Seasonal changes in a sandy beach fish assemblage at Porto Pim, Faial, Azores

A shallow-water fish assemblage, over a soft, sandy substratum at Porto Pim Bay on the island of Faial, Azores, was sampled at monthly intervals with a beach seine. Sampling was undertaken at 3-h intervals over 24 h on a monthly basis between July 1989 and June 1990. There was seasonal variation in the density of individuals and biomass with the highest values in summer (1•4 m−2 and 27•75 g m−2 respectively). A total of 24 species were observed and the assemblage was dominated by four species (Chelon labrosus, Sardina pilchardus, Pagellus bogaraveo, Trachinotus ovatus). Species diversity (H′) was high throughout the year but equatability (J) was low, due to the dominance of a few species. The largest change in the assemblage structure occurred between March and April. Only a few species could be classified as resident, with the two predators (Dasyatis pastinaca and Echiichthys vipera) being abundant at different times of the year. Most of the species observed were juvenile fish, many with an offshore distribution as adults, using Porto Pim Bay as a nursery ground.