Abstract
Fish diseases are as old as the beginning of Clarias gariepinus aquaculture in Nigeria. It did not pose so much threat at that time. The proliferation of fish farms by private investors, after the NEPAD Fish for all Summit in 2005, the intensive culture of fish, and increase in the production of Clarias spp. brought it s diseases to the fore . The lack of proper farm management practice which included slack of strict observance to Hazard Analysis of Critical Control Points (HACCP), led to an upsurge in disease occurrences. Investors were quick to seek solutions to safe guard their investments , hence the use of antibiotics and chemicals such as malachite green, potassium permanganate copper sulphates, etc . The uncontrolled use of antibiotics was so much that research identified residual antibiotics in fish products that could cause drug resistance in human beings. Again some of the chemicals were found to be cancer inducive . The identification, treatment, and documents of fish diseases by veterinary doctors working with fisheries officers commenced, and awareness was created amongst fish farmers especially through their associations and cooperatives. This led to the gradual establishment of a disease reporting system. It was found that the disease occurrence was more because of poor farm management especially water management, unconscious use of adulterated feeds, poor genetic fish strains which made the fish easily susceptible to infections. Other sources of contamination identified included the bulk packaging of starter feeds which many breeders c ould not exhaust in one or two hatching thereby resulting to storage .
FAO had recommended the use of salt in Clarias gariepinus fish farming and identified the chief cause of fish diseases as Aeromonas hydrophila . A severe attack by Aeromonas hydrophila thrives in heavily polluted water. The bacterium has been identified as the single most causative factor of mortality in aquaculture , which dies at 1. 5% saline solution. The preventive and curative use of saline solution for the control of fish diseases depend on the percentage saline solution from 0.5%-2%; exposure time of some seconds to 30 minutes; the size of the fish from fry to adult fish; and the degree of infection. This takes care of bacteria, fungal and parasitic diseases in Clarias fish.
The saline solution kills the bacteria by osmosis immediately unlike drugs that take time to act. It was found that salt is the most potent substance as against the use of chemicals and antibiotics. The salt equally improves the immunity of the fish.
KEYWORDS: Management, fish disease, saline solution, aquaculture