Seasonal variation of assemblage fauna to Ophioplocus januarii (Echinodermata: Ophiuroidea) in Golfo San José, Patagonia

ARRIBAS, LORENA P.; PENCHASZADEH, PABLO E.; BRÖGGER, MARTÍN I.

Melbourne, Estados Unidos

Congreso; Fifth North American Echinoderm Conference; 2008

Mixed substrate composed by tuff and sand at Golfo San José (Patagonia) shelter a high biodiversity. In this study, the fauna living with the ophiuroid Ophioplocus januarii was analyzed and related to seasons. Random samples were seasonally collected over 50 square centimeters at subtidal area in Playa Villlarino between December 2005 and August 2007. The fauna was identified and grouped in different taxonomic levels, observing a dominance of Mollusca (mainly Trochidae and Mytilidae), Polychaeta (mostly Nereidae), and within Crustacea, most frequent groups were Amphipoda (Lysianassidae and Phoxocephalidae) and Leptostraca, with less abundance of Isopoda and Ostracoda. Differences in abundance of rock-boring and sandy species were observed, which can be related to the proportion of hard /soft substrate sampled in each season. The abundance of O. januarii was highly variable through the studied period. Considering this peculiar environment, with frequent storms and wide range of tides, is not possible to ascribe this variations to a natural seasonal condition.