Evidence for directed fishing effort in North Sea cod and haddock stocks

Fishing mortalities at age in North Sea cod, haddock, and whiting are examined in relation to biomass of fish at each age. For cod and haddock highest fishing mortalities are associated with high biomasses. For haddock this means the exploitation pattern changes from year to year because recruitment is very variable. For cod more stable recruitment results in a consistent exploitation pattern. The implications for stock assessment are discussed.