The Relative Importance of Fishing and the
Environment in the Regulation of Fish Population
Abundance
June 26-28, 2012
A Symposium of the American Institute of Fishery Research Biologists
Waypoint Event Center, Fairfield Inn and Suites
185 MacArthur Drive, New Bedford, Massachusetts 02740 USA
Symposium Sponsors: Massachusetts Division of Marine Fisheries; Southern New England Chapter
of the American Fisheries Society; University of Massachusetts School for Marine Science &
Technology, Department of Fisheries Oceanography; OceanTrust; National Marine Fisheries
Service; Fisheries and Oceans Canada; New Bedford Whaling Museum
AGENDA
Tuesday, June 26
8:00
On-Site Registration: Available until 9:00 AM.
9:00
Welcoming Remarks: Dr. Steve Cadrin, AIFRB President; Hon. Jon Mitchell, Mayor of New
Bedford; Paul Diodati, Director, Massachusetts Division of Marine Fisheries; and Dr. Bill
Karp, Acting Science and Research Director, Northeast Fisheries Science Center
10:00 Keynote Speaker: Harvesting in a Nonlinear World: Fisheries as Complex Systems.
Michael J. Fogarty, Northeast Fisheries Science Center, NOAA Fisheries Service, 166 Water
Street, Woods Hole, MA, 02543, USA
10:50 Coffee Break
Oral Presentations (Presenting Author Underlined)
11:10 Characterizing and Quantifying Mortality in the Early Life-stages of Marine Fish
Populations. R. Christopher Chambers, Northeast Fisheries Science Center, NOAA Fisheries
Service, Highlands, NJ, 07732, USA
11:30 Are Shifts in Marine Species' Ranges Predictable? Insights from Both Coasts of North
America. Malin L. Pinsky1, Michael Fogarty2, Boris Worm3, Jorge L. Sarmiento4, and Simon
A. Levin1, 1 Department of Ecology and Evolutionary Biology, 106A Guyot Hall, Princeton
University, Princeton, NJ, 08544, USA; 2 Northeast Fisheries Science Center, 166 Water St.,
Woods Hole, MA, 02543, USA; 3 Biology Department, Dalhousie University, Halifax, NS, B3H
4R2, Canada; 4 Atmospheric and Ocean Sciences, 300 Forrestal Road, Princeton University,
Princeton, NJ, 08544, USA
11:50 Cod Productivity Constrained at the Southern End of its Range in North America by
Cold Water Conditions. Kevin D. Friedland1, Joe Kane2, Jon Hare1, Gregory Lough3, Paula
S. Fratantoni3, Janet Nye3, Michael Palmer3, and Michael Fogarty3, Northeast Fisheries
Science Center, NOAA Fisheries Service, 1Narragansett, RI, USA; 2Sandy Hook, NJ, USA;
3
Woods Hole, MA, 02543, USA
12:10 Lunch Break
2:00
Building Strong Inference to Distinguish Fishing and Environmental Effects in a Datalimited Fishery. Richard S. McBride1, Angela B. Collins2, Seifu Seyoum2, and Michael
Tringali2, 1NOAA Fisheries, Northeast Fisheries Science Center, 166 Water Street, Woods
Hole, MA, 02543, USA; 2Florida Fish & Wildlife Conservation Commission, Fish & Wildlife
Research Institute, 100 8th Avenue SE, St. Petersburg, FL, 33701, USA
2:20
The Great Weakfish Boom and its Subsequent Suppression as a Response to the Decline
and Recovery of Striped Bass on the Mid-Atlantic Coast, with a Supporting Role for
Spiny Dogfish. Desmond M. Kahn1 and James M. Uphoff, Jr., 1Delaware Division of Fish and
Wildlife, P.O. Box 330, Little Creek, DE, 19961, USA; 2Maryland Fisheries Service,
Annapolis, MD, USA
1
2:40
Wasp Waist or Beer Belly? Modeling Food Web Structure and Energetic Control in
Alaskan Marine Ecosystems, with Implications for Fishing and Environmental Forcing.
Sarah Gaichas1, Kerim Aydin2, Stephani Zador2, and Ivonne Ortiz3, Northeast Fisheries
Science Center, NOAA Fisheries Service, Woods Hole, MA, USA; 2 Alaska Fisheries Science
Center, NOAA Fisheries Service, Seattle, WA, USA; 3 University of Washington, Seattle, WA,
USA
3:00
Sea Scallop (Placopecten magellanicus) Predation on the Northeast U.S. Continental
Shelf: Trends in Groundfish Feeding Habits. Stacy Rowe and Brian E. Smith,
NOAA/NMFS/NEFSC, Food Web Dynamics Program, 166 Water Street, Woods Hole, MA,
02543, USA
3:20
Coffee Break
3:40
Fishing for Answers: Using Diets of Angler-Caught Predators to Assess Foodweb
Changes in Lake Huron, 2009-2011. Ethan Bright1,2, Edward F. Roseman2, Jeffrey Schaeffer2
and David G. Fielder3,1School of Natural Resources and Environment, University of Michigan,
440 Church St., Ann Arbor, MI, 48109-1041, USA; 2 US Geological Survey, Great Lakes
Science Center, 1451 Green Rd., Ann Arbor, MI, 48105, USA; 3 Michigan Department of
Natural Resources, Alpena Fisheries Research Station, 160 E. Fletcher, Alpena, MI, 49707,
USA
4:00
Integrating, and then Disentangling, Multiple Drivers Impacting Living Marine
Resources: I. Jason Link, Northeast Fisheries Science Center, NOAA Fisheries Service, 166
Water Street, Woods Hole, MA, 02543, USA
4:20
Discussion on Ecological Effects (Moderated by Brian Rothschild)
5:00
Break
6:00
Cocktail Reception at the New Bedford Whaling Museum
8:00
Presentation of AIFRB Outstanding Achievement Award
2
Wednesday, June 27
8:00
On-Site Registration: Available until 9:00 AM.
9:00
Opening Remarks: Dr. Richard Beamish
9:10
Keynote Speaker: The role of the environment and harvest on stock status: contrasting
California salmon and rockfish fisheries. Churchill Grimes, John Field, Steve Lindley, Alec
MacCall, Steve Ralston and Brian Wells, National Marine Fisheries Service, Southwest
Fishery Science Center, Santa Cruz, CA,USA
Oral Presentations (Presenting Author Underlined)
10:00 Pink Salmon Catches Throughout the Northern Pacific Continue to Set Record Highs
Because of Climate… and Hatcheries. Richard Beamish, Department of Fisheries and
Oceans, Nanaimo BC, Canada
10:20 When, Where, and Sometimes Why: Environmental Effects on Longfin Inshore Squid
Distribution and Implications for Fisheries Management. Owen C. Nichols, School for
Marine Science and Technology, University of Massachusetts – Dartmouth, 200 Mill Road –
Suite 325, Fairhaven, MA, 02719, USA
10:40 Integrating, and then Disentangling, Multiple Drivers Impacting Living Marine
Resources: II. Jason Link, Northeast Fisheries Science Center, NOAA Fisheries Service, 166
Water Street, Woods Hole, MA, 02543, USA
11:00 Coffee Break
11:20 Theories on the Influence of Environment on Atlantic Sea Scallop Distribution,
Abundance and Recruitment. Kevin D. E. Stokesbury and Bradley P. Harris, School for
Marine Science and Technology, University of Massachusetts – Dartmouth, 200 Mill Road –
Suite 325, Fairhaven, MA, 02719, USA
11:40 Effects of Climate Change on Fisheries Yields of Large Marine Ecosystems. Kenneth
Sherman, NMFS-NOAA Narragansett Laboratory, Narragansett, RI, USA
12:00 The Utility of Environmental Predictors of Catch to Reduce Bycatch in the Northwest
Atlantic Mid-Water Trawl Fishery. N. David Bethoney, Kevin D. E. Stokesbury and Steven
X. Cadrin, School for Marine Science and Technology, University of Massachusetts –
Dartmouth, 200 Mill Road – Suite 325, Fairhaven, MA, 02719, USA
12:20 Lunch Break
2:00
Evaluating Environmental Influence and Maturity on Growth and Subsequent
Recruitment Dynamics in Georges Bank Haddock (Melanogrammus aeglefinus). Mark
Wuenschel1, Sandra Sutherland1, Richard McBride1, Elizabeth Brooks and Kevin Friedland2,
1
National Marine Fisheries Service, Northeast Fisheries Science Center, 166 Water Street,
Woods Hole, MA, 02543-1026, USA; 2National Marine Fisheries Service Northeast Fisheries
Science Center, Narragansett Laboratory, 28 Tarzwell Drive, Narragansett, RI, 02882-1152,
USA
3
2:20
Effect of a Changing Thermal Regime on Settlement Dynamics of Postlarval
American Lobster, Homarus americanus, in Southern New England. Kelly A. Whitmore1
and Robert P. Glenn2, Massachusetts Division of Marine Fisheries,130 Emerson Ave,
Gloucester, MA, 01930, USA; 21213 Purchase Street, New Bedford, MA, 02740, USA
2:40
Environmental Monitors on Lobster Traps: Fishermen Contributing to our Ocean
Observing Systems. James Manning, Northeast Fisheries Science Center, NOAA Fisheries
Service, 166 Water Street, Woods Hole, MA, 02543, USA
3:00
Effects of Fishing and Winter Temperature on Spotted Seatrout Survival. Timothy A.
