Peanut Crab Pinnotheres halingi, a symbiotic commensal or parasite of Sandfish Holothuria scabra?

Abstract

High mortality of sandfish Holothuria scabra broodstock is one of the main problems in sea cucumber hatcheries. Broodstock collected from wild are very difficult to keep alive for long periods because the broodstock readily eviscerate. One cause of evisceration and death is probably due to the presence of peanut crabs Pinnotheres halingi in body cavity as commensal. This study aimed to analyse the mortality of sandfish due to the presence of peanut crabs as commensal. Sandfish samples were collected in Liukang Tupabbiring Utara District, Pangkep Regency in South Sulawesi, Indonesia. During the study, 139 sandfish were observed in rearing nine tanks at the laboratory. The results of this study are not strong enough to state that peanut crab is a symbiotic commensal or parasite. The peanut crab is thought to have turned into a predator when it starved. Peanut crab malignancy as a predator can cause the death of 139 sandfish in 92 days. This is thought to be the reason why broodstock is very difficult to rear for a long period in a controlled tank in a laboratory or hatchery.