DIGESTION RATES OF PREY EATEN BY INTERTIDAL SEA-ANEMONES FROM THE SOUTH-WESTERN CAPE, SOUTH-AFRICA

Digestion rates were determined for natural prey items offered to each of seven species of sea anemones found at Wooley's Pool in False Bay and to the single species (Bunodactis reynaudi) recorded at Blouberg o n the Atlantic coast of the south-western Cape, South Africa. This:was done by examining prey items removed-from the coelenterons at regular intervals after feeding and assessing their degree of digestion accor ding to a predetermined scale. There was considerable variation in the gut retention times between different anemone species offered the sam e prey types, with Actinia equina consistently showing the shortest gu t retention times (12 h for amphipods, 15 h for pelecypods and 23 h fo r isopods). Of the various prey categories tested, amphipods tended to be the most rapidly digested group, while molluscs and echinoderms us ually remained in the coelenteron the longest. Mean gut retention time s in B. reynaudi, the only species found both in False Bay (17 degrees C) and on the cold west coast (12 degrees C) were markedly longer (72 vs 60 h and 43 vs 30 h for pelecypods and gastropods respectively) at the lower temperature.