Seasonal burrowing behavior and ecology of aporrhais occidentalis (gastropoda : strombacea)

1. SCUBA observations and in situ tagging experiments were carried out on a population of Aporrhais occidentalis during 1973-1976. Seasonal changes in burrowing behavior were quantified by determining the percentage of tagged snails found burrowing each month. Gut content analyses were performed at monthly intervals to determine if the intensity of feeding activity fluctuates seasonally. Empty A. occidentalis shells were collected and examined for evidence of predation. 2. Specimens of A. occidentalis alternate between periods of epifaunal activity and infaunal quiescence. Tagged snails tended to remain burrowed from August through January, but were active on the surface of the substrate from February until late summer. Gut content analyses showed that the snails fed actively during their epifaunal period, but ceased feeding while burrowed. 3. Laboratory attempts to influence burrowing behavior by manipulating water temperature were unsuccessful. 4. Published observations on eastern Atlantic species of Aporrhais suggest that seasonal burrowing behavior may be characteristic of the genus.