Ellis1, Jeffrey A. Buckel1, and Joseph E. Hightower2, 1Center for Marine Sciences and
Technology, Department of Biology, North Carolina State University, 303 College Circle,
Morehead City, NC, 28557, USA; 2U. S. Geological Survey, North Carolina Cooperative Fish
and Wildlife Research Unit, North Carolina State University, Department of Biology, Campus
Box 7617, Raleigh, NC, 27695, USA
3:20
Coffee Break
3:40
Discussion on Environmental Factors (Moderated by Brian Rothschild)
4:20
Whaleboat Races
7:00
Symposium Dinner (Inner Bay Bar & Grille Restaurant, 1339 Cove Road, New Bedford)
4
Thursday, June 28
8:00
On-Site Registration: Available until 9:00 AM.
9:00
Opening Remarks: Dr. Brian Rothschild
9:10
Keynote Speaker: Rebuilding Fish Communities: The Ghosts of Fisheries Past and the
Virtue of Patience. Jeremy Collie1, Marie-Joëlle Rochet2, and Richard Bell1, 1University of
Rhode Island, Graduate School of Oceanography, Narragansett, RI, 02882, USA; 2 IFREMER,
Département EFH, B.P. 21105, 44311 Nantes CEDEX 03, France ; jcollie@gso.uri.edu
Oral Presentations (Presenting Author Underlined)
10:00 Consideration of Fishing and the Environment in Rebuilding Plans. Steven X. Cadrin,
School for Marine Science and Technology, University of Massachusetts – Dartmouth, 200
Mill Road – Suite 325, Fairhaven, MA, 02719, USA
10:20 Re-evaluation of the Threshold to Allow a Fishery in Light of Changes in Recruitment
and Survival Due to Whales, Disease, and the Environment. Terrance J. Quinn II1, Suzanne
F. Teerlink1, and Steven D. Moffitt2, 1Juneau Center, School of Fisheries and Aquatic
Sciences, University of Alaska Fairbanks, Juneau, AK, USA; 2Alaska Department of Fish and
Game, Cordova, AK, USA
10:40 Impacts of Ghost Fishing from American Lobster Traps. Derek Perry1, Kelly Whitmore2,
and Robert Glenn1, 1Massachusetts Division of Marine Fisheries, Invertebrate Fisheries
Program, 1213 Purchase Street, New Bedford, MA, 02744, USA; 2Massachusetts Division of
Marine Fisheries, Invertebrate Fisheries Program, 30 Emerson Ave., Gloucester, MA, 01930,
USA
11:00 Coffee Break
11:20 Patterns in Eastern Bering Sea Pollock Fishery Catch Rates Relative to Assessment and
Quota Recommendations. James Ianelli and Steven Barbeaux, Resource Ecology and
Fisheries Management Division, Alaska Fisheries Science Center, NMFS/NOAA, Seattle, WA,
98115, USA
11:40 Incorporating Environmental Effects in Stock Assessments: Methods, Limitations, and
Future Directions. Michael J. Wilberg, Chesapeake Biological Laboratory, University of
Maryland Center for Environmental Science, USA
12:00 The Northwest Atlantic Large-Fish Transition of the 1980s and the Identifiability
Problem. Brian Rothschild and Y. Jiao, School for Marine Science and Technology, University
of Massachusetts – Dartmouth, 706 South Rodney French Boulevard, New Bedford, MA,
02744, USA
12:20 Lunch Break
5
2:00
Delineating Ecosystem Overfishing: Analysis of Fishing Pressure and Environmental
Thresholds for Ecological Indicators. Scott I. Large, Gavin Fay, Kevin Friedland, and Jason
S. Link, Northeast Fisheries Science Center, NMFS, Woods Hole, MA, 02543, USA
2:20
The “Butterfish Smackdown”: Steps Toward the Development of an Operational
Seascape Ecology in Support of Ecosystem Management. John Manderson1, Josh Kohut2,
Greg DiDomenico3, and John Hoey4, 1Northeast Fisheries Science Center - Behavioral
Ecology, USA; 2Rutgers University, USA; 3Garden State Seafood Association; 4Northeast
Fisheries Science Center - Cooperative Research, USA
2:40
Length Related Capture of Fish by Otter Trawls: The Effect of Water Temperature and
Tow Duration. Pingguo He, School for Marine Science and Technology, University of
Massachusetts – Dartmouth, 706 South Rodney French Boulevard, New Bedford, MA, 02744,
USA
3:00
Science, Sustainability and the Environment. Thor Lassen, Ocean Trust, 11921 Freedom
Dr. Ste. 550, Reston, VA, 20190, USA
3:20
Discussion on Management Implications (Moderated by Steve Cadrin)
4:00
Closing Remarks
6
ABSTRACTS
Pink Salmon Catches Throughout the Northern Pacific Continue to Set Record Highs Because of
Climate… and Hatcheries. Richard Beamish, Department of Fisheries and Oceans, Nanaimo BC,
Canada; beamishr@pac.dfo-mpo.gc.ca
Commercial catches of Pacific salmon set a record high in 1995, again in 2007 and then again in 2009.
Pink salmon are the major contributor to the catch, representing 67% in numbers and 48% in weight.
Pink salmon are unique among Pacific salmon with a fixed two year life cycle. As a consequence,
populations are isolated by their spawning year and are identified as spawning in years ending in odd
or even numbers. Immediately after the 1977 climate regime shift, abundances of pink salmon
increased throughout the subarctic Pacific. At the same time, hatcheries started to increase their
releases of pink salmon. Today, hatcheries release about 1.3 billion fry or about 10% of all wild pink
salmon fry. From the early 1990s to the present, only pink salmon spawning in odd-year numbered
years continued to increase in abundance, while abundances of even-year pink salmon showed no
trend. Thus, the historic high catches are occurring only in odd numbered years. A possible
explanation is that the odd-year pink salmon are more dependent on finding food in the winter that
even-year pink salmon. The odd-year pink salmon therefore are better adapted to an increasing food
supply in the winter that results from a general warming of the ocean.
The Utility of Environmental Predictors of Catch to Reduce Bycatch in the Northwest Atlantic
Mid-Water Trawl Fishery. N. David Bethoney, Kevin D. E. Stokesbury and Steven X. Cadrin,
School for Marine Science and Technology, University of Massachusetts – Dartmouth, 200 Mill Road
– Suite 325, Fairhaven, MA, 02719, USA; nbethoney@umassd.edu
The incidental catch of river herring (Alosa pseudoharengus, A. aestivalis) and American shad (A.
sapidissima) by mid-water trawl vessels targeting Atlantic herring (Clupea harengus) and mackerel
(Scomber Scombrus) has become an issue of concern for the conservation of river herring and shad.
