Synthesizing integrated ecosystem research to create informed stock-specific indicators for next generation stock assessments

Shotwell, S. Kalei; Pirtle, Jodi L.; Watson, Jordan T.; Deary, Alison L.; Doyle, Miriam J.; Barbeaux, Steven J.; Dorn, Martin W.; Gibson, Georgina A.; Goldstein, Esther D.; Hanselman, Dana H.; Hermann, Albert J.; Hulson, P.J.F.; Laurel, Benjamin J.; Moss, Jamal H.; Ormseth, Olav A.; Robinson, David L.; Rogers, Lauren A.; Rooper, Christopher N.; Spies, Ingrid; Strasburger, Wesley; Suryan, Robert M.; Vollenweider, Johanna J.

doi:10.1016/j.dsr2.2022.105070

Cited by 9 publications

(7 citation statements)

References 109 publications

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“…Despite missing mechanistic information, condition metrics for early life stages (e.g., lipids, size‐at‐age, total energy density) are used in fisheries management of Alaska gadids (Shotwell et al, 2022). The implicit understanding is that larger or faster growing members of a cohort have a survival advantage during the winter, because they are less vulnerable to predators (Hurst, 2007) and can carry more fall energy reserves through the winter period of low productivity (Byström et al, 2006; Post & Evans, 1989; Thompson et al, 1991).…”

Section: Discussionmentioning

confidence: 99%

“…Year class strength data for both larvae and juveniles were plotted with the annually updated NOAA‐AFSC Pacific cod spawning habitat index based on the observed temperatures for GOA at GAK1 (see Laurel & Rogers, 2020; Shotwell et al, 2022). Time series were inspected for autocorrelation prior to analyses and examined by way of Pearson's correlation coefficients.…”

Section: Methodsmentioning

confidence: 99%

“…with the annually updated NOAA-AFSC Pacific cod spawning habitat index based on the observed temperatures for GOA at GAK1 (seeLaurel & Rogers, 2020;Shotwell et al, 2022). Time series were inspected for autocorrelation prior to analyses and examined by way of Pearson's correlation coefficients.An annual marine heatwave index was developed from the daily sea surface temperatures record of the NOAA High-resolution Blended Analysis Data database (National Oceanic and Atmospheric Administration, 2017) and filtered to only include data from the central GOA between 145 and 160° W longitude for waters less than 300 m in depth.…”

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confidence: 99%

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Pacific cod in the Anthropocene: An early life history perspective under changing thermal habitats

Laurel

Abookire²,

Barbeaux

et al. 2023

Fish and Fisheries

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The rapid decline in Pacific cod (Gadus macrocephalus, Gadidae) biomass following multiple Gulf of Alaska marine heatwaves (2014–2016 and 2019) may be one of the most dramatic documented changes in a sustainably managed marine fishery. As such, fisheries managers are exploring new recruitment paradigms for Pacific cod under novel environmental conditions. In this review, we address the challenges of managing and forecasting Pacific cod populations in the Eastern Pacific where thermal habitats for early life stages are undergoing varying rates of change across space and time. We use observational data to examine changes in distribution, abundance and demographics of the population from 1993 to 2020, and model contemporary and future changes of thermal habitat for both spawning success and age‐0 juvenile growth potential. Results indicate that reduced spawning habitat and early life stage abundance may be a precursor to regional population decline, but the recent apparent increases in size‐at‐age of pre‐recruits will have unknown impacts on future recruitment in these regions. We contend that continued monitoring of early life stages will be necessary to track changes in phenology and growth that likely determine size‐at‐age and the survival trajectories of year classes into the adult population. These include complex size‐ and temperature‐dependent energetics spanning seasonal habitats through the first winter. Climate‐ready management of Pacific cod will, therefore, require new process investigations beyond single‐season surveys focused on one‐life stage.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Pacific cod in the Anthropocene: An early life history perspective under changing thermal habitats

Laurel

Abookire²,

Barbeaux

et al. 2023

Fish and Fisheries

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“…SDM predictions are used in management to describe important habitat for marine species (like EFH), project species habitat‐related distribution shifts under climate change scenarios (e.g. Rooper et al., 2021), to obtain indices of abundance and age composition from monitoring data (O'Leary et al., 2020), and to develop stock‐specific metrics and status indicators that can be used in stock assessments (Shotwell et al., 2022). The results of this study highlight the importance of keeping management goals in mind when selecting SDM methods and interpreting their results.…”

