea Grant. Anchorage, Alaska.
Marine Advisory Bulletin. 25: '78p.
Le Gallic, B. 2002. Fisheries sustainability indicators: The OECD experience. Joint
workshop EEA-EC DG Fisheries-DG Environment on "Tools for measuring (integrated)
fisheries policy aiming at sustainable ecosystem. Oct. 28-29, 2002. Brussels, Belgium.
w ww.oecd.org/pdf/M00040000/M00040632.pdf (05/27/03).
Love, M., M. Yoklavich, and L. Thorsteinson. 2002. The Rockfishes of the Northeast
Pacific. University of California Press. Berkley, California. 405p.
Mathews, K.R., and L.J. Richards. 1991. Rockfish (Scorpaenidae) assemblages of
trawlable and untrawlable habitats off Vancouver Island, British Columbia. N.Am. J.
Fish. Manag. 11:312-318.
Millsap, B.A, J.A. Gore, D.E. Runde, S.I. Cerulean. 1990. Setting priorities for the
conservation of fish and wildlife species in Florida. Wildlife Monographs. 111:1-57.
Moser, H.G., F.M. Sandknon, and D.A. Ambrose. 1985. Larvae and juveniles of aurora
rockfish, Sebates aurora, from off California and Baja California. Can. Tech. Rep. Fish.
Aquat. Sci. 1359:55-64.
NMFS, National Marine Fisheries Service, Alaska Department of Fish and Game, and
North Pacific Fishery Management Council. 1998. Essential Fish Habitat Assessment
Report for the Groundfish Resources of the Bering Sea and Aleutian Islands Regions.
Anchorage, AK.
NMFS, National Marine Fisheries Service. 1999. Ecosystem based fisheries
management. A Report to Congress by the Ecosystems Principles Advisory Panel. U.S.
Dept. Commerce, NOAA, Natl.Mar.Fish. Service.
NMFS, National Marine Fisheries Service. 2003. Annual report to Congress on the
Status of U.S. Fisheries – 2002, U.S. Dept. Commerce, NOAA, Natl. Mar. Fish. Serv.,
Silver Spring, MD, 156p. http://www.nmfs.noaa.gov/sfaireports.html. (05/27/03).
NRC, National Research Council. 1998. Improving Fish Stock Assessments. National
Academy Press, Washington D.C. 177p.
57
Nielsen, J.R. and P. Degnbol. 2001. Indicators as a basis for robust and acceptable
fisheries management. Presented in the Regional Technical Consultation on Indicators
for Sustainable Fisheries Management in ASEAN Region, Haiphong, Vietnam, 2-5 May.
Working paper no. 4-2001. Institute for Fisheries Management & Coastal Community
Development. http://www.ifm.dk/publicah.html (07/22/03).
OECD, The Organization for Economic Cooperation and Development. 1997. Towards
sustainable fisheries. Economic aspects of the management of living marine resources.
OECD, Paris. 268p.
On, J.W., M.A. Brown, and D.C. Baker. 1998. Guide to rockfishes (Scorpaenidae) of
the genera Sebastes, Sebastolobus, and Adelosebastes of the Northeast Pacific Ocean.
NOAA Tech. Memo. NMFS-AFSC-95, 46p.
PFMC Pacific Fishery Management Council. 2002 a. Groundfish Information.
http://www.pcouncil.org. (22, July 2003)
PFMC, Pacific Fishery Management Council. 2002 b. Status of the Pacific Coast
Groundfish Fishery Through 2001 and Acceptable Biological Catches for 2002: Stock
assessment and fishery evaluation. Pacific Fishery Management Council. Portland, OR.
Parker, S.J., S.A. Berkeley, J.T. Golden, D.R. Gunderson, J. Heifetz, M.A. Hixon, R.
Larson, B.M. Leaman, M.S. Love, J.A. Musick, V.M. O'Connell, S. Ralston, H.J. Weeks,
and M.M. Yoklavich. 2000. Management of Pacific rockfish. Fisheries. 25(3):22-30.
Pennington, M. 1985. Estimating the relative abundance of fish from a series of trawl
surveys. Biometrics. 41:197-202.
