BIO PHYSICAL MODELING OF THE EARLY-LIFE STAGES OF HADDOCK, MELANOGRAMMUS-AEGLEFINUS, IN THE NORTH-SEA

An individual-based modelling approach was developed to investigate th e spatial and temporal patterns in the recruitment processes of North Sea haddock, Melanogrammus aeglefinus. The approach was based on the r ealization that the survivors to recruitment of an annual cohort are m ost probably not drawn at random from the initial population of eggs, but represent the fastest-growing individuals. Individual growth rates reflect the unique exposure of each larva to the environment along it s drift trajectory. In this context, the environment refers to a wide range of factors affecting growth such as food, turbulence and tempera ture. A combination of a model of egg production by the adult stock, a particle-tracking scheme, and a model of larval growth and mortality rate was used to simulate the dispersal trajectories, and the survival of haddock larvae spawned at different times and locations on the con tinental shelf. The particle tracking was driven by flowfields from a climatological implementation of the Hamburg Shelf-Ocean Model (HAMSOM ) for the North Sea and NE Atlantic. The system was able to resolve sp atial and temporal patterns in the recruitment process and indicated t hat the surviving population of larvae was drawn from a restricted par t of the spawning distribution. The results have the potential to guid e the development of future conservation measures in fisheries managem ent.