The measurement of hunger as a relative estimate of food available to populations of Nassarius pauperatus.

It is often difficult to estimate the amount of food available to an animal population, especially for species having unspecialised diets. The intertidal snail Nassarius pauperatus is omnivorous, feeding on both algae and animal carrion. Sampling the standing crops of carrion and algae was not thought to be a valid measure of the amount of food available to N. pauperatus. Instead, food availability was estimated indirectly, by measuring how hungry snails were.The percentage of snails feeding within 15 min of having been offered a meal of the bivalve Katelysia scalarina (Lamarck) was found to be a realiable and comparative estimate of food availability, and was measured in the field at 17 locations. The mean length of adult Nassarius pauperatus was negatively correlated with hunger, and at locations having high indices of hunger there was evidence of intraspecific competition for space to feed around items of carrion.These results are discussed and it is proposed that Nassarius pauperatus are surrounded by algal food of poor quality, with carrion being an important part of their diet for survival, growth and reproduction.