Piner, K., M. Schirripa, T. Builder, J. Rogers, and R. Methot. 2000. Bank rockfish
(Sebastes rufus) stock assessment for Eureka, Monterey, and Conception INPFC areas
north of Pt. Conception, California. Appendix in: Status of the Pacific coast groundfish
fishery through 2000 and recommended acceptable biological catches for 2001: Stock
assessment and fishery evaluation. Pacific Fishery Management Council. Portland, OR.
Public Law 94-265. October 11, 1996. (16 U.S.C. §1802). Magnuson-Stevens Fishery
Conservation and Management Act as amended by the Sustainable Fisheries Act.
Public Law 97-258, Sept. 13, 1982. (42 U.S.C. § 4321, 4332). The National
Environmental Policy Act of 1969, as amended by Pub. L. 91-190, 42 U.S.C. 4321-4347,
January 1, 1970, as amended by Pub. L. 94-52, July 3, 1975, Pub. L. 94-83, August 9,
1975.
Public Law 104-297, Oct. 11, 1996. (16 U.S.C. § 1801). The Sustainable Fisheries Act
to amend the Magnuson Fishery Conservation and Management Act.
58
Ralston, S., A.D. MacCall, D.E. Pearson. 1990. Reduction in mean length and
exploitation of central and northern California. in: Status of the Pacific coast groundfish
fishery through 1990 and recommended acceptable biological catches for 1991. Stock
assessment and fishery evaluation. Pacific Fishery Management Council, Portland, OR.
Restrepo, V.R., G.G. Thompson, P.M. Mace, W.L. Gabriel, L.L.Low, A.D. MacCall,
R.D. Methot, J.E. Powers, B.L. Taylor, P.R. Wade, and J.F. Witzig. 1998. Technical
guidance on the use of precautionary approaches to implementing National Standard 1 of
the Magnuson-Stevens Fishery Conservation and Management Act. NOAA Technical
Memorandum NMFS-F/SPO
Rogers, J.B. and E.K. Pikitch. 1992. Numerical definition of groundfish assemblages
caught off the coasts of Oregon and Washington using commercial fishing strategies.
Can. J. Fish. Aquat. Sci. 49: 2648-2656.
Rogers, J.B., M. Wilkins, D. Kamikawa, F. Wallace, T. Builder, M. Zimmerman, M.
Kander, and B. Culver. 1996. Status of the Remaining Rockfish in the Sebastes
Complex in 1996 and recommendations for management for 1997 in: Status of the
Pacific coast groundfish fishery through 1996 and recommended acceptable biological
catches for 1997: Stock assessment and fishery evaluation. Pacific Fishery Management
Council. Portland, OR.
Rogers, J.B., and T. Builder. 1999. Pacific coast groundfish fisheries in: Our Living
Oceans. Report on the status of U.S. living marine resources, 1999. U.S. Dep. Commer.,
NOAA Tech. Memo. NMFS-F/SPO-41.
Rogers, J.B. 2003. Darkblotched rockfish (Sebastes crameri) 2003 stock status update.
Unpublished report.
Rosenblatt, R. H. and L. Chen. 1972. The identity of Sebastes babcocki and Sebastes
rubrivinctus. Calif. Dept. Fish and Game 58: 32-36.
Salia, S.B., and Gallucci, V.F. 1996. Overview and Background In: Stock Assessment:
Quantitative methods and applications for small-scale fisheries eds: Galluci, V.F., Salia,
S.B., Gustafson, D.J., and Rothschild, B.J. Lewis Publishers. Boca Raton, Florida.
Sampson, D.B., and P.R. Crone. 1997. Commercial Fisheries Data Collection Procedures
for U.S. Pacific Coast Groundfish. NOAA Tech. Memo. NMRS-NWFSC-31, 189 p.
Sampson, D.B. 2002. Dynamics of Marine Biological Resources Lecture Notes.
http://oregonstate.edu/instruct/fw431/sampson/index.htm. (07/21/03).
