Spatial modeling of Bering Sea walleye pollock with integrated age-structured assessment models in a changing environment

2013 ◽  
Vol 70 (9) ◽  
pp. 1402-1416 ◽  
Author(s):  
Peter-John F. Hulson ◽  
Terrance J. Quinn ◽  
Dana H. Hanselman ◽  
James N. Ianelli
Keyword(s):  
Climate Change ◽  
Bering Sea ◽  
Walleye Pollock ◽  
Spatially Explicit ◽  
Parameter Estimates ◽  
Effective Sample Size ◽  
Climate Change Effects ◽  
Spatially Explicit Models ◽  
Distribution Shifts ◽  
Age Structured

Climate change may affect the spatial distribution of fish populations in ways that would affect the accuracy of spatially aggregated age-structured assessment models. To evaluate such scenarios, spatially aggregated models were compared with spatially explicit models using simulations. These scenarios were based on hypothetical climate-driven distribution shifts and reductions in mean recruitment of walleye pollock (Gadus chalcogrammus) in the eastern Bering Sea. Results indicate that biomass estimates were reasonably accurate for both types of estimation models and precision improved with the inclusion of tagging data. Bias in some aggregated model scenarios could be attributed to unaccounted-for process errors in annual fishing mortality rates and was reduced when estimating effective sample size or time-varying selectivity. Spatially explicit models that allow estimation of variability in movement and ontogenetic parameters (specified as a random walk process) were shown to be feasible, whereas models that misspecified ontogenetic movement and climate change effects resulted in biased biomass and movement parameter estimates. These results illustrate that more complex models may characterize processes better but may be less robust for management advice.

scholarly journals Climate change effects on Antarctic benthos: a spatially explicit model approach

2017 ◽  
Vol 141 (4) ◽  
pp. 733-746 ◽  
Author(s):  
Luciana Torre ◽  
Paulo C. Carmona Tabares ◽  
Fernando Momo ◽  
João F. C. A. Meyer ◽  
Ricardo Sahade
Keyword(s):  
Climate Change ◽  
Spatially Explicit ◽  
Explicit Model ◽  
Spatially Explicit Model ◽  
Climate Change Effects ◽  
Antarctic Benthos ◽  
Model Approach

scholarly journals Multi-model ensemble projections of climate change effects on global marine biodiversity

2014 ◽  
Vol 72 (3) ◽  
pp. 741-752 ◽  
Author(s):  
Miranda C. Jones ◽  
William W. L. Cheung
Keyword(s):  
Climate Change ◽  
Global Scale ◽  
The Arctic ◽  
Marine Biodiversity ◽  
Change Scenario ◽  
Global Changes ◽  
Distribution Models ◽  
Climate Change Effects ◽  
Distribution Shifts ◽  
Species Specific

Abstract Species distribution models (SDMs) are important tools to explore the effects of future global changes in biodiversity. Previous studies show that variability is introduced into projected distributions through alternative datasets and modelling procedures. However, a multi-model approach to assess biogeographic shifts at the global scale is still rarely applied, particularly in the marine environment. Here, we apply three commonly used SDMs (AquaMaps, Maxent, and the Dynamic Bioclimate Envelope Model) to assess the global patterns of change in species richness, invasion, and extinction intensity in the world oceans. We make species-specific projections of distribution shift using each SDM, subsequently aggregating them to calculate indices of change across a set of 802 species of exploited marine fish and invertebrates. Results indicate an average poleward latitudinal shift across species and SDMs at a rate of 15.5 and 25.6 km decade−1 for a low and high emissions climate change scenario, respectively. Predicted distribution shifts resulted in hotspots of local invasion intensity in high latitude regions, while local extinctions were concentrated near the equator. Specifically, between 10°N and 10°S, we predicted that, on average, 6.5 species would become locally extinct per 0.5° latitude under the climate change emissions scenario Representative Concentration Pathway 8.5. Average invasions were predicted to be 2.0 species per 0.5° latitude in the Arctic Ocean and 1.5 species per 0.5° latitude in the Southern Ocean. These averaged global hotspots of invasion and local extinction intensity are robust to the different SDM used and coincide with high levels of agreement.

scholarly journals Evaluating management strategies for eastern Bering Sea walleye pollock (Theragra chalcogramma) in a changing environment

