Feeding ecology of the green crab, Carcinus maenas (L., 1758) in a temperate Estuary, Portugal

The feeding ecology of Carcinus maenas was studied between June 2003 and June 2004 in three areas in the Mondego estuary, Portugal. Samples were collected monthly, during the night, at high water of spring tides using a 2 m beam trawl. Among 837 stomachs examined, 25 different food items were identified. Crangon crangon, Hediste diversicolor, and Teleostei were the most important food items by occurrence, numbers, and weight. As an opportunistic feeder, differences in diet found between areas and seasons reflected prey availability. No differences were found in prey selection according to sex and carapace width of individuals. The feeding intensity of moulting and ovigerous crabs was lower. The incidence of cannibalism was higher than reported in the literature. C. maenas seems to be a main top predator in the food web of the Mondego estuarine ecosystem.