The influence of physical and biological processes on the ichthyoplankton communities in the Gulf of Sirte (Southern Mediterranean Sea)

This paper represents the first study on the ichthyoplankton community structure in the Gulf of Syrte and on spatial distribution in relation to the environmental conditions and to the zooplankton abundance. The results are an important contribution for the future fisheries management in this unexplored but largely exploited area. Biological samples were collected by means of a Bongo40 net carried out in June-July 2008. In total, 1914 larvae were found and 1653 were identified. In particular, bathypelagic taxa were the most abundant, followed by demersal, mesopelagic, pelagic and epipelagic taxa. Egg and larvae taxa showed a patchwork distribution, influenced by oligotrophic conditions, bottom depth and oceanographic features. The obtained results suggest that the environmental forcings were able to transport the inchtyoplankton to productive areas. In fact, maximum fish eggs densities were found in coastal stations linked to the ATC inflow, whereas larvae were mainly concentrated in the east side of the Gulf, probably as a result of the advection by the anticyclonic circulation. Additionally, the distribution pattern of the total larvae density and of the different assemblages were well matched with the abundance of the zooplankton, probably determining final larval survival, growth and recruitment.