Fluctuations of northeast Arctic cod catches: A review of possible sources

Fluctuations of northeast Arctic cod catches: A review of possible sources

O. Nakken

Fluctuations of northeast Arctic cod catches: A review of possible sourcesThis is part of Resiliency of Gadid Stocks to Fishing and Climate Change
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Description

Fisheries science was established to provide answers to the question of why fish catches fluctuate. The first explanation our previous colleagues came up with was that spatial displacements and migrations of fish related to changes in the environment (often temperature) were responsible for the experienced failures or successes of fishing. The discovery that year-class variations caused large fluctuations in stock abundance of cod and herring added considerably to our understanding and our ability to provide answers (Hjort 1914). Hjort and his coworkers established a sampling program of catches in the main Norwegian
fisheries for cod and herring (length, age, sex, maturity stage) and these data enabled Toresen and Østvedt (2000) and Hylen (2002) to estimate annual stock abundances and fishing mortality rates for respectively herring and cod for the entire twentieth century. This paper provides a brief review of the impact of changes in climate and environment as well as the effect of fisheries on the stock of northeast arctic cod. A far more comprehensive review of the subject for all Atlantic cod stocks is given in ICES (2006a).

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