Feeding Ecology of Nereis diversicolor (O.F. Müller) (Annelida, Polychaeta) on Estuarine and Lagoon Environments in the Southwest Coast of Portugal

The feeding ecology of Nereis diversicolor (O. F. Müller, 1776) (Annelida: Polychaeta) was studied over 14 months at three estuarine-lagoon systems of the Southwest coast of Portugal (Odeceixe, Aljezur and Carrapateira). The analyses of digestive tract revealed that diet change according to site, period of the year and individual sizes. There are no differences in the digestive contents between sexes. In all sampling stations a total of thirty items were found, but only five shown an occurrence superior to 1%. These were: mucus (56.3%), sand (17.6%), vegetable detritus (10.7%), Nereididae (7.7%) and Corophium sp. (1.8%). N. diversicolor was detected in all sampling stations with a filter-feeding behaviour, although in Carrapateira there is evidence of slightly higher carnivore behaviour than in Odeceixe and Aljezur. Mucus (a food complex including organic matter, bacteria, fungi and phytoplankton) was the main gut content.