Spatial and temporal variations of inshore demersal fishes in the Gulf of Gabes (Tunisia, Central Mediterranean Sea)

Abstract

In the Gulf of Gabes (South-east of Tunisia), the spatial and temporal variations of the demersal fishes communities were examined during two benthic trawl surveys conducted on July 2009 and July 2010 aboard a research fishing vessel. 16 sampling stations were surveyed on inshore bottoms, from 15 to 50 m depth. Seventy-five fish species belonging to two classes were recorded as follows: Elasmobranchii (8 spp.) and Actinopterygii (67 spp.). In the coastal area of the gulf, the inter-annual comparison of the abundance of the demersal fish fauna shows a significant improvement during the summer of 2010 compared to the summer of 2009. This increase is modelled in all surveyed locations especially, in Southern Kerkennah and in Eastern Djerba. This area appeared to be in a good ecological condition hosting an important variety of fish species associated with meadows of Posidonia oceanica and beds of the brown algae Arthrocladia villosa. The species’ compositions of the demersal fish assemblage showed clearly that the spatial and temporal analysis represented the differences of abundance of the fish’s assemblage during these two cruises (summer 2009 and summer 2010). These differences were closely related to peculiar characters of the fauna and biotopes (improving of bottom type and state of vegetation cover community).