Section: Discussionmentioning

confidence: 99%

An ensemble approach to species distribution modelling reconciles systematic differences in estimates of habitat utilization and range area

Harris,

Pirtle,

Laman

et al. 2023

Journal of Applied Ecology

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Species distribution models (SDMs) are an important tool for conservation and resource management. However, managers are often interested in derived quantities such as range or area occupied, and how these are calculated can have a large impact. Ecosystem‐based management typically requires spatial information about species distributions, which is increasingly generated from SDMs that are then processed to identify occupied habitat. Many types of SDMs exist, but there is little research regarding how this model‐choice affects outcomes when defining occupied habitat, in part because these models generate different types of output. We fit a suite of five SDMs to data for 208 species/life stage combinations in three marine ecosystems while ensuring that they all estimate a ‘common currency’ of numerical abundance. We then calculate out‐of‐sample predictive performance to weight these constituents in an ensemble SDM. Results show that this approach can reduce bias arising from a priori specification of individual SDMs resulting in a better fit to survey data (constituent SDMs had a median of 7% higher RMSE). The SDMs had a range of responses relative to the ensemble, with MaxEnt typically predicting a median 1.3% higher area occupied, and negative‐binomial GAMs predicting 21.4% lower area occupied. Two potential methods of identifying the area of occupied habitat from SDM outputs are compared—probability‐based and cumulative density‐based methods. We find that cumulative densities result in smaller estimates of area occupied, and we recommend careful consideration of how model‐choice affects occupied‐habitat estimates in spatial management. Policy implications: Finally, we discuss how the patterns identified during the 5‐year Review of Essential Fish Habitat for Alaska should be carefully considered by managers using SDMs to identify habitat that may be impacted by anthropogenic activities.

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“…Spatially integrated stock assessments and other spatial management procedures, which often rely on temporally static species distributions (Link et al 2011, Punt et al 2013, would benefit from dynamic model hindcasts that help set the stage for changes in stock status. Population percentiles such as those estimated in this and other studies (Shotwell et al 2022) can be used to identify interannual variation in spatial structure, inform EFH consultations that reference the current state of the ecosystem and improve our understanding about the cumulative impacts of climate change. Multispecies extensions of our work would also serve as informative additions to reports that are designed to track community-level trends in ecosystem components (Siddon 2021).…”

Section: Applications For Fisheries Managementmentioning

confidence: 93%

Climate‐informed models benefit hindcasting but present challenges when forecasting species–habitat associations

et al. 2022

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Although species distribution models (SDMs) are commonly used to hindcast finescale population metrics, there remains a paucity of information about how well these models predict future responses to climate. Many conventional SDMs rely on spatiallyexplicit but time-invariant conditions to quantify species distributions and densities. We compared these status quo 'static' models with more climate-informed 'dynamic' SDMs to assess whether the addition of time-varying processes would improve hindcast performance and/or forecast skill. Here, we present two groundfish case studies from the Bering Sea -a high latitude system that has recently undergone considerable warming. We relied on conventional statistics (R 2 , % deviance explained, UBRE or GCV) to evaluate hindcast performance for presence-absence, numerical abundance and biomass of arrowtooth flounder Atheresthes stomias and walleye pollock Gadus chalcogrammus. We then used retrospective skill testing to evaluate near-term forecast skill. Retrospective skill testing enables direct comparisons between forecasts and observations through a process of fitting and forecasting nested submodels within a given time series. We found that the inclusion of time-varying covariates improved hindcasts. However, dynamic models either did not improve or decreased forecast skill relative to static SDMs. This is likely a result of rapidly changing temperatures within the ecosystem, which required models to predict species responses to environmental conditions that were outside the range of observed values. Until additional model development allows for fully dynamic predictions, static model forecasts (or persistence forecasts from dynamic models) may serve as reliable placeholders, especially when anomalous conditions are anticipated. Nonetheless, our findings demonstrate support for the use of retrospective skill testing rather than selecting forecast models a priori based on their ability to quantify species-habitat associations in the past.

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Synthesizing integrated ecosystem research to create informed stock-specific indicators for next generation stock assessments

Cited by 9 publications

References 109 publications

Pacific cod in the Anthropocene: An early life history perspective under changing thermal habitats

Pacific cod in the Anthropocene: An early life history perspective under changing thermal habitats

An ensemble approach to species distribution modelling reconciles systematic differences in estimates of habitat utilization and range area

Climate‐informed models benefit hindcasting but present challenges when forecasting species–habitat associations

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