October 16, 09:15 (W1-9753)
An ecosystem and optimisation framework for fish population dynamics assessment under
the influence of fishing and climate
Patrick Lehodey1, Inna Senina1, Anne-Cecile Dragon1, Anna Conchon1, Olivier Titaud1, John
Hampton2, Simon Nicol2, Teja Arief Wibawa1, Beatriz Calmettes1, John Sibert3, Hidetada
Kyiofuji4, Mélanie Abécassis5, Olga Hernandez1 and Philippe Gaspar1
1CLS,
Space Oceanography Division, Department of Marine Ecosystems, Ramonville St Agne,
France. E-mail: plehodey@cls.fr
2 Oceanic Fisheries Programme, Secretariat of the Pacific Community, Noumea, New Caledonia.
3 SOEST, University of Hawaii at Manoa, Honolulu, USA.
4 National Research Institute of Far Seas Fisheries (NRIFSF), Shimizu, Shizuoka, Japan.
5 Pacific Islands Fisheries Science Center, Ecosystems and Oceanography Division, Honolulu,
USA.
A modelling framework is presented to predict and analyze the spatial dynamics of marine
exploited and protected fish species with mechanisms constrained by relationships based on the
bio-physical environment predicted from coupled 3D models of ocean physics and
biogeochemistry. The development of an optimization approach based on Maximum likelihood
techniques and adjoint model provides a robust approach to estimate density distributions of
functional groups of zooplankton, pelagic micronekton and of all cohorts of the exploited agestructured fish population simulated, from larvae to oldest adults, using all available data
(acoustic, catch and effort, size frequencies, tagging data, eggs and larvae densities). The
simulation framework allows reconstructing past history of fish population, to dissociate
fishing impacts from natural variability, and to forecast population dynamics under climate
change based on IPCC scenarios of release of greenhouse gases. This spatial Eulerian ecosystem
and population dynamics model (SEAPODYM) is based on advection-diffusion equations
simulating random and oriented movements. Then spatio-temporal dynamics of species of
interest are simulated under the influence of environment and fishing pressure. Surface currents
passively transport larvae, while young and adult fish movements are driven using habitat
indices. A description of multiple fisheries with spatially disaggregated fishing data (effort,
catch size frequencies of catch) is included in the model. This model has been used to obtain
optimized parameterization and quantitative stock estimates for several tuna species (Pacific
skipjack, yellowfin, bigeye and swordfish, and south Pacific and North Atlantic albacore) over
past and present fishing periods. Projections under Climate Change scenarios were also
explored using forcing variables from Climate Models.
October 16, 09:50 (W1-9786)
The International Scientific Committee for Tuna and Tuna-like Species in the North
Pacific Ocean
The International Scientific Committee for Tuna and Tuna-like Species in the North Pacific
Ocean (ISC) was established in 1995 to provide scientific advice on the stocks and fisheries of
tuna and tuna-like species in the North Pacific Ocean to the Member governments and regional
fisheries management organizations. The two main goals of the ISC are (1) to enhance scientific
research and cooperation for conservation and rational utilization of the species of tuna and tunalike fishes that inhabit the North Pacific Ocean during a part or all of their life cycle; and (2) to
establish the scientific groundwork for the conservation and rational utilization of these species
in this region. Research is facilitated through the establishment of Working Groups that focus on
understanding the dynamics and ecology of highly migratory species (HMS) and associatedspecies populations, in order to accurately assess stock condition and status. The structure and
function of ISC will be presented, as well as current stock assessment modeling structures used
to assess HMS stock status and condition. While considerable uncertainty exists in all
assessments, uncertainty may be reduced through the incorporation of environmental data into
assessment models. Potential ways of integrating environmental data into the assessments and
possible benefits will be presented.
