USE OF TROPICAL CLEANER FISH TO CONTROL THE ECTOPARASITE NEOBENEDENIA-MELLENI (MONOGENEA, CAPSALIDAE) ON SEAWATER-CULTURED FLORIDA RED TILAPIA

The juvenile bluehead wrasse (Thalassoma bifasciatum), the neon goby ( Gobiosoma oceanops) and the cleaning goby (Gobiosoma genie) were evalu ated for their abilities to remove ectoparasitic monogeneans (Neobened enia melleni) from seawater-cultured Florida red tilapia. Initial and final infection levels (number of monogeneans/fish) were monitored for individual tilapia maintained with and without cleaner fish in three 8-day trials. Initial infection levels varied widely among trials, wit h averages (+/- s.e.) of 412 +/- 103, 103 +/- 45 and 291 +/- 130 in tr ials 1, 2 and 3, respectively. Final infection levels on tilapia maint ained without cleaners (controls) were significantly (P < 0.05) higher than initial levels in trials 1 (1480 +/- 163), and 2 (275 +/- 50), b ut not in trial 3 (464 +/- 154). Although monogeneans were found in th e guts of all three species of cleaners at the end of each trial, the neon and cleaning gobies displayed superior cleaning abilities to the bluehead wrasse. Cleaning gobies reduced infection to 18.8, 1.1 and 41 .2% of control levels, while neon gobies reduced infection to 27.8, 13 .8 and 49.4% of control levels in trials 1, 2 and 3, respectively. Bot h goby species reduced infection to levels significantly (P < 0.017) b elow those of the controls in trials 1 and 2. Bluehead wrasse reduced infection to 47.0, 50.2 and 29.7% of the control levels in trials 1, 2 and 3; however, these differences were not significant (P > 0.05). Th e results demonstrate that cleaner fish, particularly the gobies, may be a viable biological method for controlling monogenean parasitosis i n seawater-cultured tilapia.