An Evaluation Of Recruitment Indices For Northeast Arctic Cod (Gadus Morhua L.)

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Indices of the abundance of Northeast Arctic cod (Gadus morhua L.) for various life stages were compared in order to determine the earliest stage at which year-class strength is established. The indices considered are: VP A estimates of spawning stock biomass; an egg abundance index; an early juvenile (approximately three-months old) abundance index; 0-group (age four to five months) abundance indices; bottom trawl and acoustic survey abundance indices for one, two and three- year-old cod and VP A estimates of the abundance of three-year-old cod. Based on a regression analysis, the relative abundance of early juvenile cod was the first life stage that was correlated with their relative • abundance as three year olds. Since the correlation between the estimates of spawning stock biomass or total egg production and the relative abundance of three-year-old cod was weak, it is concluded that considerable yearly variation in mortality occurs before cod reach the early juvenile stage.