The Mobile Fauna - Especially Gammaridea of Sargassum cymosum

Abstract

A comparative study was made on the composition of the vagile fauna inhabiting the alga Sargassum cymosum collected at 2 sites, differing in wave action, on the northern coast of Sao Paulo State, Braz~l (23"30'S and 45"06'W). A total of 122.886 specimens were collected at 2 stdt~ons, belonging to 23 taxonomic groups. Gammaridea comprised the dominant group at both sites. 15 species were recorded, among these 14 common specles. Water movement - even at the exposed shore - and sediment quantity of the sheltered site do not seem to affect gamrnaridean specles variety. Species dominance throughout the yedr varied In exposed and sheltered localities. Hyale medla was dominant at the exposed shore, and Amphilochus neapolitanus was the most abundant species at the sheltered shore.