Incorporating Spawning Origins Of Pelagic Juvenile Cod And Environmental Variation In The Stock-Recruitment Relationship

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Recent studies modeling back-calculated birth date distributions of pelagic juvenile (0-group) cod (Gadus morhua) have indicated differential regional spawning components in waters off the west, north and east coasts of Iceland, in contrast to traditional paradigms of stock structure. The relative proportions of pelagic juvenile cod that were estimated to originate from these regional spawning components were hypothesized to vary in response to the inflow of Atlantic water from the main spawning grounds in the south to the North Icelandic shelf. We examine this hypothesis by analyzing annual (1970-1998) coastal current data in relation to the proportions of pelagic juvenile cod that were estimated to originate from the main spawning component off the southwest coast of Iceland. Additional variation in environmental and stock conditions were also examined in relation to the estimated abundance, mean lengths, and spawning origins of pelagic juvenile cod to enable a detailed analysis of the stock-recruitment relationship. Results from our study were placed in the context of spawning stock structure and recruitment prediction, and provided an understanding of the effects of environmental and stock conditions on variable recruitment levels in the Icelandic cod stock.