2011 ◽  
Vol 68 (6) ◽  
pp. 1297-1304 ◽  
Author(s):  
James N. Ianelli ◽  
Anne B. Hollowed ◽  
Alan C. Haynie ◽  
Franz J. Mueter ◽  
Nicholas A. Bond
Keyword(s):  
Climate Change ◽  
Bering Sea ◽  
Management Strategies ◽  
Walleye Pollock ◽  
Status Quo ◽  
Theragra Chalcogramma ◽  
Recruitment Pattern ◽  
Control Rules ◽  
Eastern Bering Sea ◽  
Walleye Pollock Theragra Chalcogramma

Abstract Ianelli, J. N., Hollowed, A. B., Haynie, A. C., Mueter, F. J., and Bond, N. A. 2011. Evaluating management strategies for eastern Bering Sea walleye pollock (Theragra chalcogramma) in a changing environment. – ICES Journal of Marine Science, 68: 1297–1304. The impacts of climate change on fish and fisheries is expected to increase the demand for more accurate stock projections and harvest strategies that are robust to shifting production regimes. To address these concerns, we evaluate the performance of fishery management control rules for eastern Bering Sea walleye pollock stock under climate change. We compared the status quo policy with six alternative management strategies under two types of recruitment pattern simulations: one that follows temperature-induced trends and the other that follows a stationary recruitment pattern similar to historical observations. A subset of 82 Intergovernmental Panel on Climate Change climate models provided temperature inputs from which an additional 100 stochastic simulated recruitments were generated to obtain the same overall recruitment variability as observed for the stationary recruitment simulations. Results indicate that status quo management with static reference points and current ecosystem considerations will result in much lower average catches and an increased likelihood of fishery closures, should reduced recruitment because of warming conditions hold. Alternative reference point calculations and control rules have similar performance under stationary recruitment relative to status quo, but may offer significant gains under the changing environmental conditions.

scholarly journals Expected declines in recruitment of walleye pollock (Theragra chalcogramma) in the eastern Bering Sea under future climate change

2011 ◽  
Vol 68 (6) ◽  
pp. 1284-1296 ◽  
Author(s):  
Franz J. Mueter ◽  
Nicholas A. Bond ◽  
James N. Ianelli ◽  
Anne B. Hollowed
Keyword(s):  
Climate Change ◽  
Bering Sea ◽  
Late Summer ◽  
Walleye Pollock ◽  
Future Climate ◽  
Future Climate Change ◽  
Theragra Chalcogramma ◽  
Climate Projections ◽  
Eastern Bering Sea ◽  
Walleye Pollock Theragra Chalcogramma

Abstract Mueter, F. J., Bond, N. A., Ianelli, J. N., and Hollowed, A. B. 2011. Expected declines in recruitment of walleye pollock (Theragra chalcogramma) in the eastern Bering Sea under future climate change. – ICES Journal of Marine Science, 68: 1284–1296. A statistical model is developed to link recruitment of eastern Bering Sea walleye pollock (Theragra chalcogramma) to variability in late summer sea surface temperatures and to the biomass of major predators. The model is based on recent advances in the understanding of pollock recruitment, which suggest that warm spring conditions enhance the survival of early larvae, but high temperatures in late summer and autumn are associated with poor feeding conditions for young-of-year pollock and reduced recruitment in the following year. A statistical downscaling approach is used to generate an ensemble of late summer temperature forecasts through 2050, based on a range of IPCC climate projections. These forecasts are used to simulate future recruitment within an age-structured stock projection model that accounts for density-dependent effects (stock–recruitment relationship), the estimated effects of temperature and predation, and associated uncertainties. On average, recruitment in 2040–2050 should expectedly decline by 32–58% relative to a random recruitment scenario, depending on assumptions about the temperature relationship, the magnitude of density-dependence, and future changes in predator biomass. The approach illustrated here can be used to evaluate the performance of different management strategies and provide long-term strategic advice to managers confronted with a rapidly changing climate.

