Note
Sponges are the dominant organisms on many coral reefs and through feeding they may greatly reduce the concentration of suspended food particles. Retention efficiencies of the tubular sponges Aplysina lacunosa , Callyspongia vaginalis and Niphates digitalis were examined on a coral reef located in the Florida Keys. Replicate ambient and exhalant water samples were collected in situ from individuals of each species and analysed using two methods. Retention efficiencies of suspended particles (0.75-18 mm) examined using Coulter counter analysis were similar among the three sponge species, averaging 86%.