2023 AMSS Abstract Book

Gulf of Alaska | Fishes and Fish Habitats

Investigating overwintering success of age-0 Pacific cod with pre-winter measures of body condition, diet, and lipid reserves Presenter: Alisa Abookire , alaskacor@gmail.com, Alaska Coastal Observations and Research

Louise Copeman , louise.copeman@noaa.gov, Alaska Fisheries Science Center Ben Laurel , ben.laurel@noaa.gov, NOAA Alaska Fisheries Science Center Mike Litzow , mike.litzow@noaa.gov, Alaska Fisheries Science Center, NOAA Fisheries

Current abundance estimates for age-0 Pacific cod ( Gadus macrocephalus ) in the Gulf of Alaska are based entirely on summer observational data. The overwintering survival of age-0 cod is one of several critical recruitment stages; yet, it is not well understood. Years of high age-0 abundance yield inconsistent numbers of age-1 recruits in the following spring, with some years having high numbers of age-1 cod (2000 year class) and other years having low numbers (2017 year class). Given that the variability in lipid storage occurs during the period from Aug-Dec when the body condition is not typically being measured, our goal was to provide some of the first pre-winter condition data that is most closely coupled to the overwintering survival bottleneck. Specifically, we measured the seasonal variation in body condition, diet, and lipid allocation of age-0 cod to determine if and when these measures can indicate future overwintering success. Sampling for age-0 Pacific cod occurred in eelgrass habitat located near Kodiak, Alaska, in monthly collections from May – December during three years (2018 – 2020). Laboratory analysis of age-0 cod condition, diet, and lipid reserves were measured for approximately 25 fish/month. Sufficient diet and lipid stores may allow juveniles to achieve higher success in surviving their first overwintering period. Evaluation of early warning indicators will contribute to developing new methods for monitoring and managing commercially important stocks under increased environmental variability.

Alaska Marine Science Symposium 2023 196

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