Treatments for Temnocephalids Ectosymbiont Craspedella sp. on Cherax quadricarinatus and Cherax albertisii “Papua Freshwater Lobster”

Abstract

There were two species of crayfish “red-claw” (Cherax quadricarinatus) and “blue-huna” (Cherax albertisii) for their aquaculture potential. Crayfish were susceptible to fungal (crawfish plague), parasitic (protozoa and nematodes), and bacterial pathogen. A number of ectosymbiont Craspedella sp. have been observed on red-claw and blue-huna. The flatworms were commonly found almost in the whole body, on the upper exoskeleton behind the head, in the gill cavity and on the claws and underside of crayfish. Although their number sometimes was very high, they didn’t cause any problems especially for the new molting crayfish. Micro organisms living on the crayfish surface body and worms didn’t cause any pathological changes. Adults Craspedella sp. can be eliminated by a short bath in salt water or formaldehyde 37% solutions for several hours. This treatment didn’t kill worm eggs, so it needs to be repeated every one week. Moreover, hyposalinity or OST (Osmotic Shock Therapy) is one of the most effective therapies for ectoparasites on Craspedella sp. with dose of bath treatment 15 grams per litre of salt (15 ppt) for more than 3 hours, and dipped in salt water at 30 ppt (or 3.0 ppm, seawater salinity) for 15 - 20 minutes.