All five species undertake predictable, seasonal migrations in the northwest Atlantic Ocean. Seasonal
distributions overlap during the winter and fall leading to increased bycatch rates with the most
bycatch occurring in the winter. The distinct seasonal movement of these fishes suggests they may be
employing habitat selection while at sea by choosing areas that maximize individual fitness. Previous
studies identified different, specific temperature, depth, and other environmental preferences linked to
the distribution of these fishes at sea. The goal of this study is to test if oceanographic features that
indicate the probability of large catches of each species can be used to reduced bycatch in the midwater trawl fishery. To identify environmental associations, the frequency of catch in the National
Marine Fisheries Service winter bottom trawl survey (2000-2009) for intervals of in-situ
environmental measurements was compared to a uniform probability. The utility of this information to
reduce bycatch was then assessed by comparing the variables and ranges each species was associated
with. In addition, these associations were tested using the Northeast Fisheries Observer Program midwater trawl dataset joined to Finite-Volume Coastal Ocean Model environmental information. This
dataset was used to quantify how much bycatch and target catch was within predicted environmental
conditions.
7
Fishing for Answers: Using Diets of Angler-Caught Predators to Assess Foodweb Changes in
Lake Huron, 2009-2011. Ethan Bright1,2, Edward F. Roseman2, Jeffrey Schaeffer2 and David G.
Fielder3,1School of Natural Resources and Environment, University of Michigan, 440 Church St., Ann
Arbor, MI, 48109-1041, USA; 2 US Geological Survey, Great Lakes Science Center, 1451 Green Rd.,
Ann Arbor, MI, 48105, USA; 3 Michigan Department of Natural Resources, Alpena Fisheries
Research Station, 160 E. Fletcher, Alpena, MI, 49707, USA; ethanbr@umich.edu
We analyzed diets of 6,935 angler-caught predator fish from Lake Huron during 2009-2011 to
measure predator response to recent declines in biomass and composition in the prey base, especially
the near absence of Alewife. Anglers captured primarily Chinook Salmon, Lake Trout, Walleye,
Steelhead, and Atlantic Salmon. During this study, pelagic prey fish were scarce and predator diets
varied. While Lake Trout consumed primarily Round Goby and small Rainbow Smelt, recently
stocked Lake Trout and Chinook Salmon comprised a substantial proportion of their diets, and were
occasionally the most prominent prey observed in stomachs after stocking events. Most Chinook
Salmon were collected from northern Lake Huron and consumed pelagic prey fishes with Rainbow
Smelt dominating their diets. Steelhead and Atlantic Salmon had broad diets that contained benthic
and pelagic prey fishes as well as large contributions of terrestrial and aquatic invertebrates. Most
Walleye were collected from Saginaw Bay and ate mostly Emerald Shiners, Round Gobies, Yellow
Perch and Mayflies. Diets of predators in Lake Huron differed vastly from those examined during a
similar study in the 1980s when Alewife and Rainbow Smelt were prevalent. In this study, predators
appeared to be prey-limited, and large-bodied prey seemed especially rare. Prey limitation may be
most severe for Chinook Salmon, and Lake Trout, because their diet breadth was narrow. Atlantic
Salmon, Steelhead and Walleye may be less affected because of their wider diet breadth and may have
an advantage in low-prey scenarios, especially when large bodied pelagic prey are lacking. These
results should be considered by fishery managers when developing future stocking scenarios for Lake
Huron.
Consideration of Fishing and the Environment in Rebuilding Plans. Steven X. Cadrin, School for
Marine Science and Technology, University of Massachusetts – Dartmouth, 200 Mill Road – Suite
325, Fairhaven, MA, 02719, USA; scadrin@umassd.edu
Productivity of fishery resources is influenced by both fishing and environmental factors, and
rebuilding plans depend on both reductions in fishing and environmental conditions. The approach to
rebuilding plans varies among fishery management systems. At one extreme, some systems that
require rigid rebuilding schedules (e.g., 10 years) and rebuilding targets (e.g., BMSY) such as the US
Magnuson Stevens Fishery Conservation and Management Act. An intermediate approach is a harvest
control rule that limits catch or fishing mortality as a function of stock size relative to a threshold stock
size, thereby decreasing the negative influence of the fishery on the stock, but not imposing a
rebuilding schedule or target (e.g., the ICES MSY framework). At the opposite extreme are systems
that attempt to achieve modest stock increases each year depending on prevailing conditions (e.g.,
US/Canada Transboundary Management Governance Committee). Simulations based on a range of
stock productivities, random environmental variation and scientific uncertainty were used to evaluate
performance of alternative rebuilding plans for achieving maximum sustainable yield and avoiding
low stock size. Rebuilding plans performed significantly better than a simple FMSY strategy with no
rebuilding requirements, but the three alternative rebuilding strategies performed similarly. In theory,
stocks will eventually rebuild when fished at FMSY, but reducing fishing mortality further when stock
size is low appears to help achieve optimum yield.
8
Characterizing and Quantifying Mortality in the Early Life-stages of Marine Fish Populations.
R. Christopher Chambers, Northeast Fisheries Science Center, NOAA Fisheries Service, Highlands,
NJ, 07732, USA; chris.chambers@noaa.gov
The abundance of a population is set by the difference between augmentation and losses of
individuals. In most marine fish populations the gains and losses are due to reproduction and
mortality, respectively. We are concerned here with the losses due to mortality that occur in the early
life-stages and especially their magnitudes, causes, and evidence of whether or not these losses covary
with population density. The magnitude of mortality during the egg, larval, and early juvenile lifestages are particularly difficult to accurately quantify in situ for marine fish populations due to the
scale and heterogeneity of the population relative to our ability to sample it. Identifying the causes of
mortalities is similarly challenging due to the fact that losses are not usually observed directly but are
estimated by reduction in the number of survivors. Here we i) summarize methods used to estimate
mortality and its proxies, ii) assess patterns in the estimates and time courses of mortality, iii) identify
common direct and indirect causes of mortality, and iv) evaluate evidence that mortality is density
dependent. We use this approach of identifying, parsing, and evaluating patterns in mortality in order
to provide a prescription for improved understanding of mortality in the early life-stages of marine
fishes and its role in population regulation.
Rebuilding Fish Communities: The Ghosts of Fisheries Past and the Virtue of Patience. Jeremy
Collie1, Marie-Joëlle Rochet2, and Richard Bell1, 1University of Rhode Island, Graduate School of
Oceanography, Narragansett, RI, 02882, USA; 2 IFREMER, Département EFH, B.P. 21105, 44311
Nantes CEDEX 03, France; jcollie@gso.uri.edu
The ecosystem approach to management requires the status of individual species to be considered in a
community context. We conducted a comparative ecosystem analysis of the Georges Bank and North
Sea fish communities to determine the extent to which biological diversity is restored when fishing
pressure is reduced. First, we characterized the timing and intensity of the fishing and environmental
drivers acting on these two fish communities. Second, standardized bottom-trawl survey data were
used to investigate the temporal trends in community metrics. Third, a size-based, multispecies model
(LeMans) was used to test the response of community metrics to both simulated and observed changes
in fishing pressure in the two communities. These temperate North Atlantic fish communities have
much in common, including a history of overfishing. In recent decades fishing pressure has been
reduced and some species have started to rebuild. The Georges Bank fishery has been more selective
and fishing pressure was reduced sooner. The two communities have similar levels of size diversity
and biomass per unit area, but fundamentally different community structure. The North Sea is
dominated by small species and has low evenness. Georges Bank has higher abundance of noncommercial species. These fundamental differences in community structure are not explained by the
contemporary fishing patterns. The multispecies model was able to predict the observed changes in
community metrics better on Georges Bank, where rebuilding is more apparent than in the North Sea.
Model simulations revealed hysteresis in rebuilding community metrics toward their unfished levels,
particularly in the North Sea. Species in the community rebuild at different rates, with smaller prey
species greatly outpacing their large predators and overshooting their pre-exploitation abundances.
This indirect effect of predator release delays the rebuilding of community structure and biodiversity.
Therefore community rebuilding is not just the sum of single-species rebuilding plans. Different or
additional management strategies will be needed to restore biodiversity and community structure.
