Modeling the Influence of Hydrodynamic Processes on Anchovy Distribution and Connectivity in the Black Sea

摘要

Dispersal mechanisms of Black Sea anchovy larvae (Engraulis encrasicolus ponticus) across the Black Sea were studied with an individual based anchovy larvae model embedded in a Lagrangian model using surface currents calculated from daily dynamic height topography maps of altimeter data during a period of three years (2001-2003). Particles representing anchovy eggs were released at different sites during June to August and their movement was tracked over time. Drifters were advected for 36 days, representing the time it generally takes for anchovy eggs to develop into juveniles. Each individual was subject to somatic growth whose temperature dependence was calculated from satellite derived sea surface temperature data.Model results indicate that larval dispersal in the Black Sea is strongly controlled at the basin scale by the Rim Current circulation and its two cyclonic basin-wide gyres. It is locally controlled by mesoscale eddies. Consistent with the observed circulation fields, a strong meridional transport exists from the northern to the southern coastal zone along the western coast and the central basin. The peripheries of both the western and the eastern cyclonic gyres are also associated with strong larval transport from the southern coast to offshore areas. Elsewhere the connectivity between different regions is not as well pronounced due to weaker and patchy current fields. Variability in the dispersal of larvae is considerable when comparing different years and seasons and should be taken into account when designing networks of Marine Protected Areas in the Black Sea.