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NOAA’s Alaska Fisheries Science Center’s (AFSC) Ecosystems and Fisheries-Oceanography Coordinated Investigations (EcoFOCI) program has collected spring ichthyoplankton abundance data in the Gulf of Alaska since 1981. Collections were made nearly annually until 2011 when sampling was reduced to only odd years. This dataset is used to better understand population recruitment of major fish species in the GOA and provides early warning of potential year-class strength to inform fisheries management. However, gaps in the time series during even years have made it more difficult to interpret the interannual variability of ichthyoplankton abundance in such a dynamic ecosystem. Recent collaboration with the Northern Gulf of Alaska Long Term Ecological Research (NGA LTER) program has allowed for additional spring sampling of ichthyoplankton in the GOA annually since 2018. Larval fish data collected by the NGA LTER were combined with EcoFOCI data and used to estimate abundance in years when EcoFOCI had no field presence in the GOA. Five taxa were determined to be suitable for this approach based on their percent occurrence in both surveys. A generalized additive model (GAM) was fit to ichthyoplankton data from 1981 to 2022 collected by both EcoFOCI and NGA LTER and used to predict larval abundances in 2018, 2020, and 2022. For each species, models with two different error distributions were compared and shown to produce similar predictions of larval abundance. This report provides a model framework for predicting interannual larval fish abundance while controlling for differences in sampling methodologies, timing, and location, and identifies a subset of taxa for which this framework is currently appropriate. As additional years of concurrent sampling are added in future, this approach has the potential to improve our understanding of interannual variation in ichthyoplankton dynamics and provide more comprehensive indicators for ecosystem-based fisheries management. 

Abstract Warming temperatures elicit shifts in habitat use and geographic distributions of fishes, with uneven effects across life stages. Spawners and embryos often have narrower thermal tolerances than other life stages, and are thus particularly sensitive to warming. Here, we examine the spatiotemporal variability of thermal spawning habitat for Pacific cod in the eastern Bering Sea. Specifically, we use bottom temperatures from downscaled global climate models coupled with an experimentally-derived hatch success and temperature relationship to predict how the spatial extent, mean latitude, and consistency of thermal spawning habitat has varied over time. Predictions are validated with observations of spawning adults and early larvae. We find that habitat availability has not increased in the past but is predicted to increase and shift northward in the future, particularly if no climate change mitigation occurs. Habitat hotspots are consistent across shorter time periods but do shift across the shelf by the end of the century such that highly suitable areas in the past and present are not predicted to be suitable in the future. This work highlights the importance of coupling experimental data with climate models to identify the complex and mechanistic dynamics among temperature, life histories, and ecology, particularly under climate change. 

Societies increasingly use multisector ocean planning as a tool to mitigate conflicts over space in the sea, but such plans can be highly sensitive to species redistribution driven by climate change or other factors. A key uncertainty is whether planning ahead for future species redistributions imposes high opportunity costs and sharp trade-offs against current ocean plans. Here, we use more than 10,000 projections for marine animals around North America to test the impact of climate-driven species redistributions on the ability of ocean plans to meet their goals. We show that planning for redistributions can substantially reduce exposure to risks from climate change with little additional area set aside and with few trade-offs against current ocean plan effectiveness. Networks of management areas are a key strategy. While climate change will severely disrupt many human activities, we find a strong benefit to proactively planning for long-term ocean change.