Weinberg, K.L. 1994. Rockfish assemblages of the middle shelf and upper slope off
Oregon and Washington. Fishery Bulletin. 92:620-632.
59
Welcomme, R.L. 1999. A review of a model for qualitative evaluation of exploitation
levels in multi-species fisheries. Fisheries Management and Ecology. 6(1): 1-19.
Zimmerman, M., M.E.Wilkins, K.L. Weinberg, R.R. Lauth, and F.R. Shaw. 2001.
Retrospective analysis of suspiciously small catches in the National Marine Fisheries
Service west coast triennial bottom trawl survey. AFSC Processed Report 2001-03.
National Marine Fisheries Service. Seattle, Washington. 135p.
60
APPENDICES
61
APPENDIX A.
National Standards
1. Conservation and management measures shall prevent overfishing while achieving, on
a continuous basis, the optimum yield from each fishery for the United States fishing
industry.
2. Conservation and management measures shall be based upon the best scientific
information available.
3. To the extent practicable, an individual stock of fish shall be managed as a unit
throughout is range, and interrelated stocks of fish shall be managed as a unit or in close
coordination
4. Conservation and management measures shall not discriminate between residents of
different States. If it becomes necessary to allocate or assign fishing privileges among
various United States fishermen, such allocation shall be (A) fair and equitable to all such
fishermen; (B) reasonably calculated to promote conservations; and (C) carried out in
such manner that no particular individual, corporation, or other entity acquires an
excessive share of such privileges.
5. Conservation and management measures shall, where practicable, consider efficiency
in the utilization of fishery resources; except that no such measure shall have economic
allocation as its sole purpose.
6. Conservation and management measures shall take into account and allow for
variations among, and contingencies in, fisheries, fishery resources, and catches.
7. Conservation and management measures shall, where practicable, minimize costs and
avoid unnecessary duplication.
8. Conservation and management measures shall, in consistent with the conservation
requirements of this Act, take into account the importance of fishery resources to fishing
communities in order to (A) provide for the sustained participation of such communities,
and (B) to the extent practicable, minimize adverse economic impacts on such
communities.
9. Conservation and management measures shall, to the extent practicable, (A) minimize
bycatch and (B) to the extent bycatch cannot be avoided, minimize the mortality of such
bycatch.
10. Conservation and management measures shall, to the extent practicable, promote
safety of human life at sea.
62
APPENDIX B.
Comparison of Research Survey Data Sources.
VD VD VD VD AD VD VD VD
VD VD VD VD VD VD VO VD
M rn rn rn on on on rn rn
'ea
111111
s.
0.)
I
ti.)
U.4
0 0
P=1
0
1:3
a
c.)
a.)
11
•4
I
1
gcl
as
Y C.)
U
4.)
0
a.)
1-1
1-4
1-i
o o
Gcl ti1
U
00 Zi3 00
o
o
1-1
o
1-•
o
I
cat
1-4
o
Cm)
u *E4,-5 'u075
cat
n
•
1
1
e
1
1n1
00 00 00
111111
rn on on on on on Cf) rn on on on on
oo oo oo oooo oo oo oo oo oo 00 00
0.0
0-4 re re r. re rr r.
c,4
cat
r
cn
Tr
Ti
Tr
111/11
VD VD nID n.0 nC)
nC)
M rn Mcncncncncnce)
cs)
"C3
1
0 0 0
ry N
on on on
00 00 00
— re r.
1.) a.) a)
Pq
cat cat
U
/
I
un tI1 vn vn un
vn
vn un vn vn
vn un vn
c»
0 0 0 0 0 0
0 0 0 0 0
00 00 00 00 00 00 0
00 00 00 00 00 00
NN
NCA
NN
CA
CV
CA N CA CA
0 .
