(P645) Reproductive cycle of the freshwater fish,Notopterus notopterus under natural and heavy metal contaminated water system.
Kulkarni, Dr.Raghavendra*,1, 1 Department of Zoology,Gulbarga University,Gulbarga-585106(India), Gulbarga, Karnataka, India
ABSTRACT- The reproductive cycle of the freshwater fish,Notopterus notpterus was studied in either sex under natuaral and heavy metal exposed conditions.The heavy metal used under exposure are mercuric chloride,cadmium chloride and their combination.The fish were exposed to these heavy metals under sublethal concentrations starting the exposure during the preperatory phase and terminating during breeding phase.The toxicity for the heavy metals were determined for 96 hrs and sublethal concentrations were calculated.The results indicate that the mercuric chloride found to be highly toxic and its toxicity was reduced when it is combined with cadmium chloride.The reproductive cycle of the fish studied under natural conditions indicate that gonads both ovary and testis undergoes changes in four phases in one year period such as preperatory(January-March),prespawning(April-July),Spawning(August-September)and postspawning(October -December).The study was undertaken by determining the gonadosomatic index,hepatosomatic index,histology of the gonads and some biochemical contents such as protein,lipid and chlesterol in both the gonads and hepatic tissues.The results indicate that all these parameters exhibited reduction in their indices in the fish exposed to heavy metals affecting the process of gonadal recrudescence. The effect was extensive in the mercuric chloride treated while the combination exposure reduced the toxic effect of mercuric chloride,suggesting in natuaral aquatic body,though contaminants effect the physiology of fish,it is inthe lesser order of effect due to interaction of chemicals each other bringing reduction in the toxicity pattern and effect of individual contaminants.
Key words: Fish,Notopterus notopterus, Heavy metals, Gonadal cycle