9
Effects of Fishing and Winter Temperature on Spotted Seatrout Survival. Timothy A. Ellis1,
Jeffrey A. Buckel1, and Joseph E. Hightower2, 1Center for Marine Sciences and Technology,
Department of Biology, North Carolina State University, 303 College Circle, Morehead City, NC,
28557, USA; 2U. S. Geological Survey, North Carolina Cooperative Fish and Wildlife Research Unit,
North Carolina State University, Department of Biology, Campus Box 7617, Raleigh, NC, 27695,
USA; taellis@ncsu.edu
Spotted seatrout (Cynoscion nebulosus) are frequently the most targeted marine species by recreational
fishers in North Carolina each year. The state’s recent assessment concluded the population is
overfished; however, the extent to which variability in natural mortality (M), particularly during
winter, affects annual estimates of fishing mortality (F) is unknown. This is potentially important for
spotted seatrout in North Carolina because they are near the northern extent of their geographic range.
We are using data from the first comprehensive tag-return and telemetry study of spotted seatrout in
North Carolina to directly estimate F and M. We conducted both laboratory and field studies to obtain
estimates of auxiliary parameters (e.g., reporting rate, tag retention, and tagging-induced mortality)
necessary for our tag-return modeling. There was no mortality associated with conventional or
telemetry tagging but reporting rate and tag loss of conventional tags significantly limited returns in
our study. From 2008 to 2012, our preliminary tag-return estimates indicate that bimonthly
instantaneous rates ranged from 0.004 to 0.045 for F, and from zero to 1.750 for M. Water
temperature strongly influenced M of telemetered spotted seatrout; M increased abruptly at
temperatures below approximately 6°C. Direct telemetry-based estimates of monthly M during winter
in a single region of the state were high and similar to those estimated indirectly by our tag-return
experiment that was conducted throughout the state. Our annual estimates of F were lower and M
higher than those reported for spotted seatrout in North Carolina’s recent age-based stock assessment,
where M was both fixed and indirectly estimated through weight-based parameters and longevity.
Future assessments of spotted seatrout in North Carolina would be improved by consideration of more
direct estimates of and annual variability in M.
Harvesting in a Nonlinear World: Fisheries as Complex Systems. Michael J. Fogarty, Northeast
Fisheries Science Center, NOAA Fisheries Service, 166 Water Street, Woods Hole, MA, 02543, USA;
Michael.Fogarty@noaa.gov
Coupled human-resource systems are increasingly recognized as a globally prevalent form of complex
adaptive system characterized by nonlinear dynamics and the potential for rapid shifts in the state of
the resource. This perspective is steadily gaining traction in framing approaches to ecosystem-based
management. Models currently used in traditional fisheries management typically assume a
monotonic decomposable system in which the effects on system dynamics of interacting factors are
separable. Most of these models also assume a system characterized by globally stable dynamics.
Here management models admitting multiple stable states or unstable (chaotic) system dynamics are
reviewed and the implications of non-decomposable systems involving the interaction of
environmental and human-related impacts are explored. It is shown that lack of correlation does not
imply lack of causation in such systems and that ephemeral (mirage) correlations are to be expected,
providing one explanation for the common failure of fishery-environmental correlations. These results
hold important implications for traditional analyses examining the effect of environmental factors in
coupled human-natural systems. Both parametric and nonparametric modeling frameworks are
considered and the value of the latter in addressing model uncertainty in complex systems is
demonstrated. Newly developed methods in phase-space reconstruction for univariate and
multivariate time series analysis and capable of dealing with nonlinear system dynamics are described.
Applications of these methods to fishery systems to address short term forecasting needs, assessing
10
dynamical coupling, and establishing functional relationships in multispecies communities are
illustrated. It is shown that coupled human-natural systems reflect a layered complexity in which the
effects of human activities superimposed on ecological processes increase the probability of nonlinear
dynamics in these systems.
Cod Productivity Constrained at the Southern End of its Range in North America by Cold
Water Conditions. Kevin D. Friedland1, Joe Kane2, Jon Hare1, Gregory Lough3, Paula S. Fratantoni3,
Janet Nye3, Michael Palmer3, and Michael Fogarty3, Northeast Fisheries Science Center, NOAA
Fisheries Service, 1Narragansett, RI, USA; 2Sandy Hook, NJ, USA; 3Woods Hole, MA, 02543, USA;
kevin.friedland@noaa.gov
The Northeast Shelf Large Marine Ecosystem is experiencing a period of increasing temperature levels
and range, which is impacting the quantity of thermal habitats within the ecosystem. With increasing
temperatures, warm water thermal habitats (16-27°C) have increased while there has been a reciprocal
decline in cool water habitats (5-15°C). These cool water habitats are the most abundant and thus
comprise the core habitats of the ecosystem. However, the coldest thermals habitats (1-4°C) have
increased or remained constant, reflecting a discontinuity in the progression of warming along a
latitudinal gradient. This discontinuity may be the result of recent changes in the circulation of water
masses in the northern Gulf of Maine, notable changes associated with the Labrador Current. The
contraction of core thermal habitats appears to have had biological consequences on multiple trophic
levels. In particular, two zooplankton species associated with the larval feeding of Atlantic cod,
Gadus morhua, have declined in abundance in spatially discrete areas where cod populations have
failed to respond to stock recovery measures. The zooplankton species group Pseudocalanus spp,
which is associated with winter spawning cod, has declined on Georges Bank and in the Eastern Gulf
of Maine. The zooplankton Centropages typicus has declined in the Gulf of Maine during fall,
potentially affecting spring spawning cod in that area. These observations are consistent with the
hypothesis that portions of the population complex of cod are suffering reduced reproductive
productivity due to thermally induced changes in zooplankton abundance.
Wasp Waist or Beer Belly? Modeling Food Web Structure and Energetic Control in Alaskan
Marine Ecosystems, with Implications for Fishing and Environmental Forcing. Sarah Gaichas1,
Kerim Aydin2, Stephani Zador2, and Ivonne Ortiz3, Northeast Fisheries Science Center, NOAA
Fisheries Service, Woods Hole, MA, USA; 2 Alaska Fisheries Science Center, NOAA Fisheries
Service, Seattle, WA, USA; 3 University of Washington, Seattle, WA, USA; sgaichas@gmail.com
The Eastern Bering Sea (EBS) and Gulf of Alaska (GOA) continental shelf ecosystems show some
similar and some distinctive groundfish biomass dynamics between areas. Given that similar species
occupy these regions and fisheries management is also comparable, similarities might be expected, but
to what can we attribute the differences? Different types of ecosystem structure and control (e.g. topdown, bottom-up, mixed) can imply different ecosystem dynamics and climate interactions. Further,
the structural type identified for a given ecosystem may suggest optimal management for sustainable
fishing. Here, we use information on the current system state derived from food web models of both
the EBS and the GOA combined with dynamic ecosystem models incorporating uncertainty to classify
each ecosystem by its structural type. We then suggest how this structure might be generally related to
dynamics and predictability, as well as potential climate influence. We find that the EBS and GOA
have fundamentally different food web structure both overall, and when viewed from the perspective
of the same commercially and ecologically important species in each system, walleye pollock
(Theragra chalcogramma). Structural qualities of the EBS food web centered on a large mass of
pollock appear to contribute to relative system stability and predictability, whereas the structure of the
11
GOA food web with high predator biomass contributes to a more dynamic, less predictable ecosystem.
Mechanisms for climate influence on pollock production in the EBS are increasingly understood,
perhaps contributing further to predictability in this system. In contrast, climate forcing mechanisms
contributing to the potentially destabilizing high predator biomass in the GOA remain enigmatic; here
spatial considerations may be important, as in the neighboring Aleutian Islands ecosystem. Overall,
our results suggest that identifying structural properties of fished food webs is as important for
sustainable fisheries management as attempting to predict climate effects within each ecosystem.
