New publication: Recruitment signals in juvenile cod surveys depend on thermal growth conditions

By Benjamin J. Laurel, David Cote, Robert S. Gregory, Lauren Rogers*, Halvor Knutsen*, Esben Moland Olsen* in Canadian Journal of Fisheries and Aquatic Sciences


Coastal seine surveys contain some of the only direct measures of age-0 abundance for Atlantic cod (Gadus morhua) and Pacific cod (Gadus macrocephalus), yet their utility in forecasting future year-class strength has not been evaluated among regions. We analyzed coastal time series from the Gulf of Alaska, Newfoundland, and Norway to test the hypothesis that recruitment signals are stronger when assessed under thermal conditions that provide high juvenile growth potential. Weaker recruitment signals were associated with low growth potential from cold winters (Newfoundland) and recent warmer summers (Norway). We conclude that temperature-dependent growth strongly influences the utility of coastal surveys in recruitment forecasting among regions. Temporal changes in growth potential (e.g., via climate change) will likely affect recruitment signals by way of changes in juvenile mortality or spatial shifts to more favorable thermal habitats.

Canadian Journal of Fisheries and Aquatic Sciences
2017, 74(4): 511-523
Published on the web 6 September 2016
DOI: 10.1139/cjfas-2016-0035
Publication webpage.

* Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, UiO.
See the publication webpage for full author information.

Tags: Canadian Journal of Fisheries and Aquatic Sciences;
Published May 19, 2017 10:22 AM - Last modified May 19, 2017 10:23 AM