Length-weight relationship and relative condition factor in Macrobrachium (Hellex)

The length-weight relationship was calculated for the freshwater prawn Macrobrachium idae. About 150 specimens of M. idae (males 50, females 50 and 50 juveniles) were utilised for this study. The length-weight relationship was assessed separately for males, females and indeterminants. The regression equation for males, females and indeterminants showed significant differences whereas it was insignificant for males and females. The variations in length-weight relation between sexes and indeterminants were compared and discussed. The relationship between total length with carapace length and total length with rostral length were also determined

Population dynamics and stock assessment of Delegoa threadfin bream, Nemipterus bipunctatus (Nemipteridae), from the Wadge Bank, South India

Fishery, population characteristics and stock estimates of Nemipterus bipunctatus were studied during June 2015 to May 2016 from Wadge Bank, South India. This region is characterised by rich biodiversity and has a conducive influence of the Indian Ocean and Arabian Sea. The asymptotic length (L?), growth coefficient (K) and arbitrary origin of growth (t0) were estimated as 30.5 cm, 0.85/year and 0.18 respectively. The mortality parameters, total mortality rate (Z), fishing mortality rate and natural mortality rate (M) were estimated as 2.20, 0.95 and 1.25 respectively. Exploitation ratio (E) was found to be 0.57 which showed marginal over exploitation of the species at Wadge Bank. This species has two recruitment seasons, one major season from October to December and another minor season in August. The length structured Virtual population analysis revealed heavy fishing pressure on the length group 24 to 28 cm and hence the delegoa threadfin bream was not found to suffer due to recruitment overfishing in Wadge Bank. Estimated total stock, Maximum Sustainable Yield (MSY) and annual catch were 5625.9348 tonnes, 1935.321t, 2419.152t respectively. Present level of Exploitation rate (U) and Exploitation ratio (F/Z) were estimated to be 0.43 and 0.57 respectively. The study infers the cod end mesh size of the trawls operated at Wadge Bank coast has to be increase from 10 to 25 mm to increase the yield per recruit, the effort could also be maintained as the exploitation ratio of 0.50 to have maximum yield per recruit. The study suggests reducing the present level of effort by 8 percent may be needed to sustain the stock of N. bipunctatus in Wadge Bank, South Indi

Food habits and feeding intensity of finlet scad <i>Atule mate </i>(Teleostei) <span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">off Gulf of Mannar, southeast coast of India</span>

307-311<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">Atule mate <span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">exhibits two types of feeding patterns, the juveniles feeding mainly on crustaceans and the adults exclusively on fishes. Low intensity of feeding was observed in juveniles, males and females. Juveniles had high diet breadth (2.86) when compared to the males (1.86) and females (2.10). The overlap studies showed clustering of high overlaps in the younger and older length groups. The dendrogram of the diet at various length groups showed two principal clusters, one at 91-150 mm (TL) length group and another at 151-280 mm (TL) length group. As per the cluster analysis two types of food patterns are evident in this species.</span