The role of the environment and harvest on stock status: contrasting California salmon and
rockfish fisheries. Churchill Grimes, John Field, Steve Lindley, Alec MacCall, Steve Ralston and
Brian Wells, National Marine Fisheries Service, Southwest Fishery Science Center, Santa Cruz,
CA,USA; brian.wells@noaa.gov
The California Current Ecosystem is strongly environmentally driven, and along with its included
fishery resources, subject to unpredictable low frequency environmental variability. While high
frequency variation, e.g., seasonal, is modest and predictable, low frequency variation, e.g., El Nino
and the Pacific Decadal Oscillation, is high and unpredictable. Thus, ocean conditions favorable for
survival and recruitment (timing and magnitude of upwelling and primary and secondary production;
circulation that transports larvae to or retains larvae near suitable settlement or rearing habitat) are
equally unpredictable, and fish species have life-history strategies that help them cope. Rockfishes
exhibit long life, slow growth and extreme iteroparity to compensate for infrequent strong recruitment,
and are thus inherently low productivity species unable to withstand high rates of exploitation.
Anadromous Chinook salmon, which are semelparous and short lived, exhibit local adaptation to
favorable spawning conditions in freshwater and the ability to use a variety of habitat types for rearing
in fresh water in California's Central Valley. Diverse environmental conditions have allowed for the
evolution of four distinct runs of Central Valley Chinook (fall, spring, winter and late fall). In addition
to run timing, local adaptations include timing and duration of freshwater rearing and out migration
timing. The resulting variability in size and timing of ocean entry act as hedges against a mismatch in
the timing of juvenile out migration and favorable ocean conditions for survival. Older/larger out
migrants are better able to withstand poor ocean conditions and variable out migration timing assures
that some out migrants will encounter favorable conditions. Anthropogenic changes in the Central
Valley have effectively eliminated all but the main stem spawning fall run (which is heavily
subsidized with hatchery production), thus drastically reducing the overall resilience of the stock
complex. Harvest is now precariously dependent upon only the fall run and its variable success in
encountering favorable conditions for production.
Length Related Capture of Fish by Otter Trawls: The Effect of Water Temperature and Tow
Duration. Pingguo He, School for Marine Science and Technology, University of Massachusetts –
Dartmouth, 706 South Rodney French Boulevard, New Bedford, MA, 02744, USA; phe@umassd.edu
Capture of fish by commercial and survey trawls involves herding of fish by bridles and sand clouds,
exhaustion at the mouth of trawl, and retention by or escape from the codend. During the capture and
escape process, the swimming ability plays an important role in the fate of the animal. The two most
important factors affecting the speed and endurance of swimming are water temperature and fish size.
In many species, including important groundfish species in the North Atlantic, swimming capacity
(speed and endurance) is reduced at lower water temperatures. Larger fish usually have better
swimming capacity than smaller fish of the same species. This paper will review swimming capacity
of fish, and explore how water temperature, towing speed and tow duration may affect catch rates and
12
size selection in commercial and survey trawls. The tendency of different selectivity between the
largest and the smallest fish due to environmental factors (such as temperature) and operational
parameters (such as towing speed and tow duration) has important implications for stock assessment
and fishery management.
Patterns in Eastern Bering Sea Pollock Fishery Catch Rates Relative to Assessment and Quota
Recommendations. James Ianelli and Steven Barbeaux, Resource Ecology and Fisheries
Management Division, Alaska Fisheries Science Center, NMFS/NOAA, Seattle, WA, 98115, USA;
jim.ianelli@noaa.gov
In the latter half of the 2011 pollock fishing season in the Eastern Bering Sea the commercial fishery
catch rates declined substantially. This raises concerns about the interaction with environmentally
driven factors that appear to affect fish distribution. In particular, fish aggregations can become more
dispersed and extend outside the range of the management and survey area. Results indicate that even
with extensive assessment data, accounting for such process errors inflates the uncertainty in stock
assessment results. From the fishery management perspective, a growing list of external constraints
(e.g., area closures and bycatch limits) combined with increased fuel costs complicates finding
effective solutions. We examine alternative hypotheses that led to the decline in fishing conditions
during the end of the 2011 fishing season including stock estimation errors and how management
measures may have contributed to the poorer fishing conditions. Results indicate that environmental
conditions played an important role in fishing conditions and the ability to provide accurate population
estimates.
The Great Weakfish Boom and its Subsequent Suppression as a Response to the Decline and
Recovery of Striped Bass on the Mid-Atlantic Coast, with a Supporting Role for Spiny Dogfish.
Desmond M. Kahn1 and James M. Uphoff, Jr., 1Delaware Division of Fish and Wildlife, P.O. Box 330,
Little Creek, DE, 19961, USA; 2Maryland Fisheries Service, Annapolis, MD, USA;
Desmond.kahn@state.de.us
Changes in abundance of predators and competitors can drive changes in stock productivity, which, in
turn, can drive fishery landings. Weakfish commercial landings on the Mid-Atlantic coast began a
steep increase in the early 1970s, increasing by 800% by 1981. The fishery was unregulated, and
landings then declined. Coastwide regulations enacted by 1995 restricted commercial effort and
minimum sizes and imposed recreational creel limits. Landings began to increase again until 2000,
but then declined consistently and are now the lowest on record. Virtual population analysis via
ADAPT indicated that F had begun to increase in 1995, just when regulations restricting fishing went
into effect. This result, based on an assumption of constant natural mortality, was rejected by the
assessment team because trends in relative fishing mortality showed no increase from 1995 through
the present. The assessment concluded that, in fact, natural mortality had increased beginning in 1995,
while F had remained flat. Use of Steele-Henderson surplus production modeling with predator terms
led to the hypothesis that the steep decline in Chesapeake Bay striped bass stocks in the 1970s
followed by their recovery through the 1990s, along with the restoration of the Delaware River
spawning stock of striped bass, was the driver of weakfish expansion and decline through predation
and probable competition for Atlantic menhaden. The more recent explosion of spiny dogfish on the
Mid-Atlantic coast has increased the predation pressure on weakfish on overwintering grounds off
North Carolina.
13
Delineating Ecosystem Overfishing: Analysis of Fishing Pressure and Environmental Thresholds
for Ecological Indicators. Scott I. Large, Gavin Fay, Kevin Friedland, and Jason S. Link, Northeast
Fisheries Science Center, NMFS, Woods Hole, MA, 02543, USA; scott.large@noaa.gov
Both fishing and environmental forces influence the structure of marine ecosystems. To implement an
ecosystem approach to fisheries and to understand marine ecosystems, an evaluation of ecological
indicators is warranted. To use ecological indicators in this context, it is important to understand the
relative contributions of fishing pressure and the environment, and particularly to identify inflection
points where these drivers significantly influence ecological indicators. We empirically determined
thresholds where environmental forces (i.e., AMO and SST) and fishing pressure significantly
influenced the response of ecological indicators for the Northeast U.S. large marine ecosystem. We
used Generalized Additive Models (GAMs) to predict a best fit line for univariate comparisons
between drivers and response indicators. With this fitted line, parametric bootstrap replicates were
used to establish 95 % confidence intervals (CI) for estimated first (i.e., slope, or short-term trend) and
second (i.e., inflection, or threshold) derivatives for each univariate comparison. A significant trend or
threshold was noted when first or second derivative CI passed beyond zero, allowing us to delineate
the level at which drivers influence the rate and direction of ecosystem indicators. We identify
reference levels where environmental forces and fishing pressure result in ecosystem change by
looking at aggregated responses of multiple ecological indicators. By extending this approach into the
multivariate, evaluation of simultaneous and relative effects of different drivers impacting these
thresholds was elucidated. Identifying trends and thresholds on aggregate ecosystem properties is
important in establishing the foundation for a more holistic basis for managing fisheries.
Science, Sustainability and the Environment. Thor Lassen, Ocean Trust, 11921 Freedom Dr. Ste.
550, Reston, VA, 20190, USA; tjlassen@yahoo.com
Ocean Trust in cooperation with members of the American Institute of Fishery Research Biologists
initiated a forum in 2010 to begin a dialog between major end users of seafood and the fishery
research community to discuss sustainability issues and needs of the seafood community. During our
first forum, several presenters referenced environmental change in the ocean environment as important
factors for prey and target species of interest. The 2012 forum on science and sustainability also
included some discussion of environmental variability in fish population dynamics. These
presentations drew much interest from the seafood community participants and highlighted the
importance of incorporating environmental factors as more routine part of fishery dynamics profiles.
