<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"> Toxicity of Hg (II) to prawns <i style="">Penaeus monodon </i>and <i style="">Penaeus indicus </i>(Crustacea: Penaeidae) from Rushikulya estuary, Bay of Bengal </smarttagtype>

Abstract

Penaeid prawns belonging to size 35-55 mm TL and 55-75 mm TL were exposed to the five concentrations of Hg (II) in salinities 5, 15, and 25 <i style="">‰</i>. The values of LC₅₀ with 95% confidence limitfor 96 hours were 0.036 (0.032-0.041) and 0.042 (0.036-0.044) mg l^-1 for large size groups of<i style=""> P. monodon</i> and <i style="">P. indicus</i> respectively. The LC₅₀ decreased with increase of time period. Small size groups were more sensitive to mercury at lower salinities while large size groups were more tolerant at high salinities. <i style="">Penaeus monodon </i>was more sensitive to mercury than <i style="">P. indicus </i>at each salinity. Threshold limit for <i style="">P. monodon </i>and <i style="">P. indicus </i>was 0.016 and 0.024 mg l^-1 respectively.