Size-at-age of Pacific cod in the Eastern Bering Sea, 1994-2016

• Main Author: Lorenzo Ciannelli
• Format: Dataset
• Language: unknown
• Published: Research Workspace 2018
• Subjects: OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN > BERING SEA; Gadus macrocephalus; Pacific cod, morue du Pacifique, bacalao del Pacifico; 1994-2016; summer; age methodology; Catch-Survey Analysis; bottom trawl; Groundfish survey; spatial dynamics; biosampling; otolith; growth; Marine Environment Monitoring; North Pacific Research Board; age frequency; length frequency; cohort effects; Bering Sea; Pacific; Alaska
• Online Access: https://search.dataone.org/view/10.24431_rw1k460_2020_7_24_181228

The size-at-age relationship of managed and commercially exploited marine fish is an important component of stock assessment models, with potential to affect estimates of spawning biomass, recruitment and management reference points. Pacific cod has highly variable growth rates, which makes individual ages based on length very hard to resolve. In the Eastern Bering Sea there is a discrepancy between cod mean length-at-age derived from otolith microstructure and the modes of length frequencies in survey data, particularly for fish that are less than 50 cm in length. Two unexplored hypotheses to explain the discrepancy are: cod growth rates change 1) over space and environmental gradients; 2) from cohort to cohort. Ageing samples in the surveys are taken on a length-stratified basis and some of the length categories (particularly ages 1−2) may get disproportionately sampled earlier in the survey. The biological and oceanographic data was collected gathered by the annual EBS shelf bottom trawl surveys. The datasets are a subset of the larger database housed by the Alaska Fisheries Science Center (AFSC) for the Eastern Bering Sea (EBS) shelf survey consisting of data collected specifically for Pacific cod from 1994-2016. Data are presented as four CSV files: PCOD_HAULCATCHDATA_NPRB1505.csv PCOD_SPECIMENDATA_NPRB1505.csv PCOD_LENGTHDATA_NPRB1505.csv goURL_lr_photoshop_fr.csv This dataset was generated as part of NPRB project 1505