,0
n ••n• — •n ••n•
N CD Cr
CN N 141 00
wr--00 00) VD
00 00 0\ CN CN
CA 01 ON CT CT 01 C11 crs CD
rm
cv
N
N In VD
CA
cn 0.0
00
N tri
N
Tr
7h "1. •ct Tr
N
ON r- N
Yr) cn Tr
vn
N
N O
e5 cn
Tr Tr 7r
CA
00 01 0
N Cr)
∎C) 5 Cn
00 00 ON c:tn C \
01 01 C51 01 0 0
01 01 01 Cs 01 0\ 0A0\ a\C.% 0 0
"-I -0 0-,
N
a)
N
oo cn CD CN r-- VD
00
N Cl O
CD r")
--,CV-,CD
,,CD
,,
0 81 01 6 cA CA 0 01
cl,,) 0 0 ,- 0 0 ,''''i 0
4m)
CI
cd
1
gz 71-
° 0 8--
4.
0
;.•
rn4
E
4
c _,
c.4_,
•
ti)
a.)
a.)
>,
ti.)
›,
c4..,
4.)
cl)
<1.)
4)
00 00 GO 00 00 00 00 00 00
0
N
6
>> >1
EU EN E
LI E
L) E
z
zU Elj
1D V) V) C/) V) V) V) C/) V)
a
'at O 00 O et O
N re
6
O
O 23 O O
N N N h N N nC)
0000000
a.)
CA 00
CD O
1
IIIIII
N C-- CA C.-. CV 00 8 8
° -z.. R ° -C.:). -7-',
cu
N
O
(1)
v)
V) V) v)
a.) 0 a) 0 4.) 4.)
4.)
f:14 SZ.•
fZ• fZ• fZ-1 fr).•
f:l•
0 0 0 0 0 0 0 0 0
00 00 00 00 00 00 00 00 00 00 00 00
U U C.) C.-) C..) C.) C..) C.-) C..) C.) U U
00 00 00 00 00 00 00 00 00 00 00 00
4-4 4.4 V•o
<4 <4 <4 <4 <4 <4<4 <4 <1G
71'
• NN
CI\ 01 01
0 0 0
cn 00
I
I
cc) N
1
0 N
N
CD CD CD
64
APPENDIX C.
Commercial landings.
Commercial landings by INPFC area for slope rockfish stocks were combined for all gear
types and do not include at-sea discards.
71
APPENDIX D.
Percent Co-Occurrence Tables.
The percentage of co-occurrence was calculated by dividing the number of hauls where
speciesx occurred with speciesy, by the total number of hauls where speciesy was caught.
The co-occurrence of the species was evaluated coast-wide for all three surveys and is
reported in the columns of the following tables.
78
APPENDIX E.
State Indicator Results.
Results from state indicators are presented for individual stocks. Mean CPUE and mean
Proportion Positive were calculated for each year of the time series. Sample size (N) is
the number of years or observations used in the regression analyses for mean CPUE and
Proportion Positive. The number of years in which lengths were collected for each
species reported as (N t ). Bolded strata indicate the area of greatest abundance. Linear
trends were considered to occur when the probability was greater than 80% that the
projected slope was significantly different then zero and are denoted by an asterisks (*)
next to the slope coefficient. Highly significant trends, denoted by double asterisks (**),
existed if the probability was greater than 95% that the slope was significantly different
from zero.
T)
L)
z:
N
`cs
on
15
ett
=
0 g
rD
00 `1?
N
O
Ch
00
o
o
6
C
en WO rN
000
'1'
CN
CN
'Tr
6 e4
•
00
en cS "1
0 CZ
0
c/
°
c©.
O o
0
6 ©
cn
0 0 0
VP ,-1
CD 0 0
© ci c:5
en N
CD
4::
0
cz
c;
CC
s
in
7:4
N
o
4::,
,-0 on
7h 00
on
0 CD CD
0o
• 0.
OO
c? 6 6 W
e ° o
,r)
*
,-1 9 VO
O * O
w o
'71'
O O
c o c:::)
0
•
6
4
O
cA
e5
cc oo
8
0. o
oN
Oo
cn
cn
O
:D5
WO
cq
CD "*
CD
CD Ci c) CD
*4'•
U-
0(7'
o
00
CD 0
el
v.* r,
o
o c`l
4::. o 8
00••
°
g' 9
C'i!
• Oo
©Cd
GP
O
cS
o
o
cl")
csi
c'
o
o
N
oo
co.
