Groundwater pre-treatment prevents the onset of chronic ulcerative dermatopathy in juvenile Murray cod, Maccullochella peelii peelii (Mitchell)

摘要

Chronic ulcerative dermatopathy (CUD) is a disfiguring condition affecting Murray cod cultured in untreated groundwater. This study sought to further investigate the possible etiology of the syndrome and determine whether groundwater pre-treatment could suppress the development of CUD in juvenile Murray cod. Electrolyte enrichment or pre-treatment with UV irradiation delayed the onset of CUD. In contrast, pre-conditioning of groundwater either in a vegetated earthen pond or in the presence of artificial macrophytes drastically reduced both the incidence and severity of CUD, with more than 90% of fish exhibiting no visual signs. Haematology and blood parameters were assessed for future diagnostic potential, but no changes in blood parameters were observed, even in advanced CUD-affected fish. This paper identified that the treatment of groundwater via an earthen pond and in the presence of an artificial macrophyte are two highly effective methods of preventing CUD arising in juvenile Murray cod.