BIOACTIVITY OF ECHINODERM ETHANOLIC BODY-WALL EXTRACTS - AN ASSESSMENT OF MARINE BACTERIAL ATTACHMENT AND MACROINVERTEBRATE LARVAL SETTLEMENT

The ethanolic body-wall extracts of 16 species of echinoderms from 16 genera were screened for their ability to affect the attachment of the marine bacteria Deleya marina (Baumann) and Alteromonas luteo-violace a (Gauthier). Body-wall extracts were tested at concentrations which m imic mean natural tissue concentration, 3.0 mg/ml seawater, and four h alf-log dilutions of this initial concentration. The extracts of three echinoderm species caused significant inhibition of bacterial attachm ent, while extracts of eight species caused significant enhancement of attachment. The body-wall extract of the asteroid Goniaster tesselatu s (Lamarck) displayed the most potent antimicrobial activity, complete ly inhibiting attachment of both bacterial species at a concentration of 3.0 mg/ml seawater. The ethanolic extracts of 20 echinoderm species were also tested at a similar range of concentrations for their abili ty to affect the settlement of cyprid larvae of the barnacle Balanus a mphitrite (Darwin), and coronate larvae of the bryozoan Bugula neritin a (Linne). All echinoderm extracts inhibited settlement of both barnac le and bryozoan larvae at the highest concentration tested (3.0 mg/ml seawater). Eleven of the 20 echinoderms tested (13 asteroids, 3 holoth uroids, 3 ophiuroids and a crinoid) had body-wall extracts that inhibi ted settlement of competent barnacle and bryozoan larvae at concentrat ions as low as 0.12 mg/ml seawater. These extracted echinoderm compoun ds may function as non-toxic or toxic antifoulants, and to promote bac terial surface colonization, which could be valuable to the organisms disease resistance.