CD
QS
±P
r-
a)
CI)
bA
O
O
O
0
0
4.
0
N
E
CN CN CN CN
CN CN 00
rn
o ct,
a) g 0.,
a)
7,1 co
= It C
luc
ci)
0 ca. 0 to.,
a) ,--.
a)
74 u
;5, A ,.z A
C 0. 0
a)
a) 7,,s
= 1.
S
A
'
c C
CA
v?
i =
a)
• g a)
E 7F,
a) =
=
= 6 , =
O o o 0
4 4 c/9 z
88
U_
O
c+-n ciw
co
a)
rip
•
C..)
a)
a.)
..0 ,4 ..0 .0
1-ti t
-;
1 GO
W CL) CU tll
Q. 0., 0., 0.,
o 0 0 0
cn ci.) cr) Ei)
U U
v) ct) v) v)
4-1 ;.T.4 GI* 4.4
L) L) C-) C..)
v) v) v) v)
.e < <
7sI
C4
(19
a)
• ••=
.)E 0
a)
a)
=
a)
..c
a)
-c
=
t
,.=
i5
.=
t0== 0
4:.)
n
4-,
6, — o 0
6© 4
O 4 o cn
o CA
z cn
z c4
r4 Qn GO GO
<
rn
iet
'V a) a)
a)
CU (=LI 014
o 0 0 0
ci) 7)
cn
L) C..) U C..)
v) C4
Z44
N
N
CI)
N
O
141)
N
C
00
CIC?
k
cr)
\
O
00 N
to
cl cr)
O
O
OO
6
O
C;
no
N
O
CS
N
W.4
CA
O
O
O
∎10
O
O
O
O
00
O
O
cn
6
,,,
c)
— c)
C
c:)
co. •
oIn•N
c;
00en
S
as
co 6
∎0n
C;
te) 0
G5 0
N
N
O
ate
O
O
O
C/)
z
a.)
LC;
N
71'
1-
O CIS
4
li
0
M
en en
3 tz. 03
o a) -071 a)
cu
0
•
"rci a)
9
(,) 9
,, E
a.)
0.)
z
O
Oz c/)
z
0
"4 9
v' =
,
a) o6
t0 =
04 -a)
= t 4 '5'
t 0 -... o
,o — 0
o C/)
c4
a)
a) 0)
0. f:14
G. a)
O 0 0 0
cl) cr) V) FA
U U C.) U
v) ci)
v)v)
w.
Z
z
P14
n41,
csi
nC)
In
vj
In
O
▪
1-n1
6
con
z
M
nc:5
(-4
N
er
O
O
O
O
N
ire
kr)
nC)
cr.;
kr)
V:, ON
00
eee 0 kr)
o
o o
o o
6 ci co
`4
a
O
M ON t-o
6 o 6 6
N '1: V')
*
•
* *
N CC
0 0 C)
0 0 0 O.
C0.) C? 0
o
P.T.4
.
8
o
CI
*
en
In
O0
0
C?
OS5
1-1
el
•71-
•71-
crn
.c)
ts:
•-n4
71c)
•
csn
'Ca
xnI
6 6
0 er o 0
71• 4? c; o
9 , i
a)
1-1
n0
0 N
6 6
* *
* N *
,...., In c::)
z
*
*
*
Ci;
0 (.4 0
o
6
a
T
zi
Z
N
00
*"
41
ON ON 0∎ O'N
O Cr
a.)
0
0.)
(94
—01 0
,..0
ACA
Ea)E
E
a) 5 a) .E
,.c 6 = =
0
S' o
• Z C/S) Cip
4. t•• <4.
v..
•
CIS
ON
00
o a.,
a)
Tai a)
0 (:).
n7
4
cc
:
^,,3
a)
a)
E
,D w? E
<4 ci.)
En
(I) a.)
C14 C14 rZ4 C14
715 CD 1.) Ci.)
-a = -C =
0 0 0 0
v) cl) v) cl)
(..) c...) C.) C—.)
