Toxicity evaluation of the holothrian Holothuria (mertensiothuria) leucospilota (Brandt) and The effect of toxin on the prawn Caridina rajadhari

Abstract

The evaluation of lethal and sublethal concentrations is an important step for further studies on behavioural and physiological changes in the animal. In the present investigation toxicity eveduation was done using computational procedure for critical analysis of the regression line relating probits and log dose. In the present study five size groups of the prawn Caridina rajadhari namely juveniles, immature females, immature males, mature females and mature males were used and the LC51, values were calculated upto 96 hrs. It was observed that the percent mortality of the five size groups increased progessively upto 96 hours in all concentrations of holothurian toxin and the LC^j values decreased with increasing exposure period. The size and sex dependent toxicity indicated that LCj,, values followed by immature male, immature female, mature male and mature female. It was observed that males were found to be more tolerant than females in both immature aand mature stages. It was also observed that mature females were most susceptible and the juveniles are more tolerant among the test animals.