A Review on Fish Disease Research in Assam, India

Abstract

Assam located in the North eastern region of India, has vast fisheries resources (totaling of 286,260ha). Fish disease has emerged as an important constraint in fisheries and aquaculture in the state. Available literature suggests that Epizootic Ulcerative Syndrome (EUS) caused by Aphanomyces invadans (proposed as Epizootic Granulomatous Aphanomycosis or EGA in 2005) was the most frequently encountered fish disease in the state. The outbreak of EUSin India reportedly started from the Barak valley of Assam and Tripura in 1988. Saprolegniasis (by Saprolegnia parasitica) was less frequent/ lethal fungal disease than EUS. Most commonly encountered bacterial fish diseases of Assam were infectious abdominal dropsy (by A. hydrophila), followed by fin & tail rot disease (by Pseudomonas fluorescens and A. hydrophila), ulcer disease (by Aeromonas spp. and Pseudomonas spp.) and eye disease ofcatla (by Aeromonas liquefaciens).Argulosis (by Argulus foliaceus), Lernaeosis (by Lernaea cyprinacea), Dactylogyrosis & Gyrodactylosis (by monogenetic trematodes Dactylogyrus and Gyrodactylus sp.), Ichthyophthiriasis (by Ichthyophthirius multifiliis) and Trichodiniasis (byciliate protozoan Trichodina sp.) were other parasitic diseases reported from Assam. Argulosis recorded the second highest incidence rate in aquaculture ponds of the state after EUS. A few cases of nutritional diseases like pin-head syndrome, lordosis and scoliosis were reported from culture ponds. Environmental diseases like asphyxiation, gas bubble disease and acidosis have also been reported from the state. The need to carryout more intensive and coordinated research covering all aspects of fish disease has been discussed in the paper.