For each broad category of food item the “frequency of occurrence” (cf. Bowen, 1992) and the “percent composition” (cf. Hynes, 1950) were calculated. Bait was easily recognized and discarded. Food overlap between each pair of species was also calculated, based on the formula of Morisita (1959), modified by Horn (1966 apud Zaret & Rand, 1971: 340).