Modelling larval dispersal of Pecten maximus in the English Channel: a tool for spatial management of stocks.
Résumé
The king scallop (Pecten maximus) is one of the most important benthic species of the English
Channel as it constitutes the first fishery in terms of landings in this area. To support strategies of
spatial fishery management, we developed a high-resolution biophysical model to describe scallop
dispersal in English Channel and to quantify the relative roles of local hydrodynamic processes,
temperature dependent planktonic larval duration (PLD) and active swimming behaviour (SB) on the
connectivity between 18 stocks identified from different sources (e.g. ICES data, VMS data). The
English Channel currents and temperature were simulated for 10 years (2000-2010) with the MARS-
3D code and then used by the Lagrangian module of MARS-3D to model the larval dispersal
pathways.
Results were analysed in terms of larval distribution at settlement, the larval retention rate and the
self-recruitment rate, two metrics commonly reported in studies on local populations’ persistence, and
connectivity among stocks. Furthermore, the connectivity among areas within a stock was assessed in
detail on the examples of the two main stocks in the English Channel (i.e. Bay of Saint Brieuc and Bay
of Seine) for which the distribution of scallops is well documented from annual stock surveys. While
larval transport in the English Channel depends both on the tidal residual circulation and the wind