CA vl 0) v)
c4 cA c4 ri)
1.4 Gro -1 40
< -e < <
en
ez
3
ta4 0
19 73 cl)
11
0)A ..=
6
e
0
y=
0 -E
..=ot = =
0
0
6 4 o cn
Z
en
C.) C..) C—) C...)
z c4 cA v)
40 44 40 4.,
-et < < <
n =
cC7
=6 {,E.) ' 1
4) .=
0
E
a)
4) -
= to ,.z
_,,
,5 =
o
ct 4 o r4
V)
Z
1) C) a) 0
0.1 s:a P.
0
0
0
0
CA Cn CA ci)
C.) C.) C.) C..)
cn v) v) r..)
5
4
tr)
1-0
O
00
GC
00
O
*
4,
N
o
4:::
o
c::
cn
o
o
11
O
*
O
*
eq
C:
4i1
z
L.1
O.
c::
el
1.o
ci
8
.v.
(:::).
0
C::
C?
1.*
0
on
CT
en
o co
ct. g al
ci)
71 4)
74 n
4)
,.c A ,.=
C4 a
E s. u?
w E a)
L.•
604
c?
o
eu 4 0 =
N
© 04c:D 01.i
fl.)
a.)
Ts 4.) -,-, cu
.= n = n
1
L
. E
0 E ti
sJ =
a.) =
0
Li
0 0 0 0
z Z r./9 VI
.0 0
-4=3
00
I.•
co Z o C/)
CA
Z
4, c+4 c.-, c4–,
a) 4.) 0 0
0.
a
o oa oa o
VI ciI r,1 E7)
0 a) 0 0
..0 4 = =
clI VI CID (II
C
.) C..) C..) C..)
z co) C/D CI)
40 ;10
.1.4
< -et < <
C.) C...) L) C.)
V) c/I c.II c/I
T.1
r-LI 40
0 C1
o
0
Ts cu ^c't 0
4 = 0
'T
0 ,L,
E 0.)
at = to =
cC Q
E c) E
"-Fe 'g "E
0
6
o Z 0 V)
C4
Z
40000
= a ca.
c 71
o o o
cA
V) VI
C.) C.) C.) C..)
vi z z z
;T••
AtC < < <
ZZZZ
tr)
N
1n1
7:4
M
tfl tin
00
O
rl
00
C7;
NC ON
N N N
O
Oo
oo
o
6 6 6 cz
O
O
eri
ri
00
d-
o
o O
O
_O
1n••1
e4M
O
O
71-
er)
OM o
o 6 6 cz
tr)
O
0
C O6
n.0 *00
0 0 *
00
O
0
6 cooqc?.
O
O
O
ar
00
O O
1-1
O
O
O O
O O
71rsi
O O
GC
00
0
'71
E
cu
cu
z
c:i
O
C
00
C
n-1
z
ce
*
—n
O
O
LI)
CI)
O
O
o
O
O
O
1.
cu
O
5'
c.)
dD
0
rj
U
O
71O
co
Pa1
00
1513
O
00
te.)
tr.)
te)
00
N
1.n1
cn
Cr)
1•••1
Cr)
c'f')
Jr-%
00
cn
C.14
00
O
O O
O
O
tri
0.4
cp
o0—
C
0
0
C4
W
8.
00
C4
a.)
N
O
O O O
CU
01.1
00
O
O
53
z
0
-41
the
(I)
4.)
4.)
0
00
0
00
;.14
cr)
e4g
,_, IN
•1- N
N s 0.
. o
e,i.
--
en
tt)
4
N
(-,i
cl,
O' (I .
cc
c?
o
6
rs-.
o ° 6 0
a)
en **
M
fl•
1
) Ce) M %.0CA
4 ''''
' c,-. ;
en
CA ON
N
N
dN
N
4 N
N
ON
co
O
0
o
c=>
N
en
8
O 9
0 c?
0 c0
CR
cr)
0
71- oo
ono°
6 o 6 6
•"4
0000
0 4= 0 0
NN
o N
0.4 "c4 n0
6 o 6 6
0
t.1
1Z‘
\C)
CA
0
0.)