October 16, 10:15 (W1-9784)
Review of PICES/FUTURE and relation to ISC
Suam Kim
Dept. of Marine Biology, Pukyong National University
599-1 Daeyeon3-dong, Nam-gu, Busan, 608-737, Korea
E-mail: suamkim@pknu.ac.kr
Phone and Fax: +82-51-629-5923
PICES, the North Pacific Marine Science Organization, is an intergovernmental scientific
organization that promotes and coordinates marine research activities in the northern North
Pacific to achieve scientific knowledge about the ocean/climate environments, their ecosystems
including living resources, and the impacts of human activities. Joint efforts by international
organizations are recommended. This presentation reviews the structure of the PICES, and
summarizes the routine processes to form expert groups. Details on the functions, membership
and leadership of various Expert Groups (Sections, Working Groups, Advisory Panels, Study
Groups, etc.) will be introduced with some historic and existing examples within PICES. The
possibility of cooperative activity with ISC will be discussed, especially focusing on scientific
framework to assess the dynamics of pelagic fish under climate/environmental variability.
October 16, 11:00 (W1-9782)
A review of CLIOTOP and related research programs in the North Pacific
Francisco E. Werner
Southwest Fisheries Science Center
8901 La Jolla Shores Drive
NOAA/NMFS
La Jolla, CA 92037 USA
E-mail: cisco.werner@noaa.gov
Phone: +1-858-546-7081
FAX: +1- +1-858-546-5655
A review of the CLIOTOP (CLimate Impacts on Oceanic TOp Predators) and related programs
http://www.imber.info/index.php/Science/Regional-Programmes/CLIOTOP will be presented to
provide background of advances in the understanding of physical forcing on the structuring of
pelagic ecosystems, with particular attention to North Pacific systems. CLIOTOP, now part of
the IMBER Program, was established during GLOBEC with the aim of coordinating large-scale
worldwide comparative efforts aimed at elucidating the key processes involved in the impact of
both climate variability (at various scales) and fishing on the structure and function of open
ocean pelagic ecosystems and their top predator species. The discussion will include the present
state of predictive capabilities for the dynamics of top predator populations and oceanic
ecosystems that combines fisheries and climate (i.e. environmental) effects.
October 16, 11:25 (W1-9793)
Modeling the Pacific Ocean: present capabilities and challenges for the next decade in
relation to pelagic ecosystems
Enrique Curchitser
Department of Environmental Sciences
Rutgers University
14 College Farm Road
New Brunswick, NJ 08901 USA
Email: enrique@esm.rutgers.edu
A review of the advances and present capabilities of basin-scale modeling of the North Pacific
will be presented. Focus will be on the links between physical and ecosystem components, from
lower trophic levels (biogeochemistry, primary and secondary producers) through to the spatially
explicit inclusion of fish populations and fishing fleets. Selected examples will be presented on
50-year hindcasts of coastal pelagic species, as well as recently computed results of 100-year
forward projections of the California Current Ecosystem under selected climate change
scenarios. Finally, challenges for open-ocean/basin scale pelagic populations will be outlined
and expected advances during the next decade discussed.
October 16, 11:50 (W1-9762)
Oceanographic influences on albacore distribution in the Northeast Pacific: importance of open
ocean and coastal frontal zones
Steven L. H. Teo1, Yi Xu1, Karen Nieto1, Sam McClatchie1, and John Holmes2
1
Southwest Fisheries Science Center, NOAA/NMFS, La Jolla, CA, USA
2
Pacific Biological Station, Department of Fisheries and Oceans Canada, Nanaimo, BC, Canada
Albacore tuna (Thunnus alalunga) is a highly migratory species found primarily in subtropical
and temperate waters, and is the target for numerous, highly valuable fisheries. In the Northeast
Pacific, albacore are caught in both open ocean and coastal waters but oceanographic conditions
and influences on albacore distribution in these areas can be quite different. We examine the
spatial and temporal patterns in albacore catch-per-unit-effort (CPUE) in relation to
oceanographic conditions in the open ocean and coastal waters, especially the influence of fronts.
