Pelagic connectivity of European sea bass between spawning and nursery grounds

The sea bass stock around the UK (northern stock) has declined rapidly over past decade, likely due to a combination of both overfishing and low recruitment. Understanding mechanisms that drive number young reaching nursery grounds is important for explaining observed recruitment variability therefore developing effective management strategies. An individual-based model (IBM) been developed here investigate factors affecting settlement on northern stock. Simulations considered seven years with varying environmental conditions year class strength, outputs were compared empirical data from monitoring areas in Ireland. IBM includes hydrodynamics simulate drift eggs larvae, temperature-dependent growth mortality, behavior position water column. Comparison between ICES assessment abundance age zero fish showed similar temporal variability, but higher predicted 2018, lower peak 1997. reproduced general patterns interannual Thames estuary, performed less well some other regions. Further investigation needed understand differences modelled supply observations, as these could be uncertainties reproducing physical environment (e.g., currents, temperature) or biology spawning, behavior, mortality), uncertainty derived assessments collected grounds. Nevertheless, provides useful demonstration connectivity spawning grounds, showing regions are have greatest influence different estuaries, how may vary interannually. For example, sources western Channel Celtic Sea can larvae many areas, leading across Sea, into Irish Sea. However, depend more local areas. Solent estuary dependent within each year. With temperature-dependence growth, duration pelagic stage, results show potential timing, relation ocean temperatures,