Submitted to: American Fishery Society (Fish Health Section) Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 9, 1999
Publication Date: June 9, 1999
Citation: MITCHELL, A.J. LETHAL CONCENTRATIONS OF NICLOSAMIDE, METALDEHYDE AND HYDROTHOL 191 TO THREE INTERMEDIATE SNAIL HOSTS, MELANOIDES TUBERCULATA, PLANORBDELLA RIVOLVUS AND PHYSA SP., OF DIGENETIC TREMATODES.. AMERICAN FISHERY SOCIETY (FISH HEALTH SECTION) PROCEEDINGS. 1999. p.39. Technical Abstract: Controlling digenetic trematode infections in fish is a complex problem. Direct control of the parasite is expensive and rarely practical. Restricting or eliminating birds (the definitive host) or snails (the first intermediate host), has at best yielded limited success. Legal as well as practical and economic considerations cause trematode control studies to focus on the snails. Planorbdella trivolvus and Physa sp., two snails common to Arkansas waters, and Melanoides tuberculata, an exotic snail found in Florida, Louisiana and Texas waters (believed to be spreading), are known to serve as the first intermediate host for digenetic trematodes that can seriously effect the health of catfish and baitminnows. These three snails were subjected to three promising chemicals (niclosamide, metaldehyde and Hydrothol 191 at various concentrations. The Niclosamide results showed the most promise. At a concentration of 0.5 ppm in the water, niclosamide appeared to eliminate all three snail species in less than 72 hours. The M tuberculata and P. trivolvus were all killed in less than 72 hours 0.3 ppm but not at 0.1 ppm. Hydrothol 191 caused an immediate death-like state in all the snails but they recovered by the third day with 80% of the M. tuberculata and 60% of the P. trivolvus surviving at the highest rate ppm, a rate too high for practical consideration of further testing of this chemical. Metaldehyde also showed little potential as an aquatic molluscide. No Physa sp., P. trivolvus or M. tuberculata died after 7 days exposure to 375 mg metaldehyde pellets/141cm2 of bottom area, the highest rate tested.