Effect of food supplementation on the growth of an intertidal scavenger

Abstract

A manipulative field experiment was done to examine the effect of additional carrion on the growth and reproduction of the intertidal scavenging snail Nassarius dorsatus Roding at Coorooman Creek, Central Queensland, Australia. Separate from the manipulation, samples were taken monthly for 3 yr to determine the pattern of growth of N. dorsatus. Carrion was supplemented by altering chopped fish to snails in 3 pools for 1 h every 2 to 4 d for 3 mo; snails in 3 control pools were not offered additional carrion. N. dorsatus appeared to recruit throughout the year, grow rapidly and die within 2 mo after settlement, which is an extremely short life cycle compared with nassariids from higher latitudes. There was no significant difference in the mean size of N. dorsatus between treatments before supplementation and those 5 wk after it had ceased. During supplementation, snails in the experimental treatment were significantly larger and marked juveniles grew significantly faster than those in the control. It is suggested that the scavenging fauna of intertidal sandflats and mudflats may have a considerable capacity to absorb carrion and that bioturbation caused by increased densities of burrowing scavengers may affect the structure of soft sediment communities.