U
EL'
ci)
0
z
t
o
crn
r--
Ooo
M
oo
nr:)
cs"
oro
en
en
tz4 0
0
C
0
71
0
4) "a
6
v? E
(1) E0 ..=0
N
o
9
0
ON ON 01 ON
0tuC14
a.)
,.c = _2 0
c/qP 1.• r4q c
ci.) d.) =0
a) ..0
t0 © = 0
Z Z cn° ri)
ci-o
Comi
4–•
44 Tu'
-c s..c ..=a)
a.)
V) CA V) V)
C.) C.) C-) (-)
V)
4..
't
(-4
OI
oo
O
a)
CID
c;
o
a)
N
E
a)
c;
Ca 0 8.
6 o 6 o
co
N
•er
0
kr)
el 0
0
O
V) V) V)
T.1
4.1
494 -4C -‹
ON
0
0
7i.
0.)
0.)
n
73
C.
ci,)
CI) i ..0
14
u? E
a.)
6 ••C E
0
CD
0 -C
= E
©
61 Z
4
O.)
= 0
0 ci)
cn
4.)
a)
0.1 c4 4..)
c.. C.
o o o o
C4 Eii cn V)
C...) C...) C.. .) C-)
V) V) V) CID
;m4 4-1 4.4 C.1-1
<4 -‹ -‹ d
a l';)
oa)
.=
a.)
a.)
n
E
=
=
0
1.1
0
Z o r4
CA
Z
Q Q Q
w. C. P. 0.
C o o o
EA c4 V)
C...) C...) C.) C.)
Ct) V) VD VI
T.•
Z
i
O
N
00
00
N
r-4
00
crs M
•er
93
00
O N
rti
01 en N
•Tr
N
0 0
CD.
•
0 0 (:)
N
O O
O
en 't
• s
O o
C1
C
O
r0.1
O
dF
•7r
N
O O
O O
O O
O
O
O
C
N 'et
to
O O
*
*
Cr)
*
*
0
t.
("81
o
O
41'
o
C;
6 6
N *
rn
0 0.
i 4.
c ;
N
01
O O
O CD.
O O cn
O
O
•er •er
O O O
O O
N
O
O O
-0
n.0
O
CT CT ∎CD ON
N Pel N cn
0 0 0 0
0 4? 0. 0.
OOo
oo 01 "ct
o
o
6 o 6 6
N e.i en
c)
0
O o 0
ei3 O 9 6
00
00
00
00
O
Le)
*
o
N 0N *
• c
oM
O
6 c3
CT CT ON CT
vnn
ei
=
O
01
V) GC V) V)
U
C.) C..) U
CI) CID CI) CA
.14 4. 4.
<4 'et < <4
.Ifi
c,
•—n
0
o
6
6
N
O
O
O O
00
7:1 = 74 cu
..0
CC
O
=:,
tu
c+. Cl• 4., 4_,
O 41.) cu 0
.0 -0
oo
N
N
6
c cu
P. c) P.
0
ea a.) -45 a)
a
,..a . = Q v, i ,.=
v) : v)
v
6
:
0e
e a)
6
0
0.) ts 0 ,E
4) - e
co -t
= 6 -E. z
:F t = 0
t 0 O 0
64 0 0 0
0 Z V)o V)
O C4
Z
Et. g
•71-
O
O
O
N
(:)`) N
If)
en
o
° r-: o –1
1
6 o 6 6 o 6
Cf) N
0 0 N
n—N•1 0 o in
6 '=: c! 6
O o
ca 0 a) cu
sa4 P4 P.
0 0 0 0
R•
VD
C.)U U U
CI) V) Ei)
CA CI) C4 V)
4.,
v., v..,
-04 < <4 <
Co)
Cn
C P..
m a) 7-0 a)
v' Q
c
..-. cu ° cu
.
0
6, ,1 . ) cg oe
44 .0 0 -0
,:s t -0 0
.i 0 0 0
C
iZ o CID
C4
Z
Cli) 0 0 0
Zto P. P. C:1
C 0 0 0
7) CI1 CA CID
.) U U U
;.T.