Climatic and economic drivers of the Bering Sea walleye pollock (Theragra chalcogramma) fishery: implications for the future

2013 ◽  
Vol 70 (6) ◽  
pp. 841-853 ◽  
Author(s):  
Alan C. Haynie ◽  
Lisa Pfeiffer
Keyword(s):  
Climate Change ◽  
Bering Sea ◽  
Climate Models ◽  
Walleye Pollock ◽  
Spatial And Temporal Variation ◽  
Theragra Chalcogramma ◽  
Climate Change Scenarios ◽  
Walleye Pollock Theragra Chalcogramma ◽  
The Impact ◽  
The Bering Sea

This paper illustrates how climate, management, and economic drivers of a fishery interact to affect fishing. Retrospective data from the Bering Sea walleye pollock (Theragra chalcogramma) catcher–processer fishery were used to model the impact of climate on spatial and temporal variation in catch and fishing locations and make inferences about harvester behavior in a warmer climate. Models based on Intergovernmental Panel on Climate Change scenarios predict a 40% decrease in sea ice by 2050, resulting in warmer Bering Sea temperatures. We find that differences in the value of catch result in disparate behavior between winter and summer seasons. In winter, warm temperatures and high abundances drive intensive effort early in the season to harvest earlier-maturing roe. In summer, warmer ocean temperatures were associated with lower catch rates and approximately 4% less fishing in the northern fishing grounds, contrary to expectations derived from climate-envelope-type models that suggest fisheries will follow fish poleward. Production-related spatial price differences affected the effort distribution by a similar magnitude. However, warm, low-abundance years have not been historically observed, increasing uncertainty about future fishing conditions. Overall, annual variation in ocean temperatures and economic factors has thus far been more significant than long-term climate change-related shifts in the fishery's distribution of effort.

Including mark–recapture data into a spatial age-structured model: walleye pollock (Theragra chalcogramma) in the eastern Bering Sea

2011 ◽  
Vol 68 (9) ◽  
pp. 1625-1634 ◽  
Author(s):  
Peter-John F. Hulson ◽  
Sara E. Miller ◽  
James N. Ianelli ◽  
Terrance J. Quinn
Keyword(s):  
Bering Sea ◽  
Walleye Pollock ◽  
Theragra Chalcogramma ◽  
Test Accuracy ◽  
Total Biomass ◽  
Eastern Bering Sea ◽  
Walleye Pollock Theragra Chalcogramma ◽  
Age Structured ◽  
Management Advice ◽  
Movement Parameters

Integrated assessment models used to evaluate fish stocks are becoming increasingly complex, with some capable of incorporating spatial considerations. Such a model has been developed to estimate movement of walleye pollock (Theragra chalcogramma) between the northwestern and southeastern eastern Bering Sea. In this study, we investigate the feasibility of estimating movement using spatially disaggregated data supplemented by tagging data. Monte Carlo simulation was used to test accuracy and variability of parameter estimation in model scenarios with and without tagging information. Total biomass estimates for models with and without tagging data were unbiased, but uncertainty was smaller when tagging data were available. Uncertainty was also reduced in regional biomass and movement parameters when including tagging data. Our findings indicate that tagging information would be important to provide reliable spatially explicit fisheries management advice for eastern Bering Sea pollock.

scholarly journals Nine decades of North Sea sole and plaice distribution

2011 ◽  
Vol 68 (6) ◽  
pp. 1090-1104 ◽  
Author(s):  
Georg H. Engelhard ◽  
John K. Pinnegar ◽  
Laurence T. Kell ◽  
Adriaan D. Rijnsdorp
Keyword(s):  
Climate Change ◽  
North Sea ◽  
Prey Availability ◽  
Habitat Modification ◽  
Climate Change Effects ◽  
The North ◽  
Research Survey ◽  
Short Time Span ◽  
Distribution Shifts ◽  
Short Time

Abstract Engelhard, G. H., Pinnegar, J. K., Kell, L. T., and Rijnsdorp, A. D. 2011. Nine decades of North Sea sole and plaice distribution. – ICES Journal of Marine Science, 68: 1090–1104. Recent studies based mainly on research survey data suggest that within the North Sea, sole Solea solea and plaice Pleuronectes platessa have exhibited distribution shifts in recent decades—on average southward for sole and northward to deeper waters for plaice. Various hypotheses may account for such shifts, including climate change effects and more intensive fishing in southern and shallower waters; but the relatively short time-span of datasets analysed so far (∼3 decades) has complicated the separation of these two effects. We have made use of a unique dataset of catch and effort data for British North Sea trawlers; these cover nine decades (spanning the period 1913–2007) and are spatially detailed by ICES rectangle (0.5° latitude by 1° longitude). We quantify, for the first time, long-term distribution changes of North Sea sole and plaice over a period approaching a century, and demonstrate that the distribution shift in plaice was attributable to climate change rather than to fishing, but that both climate and fishing played a role in the distribution shift of sole. The discussion also highlights the potential impact of additional factors, including eutrophication, prey availability, and habitat modification.

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