The scientific community is challenged to provide an explanation for dramatic shifts in ecosystems.
Communication is another key challenge and responsibility that the seafood industry wants from
fishery scientists for support and clarification on issues of sustainability of fishery resources in a
dynamic ocean environment.
14
Integrating, and then Disentangling, Multiple Drivers Impacting Living Marine Resources: I-II.
Jason Link, Northeast Fisheries Science Center, NOAA Fisheries Service, 166 Water Street, Woods
Hole, MA, 02543, USA; jason.link@noaa.gov
Debates over which processes most strongly impact fish (and other living marine resource)
populations have celebrated their centennial (at least) anniversaries. Be it Hjort’s hypotheses, the
Thompson- Burkenroad debate, or Schaeffer’s third tier, clearly debating this topic has long been
important in fisheries science and management. As we move towards broader ocean-use and within
sector management, demands to evaluate a broader range of processes are only going to increase.
Based upon a mini-review of empirical work, I note how each facet among the triad of drivers has
been demonstrated to notably influence living marine resource populations. Environmental forcing,
trophodynamics, or exploitation have all driven the dynamics of these stocks at some point or in
certain situations. More so, these are often not operating in separation, but in fact can be quite
synchronous, often having approximately equal effects on living marine resource populations. I
review multivariate methods for exploring the relative prominence of any one of the triad of drivers,
and present empirical examples that clearly demonstrate partitioning variance among drivers is
necessary to fully understand living marine resource dynamics. Once such integrative measures have
been employed, how would one then disentangle them for practical, operational use when considering
these living marine resources? A proposal with several worked examples is provided to demonstrate
the absolute technical feasibility of doing so, particularly walking through a set of evaluation criteria
to determine when each of the main triad drivers might be prominent enough to consider in specific
living marine resource cases. I conclude by noting we need to stop wasting time arguing over whether
one driver may be more prominent over another, and instead explore those situations when each might
be important and if so how to estimate impacts therefrom.
The “Butterfish Smackdown”: Steps Toward the Development of an Operational Seascape
Ecology in Support of Ecosystem Management. John Manderson1, Josh Kohut2, Greg DiDomenico3,
and John Hoey4, 1Northeast Fisheries Science Center - Behavioral Ecology, USA; 2Rutgers University,
USA; 3Garden State Seafood Association; 4Northeast Fisheries Science Center - Cooperative
Research, USA; john.manderson@noaa.gov
Ecosystem management in the sea is holistic; based upon interdisciplinary science that considers the
physical, chemical and biological processes, including feedbacks with human ecological systems, that
structure and regulate marine ecosystems. Fisheries assessments in which ecosystem approaches are
applied are by their very nature more complex and subject to a greater uncertainty than single species
approaches although sound ecological science and considerations of key ecosystem processes should
reduce uncertainty. We argue that engaging stakeholders who are ecosystem experts as well as
ecosystem resource users into the science should makes for a better science that reflects the realities of
the ocean as well as a less acrimonious atmosphere in which to implement management and
regulation. We are testing this hypothesis in an ongoing collaborative project that has engaged experts
from the fishing industry as well as government and academic researchers in a collaborative field and
modeling effort to examine the effects of changing climate on seasonal habitat dynamics and
migration in butterfish and to use that research to address uncertainties in population assessments.
15
Environmental Monitors on Lobster Traps: Fishermen Contributing to our Ocean Observing
Systems. James Manning, Northeast Fisheries Science Center, NOAA Fisheries Service, 166 Water
Street, Woods Hole, MA, 02543, USA; james.manning@noaa.gov
Dozens of New England lobstermen have been recording hourly bottom temperatures on their traps
since 2001. The web-served data from approximately 60 fixed locations and depths around the Gulf of
Maine and Southern New England Shelf document processes at a variety time scales ranging from
semi-diurnal to inter-annual. Given the low cost of the instrumentation and the voluntary cooperation
of the participants, it should be possible to maintain the program and investigate multi-year climatic
scale cycles in the future. Since several of the participants have been submitting their haul data along
with their temperature records, we can begin to address the biophysical relationships. The effects of
storms, for example, on the catchability can be examined. Are the lobsters more apt to enter the trap at
a particular temperature or a particular change in temperature? While variables other than temperature
such as salinity, sea-level height, and current have also been measured, the most recent addition to the
suite of sensors is a digital camera to document biological activity in the trap. More camera
experiments are planned for the summer of 2012. While most of the data is not real-time, the long term
objective of this cooperative research project is to contribute to our nation's ocean observing systems.
Plans are underway to expand the operation both north and south of the Gulf of Maine region. Several
examples of processes occurring at different time scales will be described including wind-induced
turnovers, lunar cycles, and the longer term trend. The question of just how warm bottom water is this
year compared to the last 11 years, for example, can be addressed. Efforts to use this data to help
validate numerical models will also be discussed.
Building Strong Inference to Distinguish Fishing and Environmental Effects in a Data-limited
Fishery. Richard S. McBride1, Angela B. Collins2, Seifu Seyoum2, and Michael Tringali2, 1NOAA
Fisheries, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA, 02543, USA;
2
Florida Fish & Wildlife Conservation Commission, Fish & Wildlife Research Institute, 100 8th
Avenue SE, St. Petersburg, FL, 33701, USA; richard.mcbride@noaa.gov
We make inferences about the status of hogfish (Lachnolaimus maximus; Labridae) in Florida, based
on accumulated data about the fishery, life history, feeding, and stock structure. Hogfish are
protogynous hermaphrodites that constitute a modest fishery in Florida, and are landed primarily by
spear fishing. Data are limited for this species, relative to the more data-rich groupers and snapper
fisheries of the region, and the fishery itself was unregulated until 1994. When a minimum size limit
of 12 inches (305 mm) fork length was instituted, in response to data regarding the minimum size of
males, landings declined. This confirmed postulations that landings comprised a large number of small
fish. A subsequent survey of hogfish in the Florida Keys found size and age truncation within that
region; the effect was most severe in subregions closest to human development. Later, a survey of
hogfish across the west Florida shelf also found size and age truncation in nearshore strata. The results
of both surveys suggest that fishing pressure contributes to reduced yield in the most accessible areas.
Decreased reproductive potential by fishing is also evident, including reduced size at sex change and
reduced fecundity. An extreme red tide (the worst in 30 years) occurred during the second survey,
causing direct mortalities and/or emigration by hogfish, and decimating the prey base in nearshore
waters of the affected areas. In sum, fishing is a chronic source of high mortality causing size and age
truncation in some regions of Florida; however, some fast-growing fish do escape to offshore, deeper
waters, so fishing-induced changes to the growth genotype is unlikely at current levels of exploitation.
Red tide may also induce episodic mortality and future surveys should be designed to measure these
effects. There was no association between multilocus microsatellite genotypes and specimens’ sizes,
ages, or collection depths along the west Florida shelf; however, we detected robust signals of
16
occasional long-distance single-generation dispersal amidst strong regional differences in specimens
from the South Atlantic Bight, Florida Keys, and west Florida shelf.
When, Where, and Sometimes Why: Environmental Effects on Longfin Inshore Squid
Distribution and Implications for Fisheries Management. Owen C. Nichols, School for Marine
Science and Technology, University of Massachusetts – Dartmouth, 200 Mill Road – Suite 325,
Fairhaven, MA, 02719, USA; onichols@umassd.edu
Environmentally-driven spatiotemporal heterogeneity in the distribution of commercially exploited
marine species has direct implications for stock assessment and ecosystem-based fishery management
(EBFM). Identifying and quantifying important relationships between environmental variability and
the distribution of species, defining the spatiotemporal scales at which such relationships exist, and
determining the best methods to measure the related variables are necessary to develop EBFM
strategies and incorporate fishery and survey data into existing stock assessments. The longfin inshore
squid (Loligo pealeii) is distributed in continental shelf and slope waters of the northwest Atlantic
Ocean from Newfoundland to the Gulf of Venezuela and considered a single unit stock within its
range of commercial exploitation from Cape Hatteras north to Georges Bank. Survey-derived biomass
indices and fisheries landings vary at multiple spatiotemporal scales, particularly in inshore seasonal
spawning areas. Environmentally-driven intra-annual variability in L. pealeii distribution may affect
availability to annual trawl surveys, contributing to observed inter-annual variability in survey-derived
biomass indices used in stock assessment. Existing knowledge of loliginid squid distributional
ecology suggest the need for multi-scale studies of environmental effects on L. pealeii distribution in
order to adjust survey-derived biomass indices and develop EBFM strategies.
