The gowth of larval cod and haddock in the Irish Sea: a model with temperature, prey size and turbulence forcing

摘要

We applied a physiological individual-based model for the foraging and growth of cod (Gadus morhua) and haddock (Melanofframmus aeglefinus) larvae, using observed temperature and prey fields data from the Irish Sea, collected during the 2006 spawningseason. We used the model to estimate larval growth and survival and explore the different productivities of the cod and haddock stocks encountered in the Irish Sea. The larvae of both species showed similar responses to changes in environmental conditions (temperature, wind, prey availability, daylight hours) and better survival was predicted in the western Irish Sea, covering the spawning ground for haddock and about half of that for cod. Larval growth was predicted to be mostly prey-limited, but exploration of stock recruitment data suggests that other factors are important to ensure successful recruitment. We suggest that the presence of a cyclonic gyre in the western Irish Sea, influencing the retention and/or dispersal of larvae from their spawning grounds, and the increasing abundance of clupeids adding predatory pressure on the eggs and larvae; both may play a key role. These two processes deserve more attention if we want to understand the mechanisms behind the recruitment of cod and haddockin the Irish Sea. For the ecosystem-based management approach, there is a need to achieve a greater understanding of the interactions between species on the scale a fish stock is managed, and to work toward integrated fisheries management in particular when considering the effects of advection from spawning grounds and prey-predator reversal on the recovery of depleted stocks.