Salt tolerance in mud fish (clariasliocephalus): implications for their domestication.

Abstract

Survival test conducted to determine the effect of salt toxicity on the survival, and the weight loss effect of salinity in mud fish juveniles. The study was conducted at Bushenyi district laboratory for a period of 2months. Samples were collected from the natural environment followed by laboratory acclimatization, salt treatments preparation and experimental setup, and finally introducing the randomly selected fish samples into the experimental tanks containing the differing saline concentrations and the experiment was run for 48hours For survival test, each tank was examined to count the number of mortalities and the results were recorded daily. For the weight test, samples were weighed before and after treatment. On introduction into the treatments, fish treatments, fish frequently tried to jump out of the fish holding tanks and showed heightened activity indicated by rapid to and fro movement and vigorous swimming of the fish. With time,(i.e.between0.5to2hours)fish gradually became lethargic, and showed erratic movement; developed muscle spasm and body convulsions, they tended to settle to the bottom of the tank (i.e. between 6 to 10 hours) and later they were found to swim on their back or lateral side with occasional body jerking and later started to die (i.e. between 8 to 12 hours) especially at high concentrations(8.0, - 12g/L). There was no significant difference in survival between salinity concentrations (0.00g/l, 1.5g/l,2.8g/l, 4.1g/l ,5.4and6.7g/l;(p>0.05)); whereas a significant difference in survival was observed between all the above concentration with concentrations 8.0g/l and 9.9g/l(p<0.05). There was no significant difference in weight before and after the test in all the concentrations The salinity significantly influenced survival of mud fish fingerlings where by salt concentrations had an effect on the survival of the mudfish fingerlings therefore increase in salinity levels and the time of exposure resulted into decrease in survival.