V) V) V)
4 Z Z
5
vo
vo
00
f4
kr,
t---
in
ei
cn
cg
'Tr
–,
ex:
en
t--:
en
∎6
8.
c?
Oo o o
Cn
O
(n1
N
•:t cn en
.
on
O o
O o = ©
©
o
o o c:
c?
6 c:; = 6 o
oo
O
cn
mtl•
cn
–
c:n
8 o
4::'
o o
t.--
ei
C:1
el
0
° 6
–I o
el 6 o
9 o
cn
*
,c;
In
o i - ,
o W =
O o c::
6 –4. c)
O\n
f•1 CD ,,,
r)
C
o
vn.4
trl
o
,-1
cl
o
4:'
6 ©
i.n
o
c?
o o
6
tr)
00
h
01
ce;
6 6 c:;
O
0\ 0\ C71
0
0.94
9'
0
3
4
Ea.)
a
)
l
V)
C
' c ,.c
V)
E
3) = <1.) .0
O
O
6
O
O
G;
ON
00
Cr)
en
o) al.,
Cl.
cl)
ce)
0
,, 1.9 71 49
= c;) = 0
0E6
: E
CU
a.) =
<24 =
=
= t =
0 o g
▪ t
0 "4-;'.
° Z 0 CI)
° Z =
0 C4
Z
v)
=
t
Z
4, 4, 4, CNo
u 13
7"
a.)
a.)
= ..0 ..= =
v) C/) v) v)
C..) C.) C.) C.)
V) V) V) CA
Ll.4
..et
1
cli
a) a) <14 a)
s:14 tz4 = cli
o o o o
EA EA cA c4
U C.) C.) C.)
C/1 Ci) V) V)
4.,.., -t <
0
ia,
© a
E
=
G)
-,I- 8 er;I a)
,..=
=
v)
ci;
E
CU 6 (1.)
0 =
CO =
= _ = 0
0 l'e 0
0 Z Z CID
0
Z
c)
cu a)
0.) a)
ci. t=t• sa.
C14
0 0 0 0
v)
c."-A
v) gi
C.) C.) C.) C.)
cf) r4 c4 V)
5
4 Z
a)
N
71:
er)
,-4
VD
cn
6
0;1
O
CY
bA
00
ICI
N
41•
Olt2
h
co
N
N
n
4=
cp
tr.)
t`11
a.)
04
cn
cx)
tr) n.o
o o
O o
o O .
6 6 °
4.)
fe)
O
CR
O
4 -1
O
O
4=
O
*
*
O
04
O
00 00
"L
O
0 en.
o
6
it
O
v)'-r
C 8
o
c q
6 9
0.4
L/)
*
L.)
o
=
c?
N
c?
c:
cz
°
°
n.©
O
O
O
O
O
O
O
O
O
z
0\ CA 01
C14 0
Eto
00
(41
0 CL4 0 CZ...
a.)
a a.)
a)
-01 ° "
,.=
=
..=
ri, I
1
1
C:
":
C",)
".*!
v'
CI)
.7 = Cili
6
E
E
a)
o
4
-1
o
0
6 0
cis
a) = a.) ..s
a) = 0) .c
.= t .E,-= t ..=
-z o -,.. 0
t 0 = :
0 Z o v=)
0 Z g c4
Tt
=
Z
0 -"
co
cn
. 4—, 4—• c4-+
cu a) a.) Iii
Z
cA
o a) a)
cu
r=14 01, 04 04
..= .= .c .=
CID V) CI) CI)
0 0 0 0
C/) C7) CA Eii
U U U C..)
V) V) CI) c4
C..) C....) C.) U
VD V) cA C/)
;14 44 4-4 44
<
< < i!t
44 44 44 44
<
-.t .et
<
0 CZ, © t:14
a)
a.)
—a ° -a a)
..=)
u
=
;
cln =
a 0 6
: a)
0.) -0
-c
v
.c t
=
t 0 -.4 o
0 Z g r.)
Z
cA
C
a.) au I4
0. 0, 1:14
0 0
a)
a
0 0
Cri E7) Z EA
U U C..) (...)
C/) V) V) CA
LT4