Impacts of Ghost Fishing from American Lobster Traps. Derek Perry1, Kelly Whitmore2, and
Robert Glenn1, 1Massachusetts Division of Marine Fisheries, Invertebrate Fisheries Program, 1213
Purchase Street, New Bedford, MA, 02744, USA; 2Massachusetts Division of Marine Fisheries,
Invertebrate Fisheries Program, 30 Emerson Ave., Gloucester, MA, 01930, USA;
Derek.Perry@state.ma.us
Over 4 million lobster traps are fished in the American lobster fishery, with around 400,000 traps set
in Massachusetts’ waters. Despite the large scale and high value of this fishery, little information
exists on the amount of lobster traps annually lost or how long these “ghost traps” continue to fish.
Legally required degradable escape panels are believed to reduce capture and mortality of lobsters, but
substantial loss of yield to the lobster fishery may occur even if ghost traps continue to fish short-term.
“Missing catch” may also undermine our ability to model lobster population dynamics. In May 2010,
we set and “abandoned” two baited six-pot trawls near Manomet Point, Cape Cod Bay and Penikese
Island, Buzzards Bay. Additional trawls were set at each location in November of 2010 and May of
2011. Divers surveyed the gear twice a month and recorded trap condition, species catch composition,
biological information from lobsters and mortality for trapped animals. Animals remained in the trap
to mimic “re-baiting.” Traps set in Cape Cod Bay actively fished for an average of 277 days after set
and were all disabled after 502 days. After over 700 days, 94% of the gear set in Buzzards Bay in
2010 is still fishing. Mortality rates for lobsters were between 0.011 and 0.017 per trap, per day based
on location and vent shape.
17
Are Shifts in Marine Species' Ranges Predictable? Insights from Both Coasts of North America.
Malin L. Pinsky1, Michael Fogarty2, Boris Worm3, Jorge L. Sarmiento4, and Simon A. Levin1, 1
Department of Ecology and Evolutionary Biology, 106A Guyot Hall, Princeton University, Princeton,
NJ, 08544, USA; 2 Northeast Fisheries Science Center, 166 Water St., Woods Hole, MA, 02543, USA;
3
Biology Department, Dalhousie University, Halifax, NS, B3H 4R2, Canada; 4 Atmospheric and
Ocean Sciences, 300 Forrestal Road, Princeton University, Princeton, NJ, 08544, USA;
pinsky@princeton.edu
Some of the more dramatic impacts of climate change are predicted to be geographic shifts in species
distributions as they track environmental conditions. These shifts are expected to have substantial
effects on fish population dynamics, but key questions remain about the processes affecting these
shifts, the factors driving differences among species, and the predictability of these shifts through time.
Our research uses three (Pacific) to four (Atlantic) decades of research bottom trawl surveys on the
continental shelves of North America to test whether the direction and magnitude of range shifts
among demersal fishes and invertebrates are predictable from local climate and species traits. We find
that range shifts vary substantially among species, but that local differences in climate trajectories can
explain otherwise surprising differences in direction of shift. Life history traits explain additional
variation among species. Results suggest which types of species will be winners and losers under
climate change and how fisheries are likely to be altered by shifting ranges.
Re-evaluation of the Threshold to Allow a Fishery in Light of Changes in Recruitment and
Survival Due to Whales, Disease, and the Environment. Terrance J. Quinn II1, Suzanne F.
Teerlink1, and Steven D. Moffitt2, 1Juneau Center, School of Fisheries and Aquatic Sciences,
University of Alaska Fairbanks, Juneau, AK, USA; 2 Alaska Department of Fish and Game, Cordova,
AK, USA; terry.quinn@alaska.edu
In the 1980s, the Pacific herring population in Prince William Sound supported a robust fishery under
a threshold management policy. The Exxon Valdez Oil Spill occurred in 1989 just prior to the fishery,
but the fishery was closed due to contamination threats. The fishery resumed in 1990-1992 but the
population collapsed just prior to the 1993 fishery. The fishery has been closed since 1993 (except for
a small fishery in 1997-1998), and the population has shown no signs of recovery. There are several
factors that have been proposed to explain the crash and the lack of recovery, but we hypothesize that
low recruitment (related to unknown environmental factors), high disease prevalence, and increased
predation by humpback whales are the most important. We have created an age-structured population
model that synthesizes stock assessment data, disease prevalence data, and a time series of humpback
whale abundance. Some researchers have queried whether the threshold management strategy, in
particular the threshold level below which fishing ceases, should be reexamined in light of the change
in population dynamics. We used our model to investigate this question. We looked at what the
unfished (pristine) population level would be under different recruitment, disease prevalence, and
humpback whale abundance scenarios. We then calculated the threshold level at 10% and 20% of
herring biomass. Not surprisingly, the threshold level varied substantially depending on which
scenario one selects to occur in the future.
18
The Northwest Atlantic Large-Fish Transition of the 1980s and the Identifiability Problem.
Brian Rothschild and Y. Jiao, School for Marine Science and Technology, University of Massachusetts
– Dartmouth, 706 South Rodney French Boulevard, New Bedford, MA, 02744, USA;
brothschild@umassd.edu
The composition of the “large-fish ecosystem” of the Northwest Atlantic Ocean changed markedly
during the past 50 years. This major ecological signal appears to be concentrated in the decade of the
1980s. At that time, rapid declines in thorny skate, ocean pout, cusk, witch flounder, and monkfish
were coupled with rapid increases in herring, haddock, northern shrimp, and spiny dogfish. Attempts
to understand this transition are stymied by the identifiability problem of separating relatively simple
fishing causality from extremely complex ocean environment causality. However, advances can be
made by further characterization of the fish abundance signal. These include coupling between fishing
mortality and stock size, identifying volatile species, taking account of abrupt population transitions,
and isolation of statistical noise. The paper concludes with speculations on the relation between
fishing mortality and the 1980s transition.
Sea Scallop (Placopecten magellanicus) Predation on the Northeast U.S. Continental Shelf:
Trends in Groundfish Feeding Habits. Stacy Rowe and Brian E. Smith, NOAA/NMFS/NEFSC, Food
Web Dynamics Program, 166 Water Street, Woods Hole, MA, 02543, USA; stacy.rowe@noaa.gov
The Atlantic sea scallop, Placopecten magellanicus, is currently the most valuable fishery in the U.S.
Groundfishes are known to consume sea scallops based on diet studies for specific geographic areas
(e.g. Georges Bank) or specific feeding behaviors (e.g. eating discarded scallop viscera). Here, we
examined 30 years of food habits data across the northeast U.S. continental shelf for the top six sea
scallop feeders by percent frequency of prey occurrence: Atlantic cod (Gadus morhua), Atlantic
wolffish (Anarhichas lupus), haddock (Melanogrammus aeglefinus), longhorn sculpin
(Myoxocephalus octodecemspinosus), ocean pout (Zoarces americanus), and spiny dogfish (Squalus
acanthias). The main objectives were to describe scallop predation by groundfishes and examine
spatial and decadal feeding trends on the northeast U.S. continental shelf. Sea scallops are consumed
either as whole individuals or viscera and this behavior appears to be predator specific. Scallop
feeding primarily occurred within the Mid-Atlantic Bight and Georges Bank regions of the shelf where
U.S. commercial scalloping is important. Additionally, indices of sea scallops in the diet (percent by
mass and percent frequency of occurrence) increased over the three decades sampled, at the same time
scallop population indices (kg tow-1) increased. Although sea scallop frequency of occurrence in
stomachs (1-2%) and diet composition by mass (1-4%) were generally low for many of these
groundfishes, approximately 15% of Atlantic wolfish stomachs on Georges Bank and 50% of the diet
by mass contained whole sea scallops. Thus, further investigation regarding the combined removal of
sea scallops by these groundfishes is warranted given the dietary implications reported here.