Frontal features, as indicated by SST gradients, were highly influential on albacore distribution
in both open ocean and coastal waters. In the open ocean, high albacore CPUE occurred in
regions with high SST gradients like the North Pacific Transition Zone (NPTZ). In the NPTZ,
albacore CPUE exhibited seasonal and interannual shifts in distribution that corresponded to
shifts in the areas with high SST gradients. In coastal waters, albacore CPUE was highly
influenced by SST and chlorophyll at fishing locations, albeit with substantial seasonal and
interannual variability. Albacore CPUE was higher near warm, low chlorophyll oceanic waters,
and near SST fronts. Model results appeared to be robust and model-predicted albacore CPUE
were similar to observations but the model was unable to predict very high CPUEs in some
areas. These results suggest that simple extrapolation of future SSTs under various climate
change scenarios may not be enough to predict how albacore distribution may change under
future climate change.
October 16, 14:00 (W1-9705)
ABSTRACT
We examined difference in the abundance and growth of larval Pacific anchovy estimated by
RNA/DNA ratio in the water masses coming from the Tsushima Warm Current (TWC) and
Changjiang Diluted Water (CDW), and the South Korean Water (SKCW) affecting oceanic
environment in the southern waters of Korea in June. The larval anchovy was only collected in
the water masses of the SKCW and CDW during the survey. No significant difference was
recognized in the abundance between the two water masses, implying that the intrusion of the
CDW to the coastal waters could be played a major role to increase abundance of tertiary
producers such as fish larvae in coastal pelagic ecosystem. The mean RNA/DNA ratios of the
larvae in the water mass of the CDW were higher than those in the water mass of the SKCW. A
quadratic relationship between the mean RNA/DNA ratios and the sea surface temperature (SST)
suggests that optimal growth temperature during the larval stages of Pacific anchovy in the
western North Pacific would be found at SST of 21-22℃.
October 16, 14:25 (W1-9472)
Projected responses of the central North Pacific pelagic ecosystem to climate-induced
changes in micronekton communities
C. Anela Choy, Phoebe Woodworth-Jefcoats and Jeffrey J. Polovina
NOAA, Pacific Islands Fisheries Science Center, Ecosystems and Oceanography Division,
Honolulu, HI, USA. E-mail: carolyn.choy@noaa.gov
Ecosystem models have been widely used to examine potential food web impacts due to climate
induced changes at the base of the marine food web, as well as top down changes induced by
fishing removals. Here, we address potential ecosystem changes resulting from direct climateinduced impacts to micronekton food web components (small fishes, crustaceans, and
cephalopods ~2-20cm that form the primary forage base for large pelagic fishes). We updated an
existing Ecopath with Ecosim (EwE) model for the area of the central North Pacific occupied by
the Hawaii-based pelagic longline fishery. Specifically, we focused on representation of the
lesser known non-target fish species (e.g., lancetfish, opah, snake mackerel) and mid-trophic
micronekton. The model comprises 41 functional groups, organized into approximately five
trophic levels where sharks and billfishes occupy the top of the pelagic food web. Detailed diet
data argue for specialized niche partitioning amongst large commercially harvested fish species,
suggesting that the central North Pacific pelagic ecosystem does not function according to
‘wasp-waist’ control, as has been previously described from other systems such as the California
Current and eastern Australia. The relative impacts between key forage groups and key
predators are also presented using EwE. Sensitivity analysis is used to project ecosystem
impacts from climate-induced changes to the following micronekton groups: epi-/meso/bathypelagic fishes, myctophids and gonostomatids epi-/mesopelagic molluscs, decapod
crustaceans, and gelatinous zooplankton. Model results can help advance the understanding of
overall ecosystem structure of different pelagic systems, particularly how biomass flows through
diverse mid-trophic forage groups.
October 16, 14:50 (W1-9467)
Prominent meanders of the Sub-Tropical Counter Current and pelagic fish catch
Daisuke Hasegawa1, Satoshi Mitarai2 and Koichi Hirate3
1
Tohoku National Fisheries Research Institute, Fisheries Research Agency, Miyagi, Japan
E-mail: daisukeh@affrc.go.jp
2
Okinawa Institute of Science And Technology Graduate University, Okinawa, Japan
3
Okinawa Prefectural Fisheries Research and Extension Center, Okinawa, Japan
In December 2012, pelagic fish catch off the south east of Ryukyu Islands was extremely low.
