Alterations in behaviour, scaphognathite oscillation and heart beat rate of freshwater prawn, Macrobrachium dayanum (Crustacea Decapoda), induced by cadmium chloride exposure.

Abstract

Alterations in behaviour, scaphognathite oscillation and heart beat rate of Macrobrachium dayanum exposed tocadmium chloride (CdCl2) were recorded. Bioassay tests were conducted to determine the LC50 values of the toxicant for 24, 48,72 and 96 h for males which were 0.24, 0.19, 0.17 and 0.15 mg/l while 0.24, 0.22, 0.17 and 0.16 mg/l for females, respectively.For acute toxicity studies, males were exposed to 0.15 mg/l (96 h LC50) while for sub-acute toxicity tests (25% of 96 h LC50)value of CdCl2 was 0.0375 mg/l. For acute toxicity observations, females were exposed to 0.16 mg/l (96 h LC50) and 0.04 mg/l forsub-acute studies. Variations in behaviour, scaphognathite oscillation and heart beat rate were recorded for both the sexes.Changes in aggressive behaviour and body colouration were more pronounced in males as compared to the females. Behaviouralchanges, scaphognathite oscillation and heart beat rate were significantly different in males and females. Variations in theseparameters may probably be due to the impairment in functioning of central nervous system (CNS) due to accumulation of theheavy metal in exposed prawns