19
Effects of Climate Change on Fisheries Yields of Large Marine Ecosystems. Kenneth Sherman,
NMFS-NOAA Narragansett Laboratory, Narragansett, RI, USA; kenneth.sherman@noaa.gov
The world's 64 large marine ecosystems (LMEs) produce 80 percent of the annual global marine
fisheries landings. During recent decades, sea surface temperatures in 61 of the 64 LMEs have been
increasing. In relation to the surface warming trends, fisheries yields in subpolar LMEs of the
northeast Atlantic have been increasing. In contrast, fisheries biomass yields have been declining in
the more southerly LMEs of the northeast North Atlantic. The declining trend is correlated to a
reduction in plankton production in the Celtic-Biscay Shelf, North Sea, and Iberian Coastal LMEs.
Whereas the increasing trends in fisheries biomass yields in the Norwegian Sea, Iceland Shelf, and
Faroe Plateau LMEs are related to increases in zooplankton production followed by increased landings
of zooplanktivorous herring, capelin, and blue
whiting. These changes in fisheries biomass yields are examined in relation to potential effects of
climate model scenarios linking projected declines in primary productivity of the world oceans to
expected declines in fisheries yields of 14 LMEs within a circumglobal belt of warming waters located
between 20 degrees N latitude and 20 degrees S latitude.
Theories on the Influence of Environment on Atlantic Sea Scallop Distribution, Abundance and
Recruitment. Kevin D. E. Stokesbury and Bradley P. Harris, School for Marine Science and
Technology, University of Massachusetts – Dartmouth, 200 Mill Road – Suite 325, Fairhaven, MA,
02719, USA; kstokesbury@umassd.edu
The conundrum of large broods being independent of large numbers of spawning adults has
challenged fisheries scientists for years. Large recruitment pulses in marine populations are common
and conducive to significant changes in abundance. The sea scallop (Placopecten magellanicus)
fishery of New England has grown from a low of 5,500 metric tons landed in 1998 to an average of
26,000 metric tons from 2003 to 2010, with high prices worth $455 million US in 2010. Here we
examine this population growth using Sinclair’s member/vagrant hypothesis as a conceptual guide.
The environmental conditions supporting persistent adult populations over the previous 10 years are
examined. Sea scallop recruitment abundance and distribution, particularly the magnitude of large
recruitment events that are statistically different from average years, are measured and their influence
on the overall population growth is determined. Marine populations may not grow at a constant rate. It
may be that instantaneous rates or weighted averages of recruitment in population models may
inaccurately describe population dynamics driven by these large recruitment events.
20
Effect of a Changing Thermal Regime on Settlement Dynamics of Postlarval
American Lobster, Homarus americanus, in Southern New England. Kelly A. Whitmore1 and
Robert P. Glenn2, Massachusetts Division of Marine Fisheries,130 Emerson Ave, Gloucester, MA,
01930, USA; 21213 Purchase Street, New Bedford, MA, 02740, USA; Kelly.Whitmore@state.ma.us
The lobster stock in the Massachusetts portion of the Southern New England/Lobster Management
Area 2 is in poor condition. Stock abundance as measured empirically by the MA Marine Fisheries
bottom trawl survey is at all time low levels since the inception of the survey (1981). Commercial
catch from 2003 to 2007 accounted for five out of the six lowest values on record. Reductions in
postlarval settlement have also been observed, even during periods when spawning stock biomass was
at or near time series highs. This suggests that environmental parameters may be affecting hatching,
larval development and survivorship, or larval transport. Since the late 1990's, the inshore LMA 2
region has experienced a period of excessively warm summer water temperatures. This pattern has
persisted for longer than any other warming trend in the region, since 1945. Since water temperature
plays a vital role in many aspects of lobster life history including egg development, egg hatching, and
larval development, any alteration of these processes could produce variability in the timing and
geographic distribution of postlarval settlement. In 2009, we investigated possible mechanisms
influencing declines in young-of-the-year survey indices by monitoring the settlement process from
egg-hatch to postlarval settlement. Our objectives were to: determine the current geographic
distribution of lobster settlement in LMA 2, assess how well young-of-the-year settlement surveys
monitor year class strength, assess habitat suitability in nearshore waters of LMA 2 for settlement, and
examine the relationship between location of egg-bearing females and larval settlement, with the goal
of determining if declines in settlement are related to changes in environmental conditions. A suite of
satellite-tracked drifters, postlarval settlement collectors, and air-lift sampling efforts were used to
capture information on lobster larval dispersal and young-of-the-year settlement in the Rhode Island
and Massachusetts portions of LMA 2. Drifter-generated tracks identified coastal current patterns and
linked hatching areas to potential inshore recruitment regions. Settlement collector results confirmed
low settlement throughout the region. Temperature data were coupled with settlement patterns and
compared to historical regional temperature records. Results of this study elucidate environmental
factors likely influencing the decline and lack of recovery of the LMA 2 lobster fishery.
21
Incorporating Environmental Effects in Stock Assessments: Methods, Limitations, and Future
Directions. Michael J. Wilberg, Chesapeake Biological Laboratory, University of Maryland Center
for Environmental Science, USA; wilberg@cbl.umces.edu
Single species stock assessment models are widely used to provide fisheries management advice
around the world. However, some have argued that fisheries management has been less successful
than desired because of a focus on single species management and have called for more inclusion of
the environment in fisheries assessment and management. In this paper, I will review ways in which
single species stock assessments commonly incorporate environmental effects, limitations of these
approaches, and directions for future development. Assessment models often allow for effects of the
environment on the target species, although implicitly. The use of process errors in assessment models
allows for changes in the ecosystem to affect the population, but they often do not specify causes of
changes. Process errors are most commonly used to allow stochastic recruitment variability, but other
processes, such as catchability, growth, and natural mortality, have also been modeled in this manner.
Use of process errors may often be preferable to specifying the cause of changes because models with
specific mechanisms for changes can perform poorly if the modeled mechanism is incorrect.
Additionally, forecasts with mechanistic descriptions of processes rely on the ability to forecast the
driving factor. However, process error models create problems for development of reference points
and forecasting as well, particularly if trends are occurring in the underlying processes. For processes
with relatively slow changes in may be preferable to assume that the most recent conditions will
persist into the near future.
Evaluating Environmental Influence and Maturity on Growth and Subsequent Recruitment
Dynamics in Georges Bank Haddock (Melanogrammus aeglefinus). Mark Wuenschel1, Sandra
Sutherland1, Richard McBride1, Elizabeth Brooks and Kevin Friedland2, 1National Marine Fisheries
Service, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA, 02543-1026, USA;
2
National Marine Fisheries Service Northeast Fisheries Science Center, Narragansett Laboratory, 28
Tarzwell Drive, Narragansett, RI, 02882-1152, USA; mark.wuenschel@noaa.gov
Recent analyses indicate that there may be an environmental determinant of haddock recruitment
dynamics; specifically, the magnitude of the autumn bloom on Georges Bank (GB) is positively
correlated with recruitment of age 1 fish in the GB haddock stock the following year. Individual fish
allocate surplus energy derived from food into growth and reproduction. Immature fish are able to
direct all surplus energy into growth, whereas mature fish distribute surplus energy into both growth
and reproduction. Consequently for haddock, during ‘bloom booms,’ one might expect to observe
above-average reproduction in mature fish and above-average growth in immature fish, while in
‘bloom busts,’ the opposite would be expected (i.e., below average reproduction of mature fish and
below average growth of immature fish). We measured the annual increments in 2,297 otoliths of GB
haddock, age 1-12, collected during 1997-2011. Using increment width as a proxy for annual growth,
we explored associations between the environment (fall bloom) and growth across age, sex, and
maturity. This 15-year period provided contrast in the magnitude of both recruitment and spawner
abundance, as well as fall productivity (chlorophyll a magnitude). The otolith-derived growth histories
indicate that demographic components of the haddock stock respond differently. Somatic growth in
younger and immature fish is positively related to the magnitude of the autumn bloom, providing
insights into energy allocation and recruitment dynamics.
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