While we were trying to identify the reason of the poor catch, we found series of large lowpressure areas at the northern edge of the North Pacific Sub-Tropical Counter Current (STCC)
system. The STCC strengthened and turned along the low pressure edges and caused remarkable
meanders with meridional oscillations of O (1000 km) at the east of Ryukyu islands. The
satellite sea surface height and the ship-based observation showed the strengthened STCC jet of
the first meander, which reached 1 m/s at the surface associated with a quasi geostrophic density
structure. The meander transported tropical water to the north and replaced the subtropical
waters with warm and low salinity surface water and high salinity subsurface water. The AVISO
time series of the surface geostrophic velocity indicated that this event associated with a
meridional jet of O (1 m/s) extended from 20oN to 25oN was the first event ever happened in the
last 20 years. The meridionally averaged kinetic energy time series of the area indicated the
quick development of the strong meander around 138oE. The timings when the eddies
strengthened and merged coincidentally overlapped when some of typhoons stagnated and
passed above these cyclonic eddies. This fact suggests that the effect of the typhoon forcing
contributed causing this rare STCC meander event.
October 16, 15:30 (W1-9700)
Simulation study on the distribution of skipjack tuna in relation to Fish Aggregating
Devices (FADs) during ENSO
Eunjung Kim1,2 and John R. Sibert1
1
Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa,
Honolulu, HI, USA. E-mail: kimeunju@hawaii.edu
2
Pelagic Fisheries Research Program, Joint Institution for Marine & Atmospheric Research, University of Hawaii at
Manoa, Honolulu, HI, USA
Tunas and other pelagic fish are often found in association with floating object and remain near the
surface. Taking advantage of the behavior, fish aggregating devices (FADs, i.e. man-made floating
objects) are commonly using for tuna fisheries. Nearly half of the world tuna catch is made from schools
associated with FAD as a result of the prevalence in its use in purse seine fishery since early 1990s. Some
studies estimated 47,000-105,000 of FADs put into the oceans each year. Drifting FADs (dFADs) are
freely in ocean currents in the open ocean unlikely anchored FADs (aFADs) which are commonly found
in the coastal waters. The dFADs can carry away the associated tuna with them by the current. The
information on FADs is very limited because of the spatial and temporal variability. In this study, we
analyzed the distribution of FADs using purse seine sets, and we simulated the distribution of skipjack
tuna using the FAD advection-diffusion reaction model (FAD-ADRM) based on the distribution of FADs.
In particular, we compared the distribution of skipjack tuna in ENSO and normal condition, which may
show the impact of oceanographic change and human disturbance on skipjack tuna movement.
October 16, 15:55 (W1-9686)
The relationship between ecological characteristics of Pacific bluefin tuna (Thunnus
orientalis) fisheries and environmental factors around Jeju Island
Ari Shin1,2, Sang Chul Yoon2 and Suam Kim1
1
Department of Marine Biology, Pukyong National University, Busan, R Korea
E-mail: arishin8@gmail.com
2
National Fisheries Research and Development Institute, R Korea
Pacific bluefin tuna (Thunnus orientalis) is one of the important species in the North Pacific as well as in
Korea. Investigation on the important environmental factors for controlling the biology and fisheries of T.
orientalis was carried out using Korean fishery statistics and climate and oceanographic information.
Korean fishermen caught small pelagic fishes such as chub mackerel by offshore large purse seines, and
T. orientalis accidently were caught mostly by this fishery. The monthly catch of T. orientalis around Jeju
Island from 2004 to 2013 showed a negative correlation (r=-0.870, p<0.01) with the seawater temperature
at 50 m and had a significant positive correlation (r=0.856, p<0.01) with the Pacific Decadal Oscillation
(PDO) Index. The highest catch of T. orientalis around Jeju Island occurred in the seawater temperature
range of 16-17°C or near the frontal area where offshore and coastal water masses collide. The length of
T. orientalis ranged from 19 cm to 193 cm in folk length (FL). The mean length of T. orientalis in each
year had a negative correlation (r=-0.592, p<0.01) with the seawater temperature at 50 m and had a
significant positive correlation (r=0.688, p<0.05) with the PDO Index.