Abreu, S. Characterization of the ichthyofauna associated with sandy substrates off the Central Algarve

Benthic communities on soft-bottoms were sampled off the Algarve central coast, between April and September 2005, using a beam trawl. The sampling of the study area, between Faro and Portimão, was stratified by zone, depth and season of the year. In the 88 trawls realised, a total of 4072 individuals were collected and 65 taxa identified. Bothidae, Soleidae, Gobiidae e Serranidae contributed most to the total capture, with the first two families showing the highest values of abundance and biomass. Arnoglossus thori, Microchirus boscanion, Serranus hepatus, Arnoglossus laterna e Gobius gasteveni were the most important and common species. The lack of knowledge of this kind of habitat was revealed by the presence of some species not described previously for the study area. Differences were found between depths of 0-10 m in comparison with the 20-30 m interval. Although, the highest values of abundance and biomass were recorded at depths of 20-30 m, diversity was higher at the depth of 0-10m. No significant differences were found between Spring and Summer. Only some differences in density or in diversity of few species by sampling station were found, slightly higher values of diversity were found in Spring. At the Faro site, fish communities were mainly dominated by the family Bothidae while at Portimão were mainly dominated by family Soleidae. At Albufeira and Armação de Pêra sites, both communities were dominated by Bothidae and Serranidae, the last one being more relevant comparing with other sites. Soleidae and Gobiidae were also important at this sites. The factors which better explained the distribution of species in the study area were spatial variability and depth associated variability, while seasonal variability was reduced.  The high number of species identified and the representativity of the sampling make this study an important contribution for the biodiversity knowledge off the Algarve central coast.