Length-weight relationship in three species of silverbellies from Chennai coast

Length-weight relationship in three species of silverbellies - Photopectoralis bindus, Secutor insidiator and Gazza minuta was studied based on the data obtained from 742, 862 and 1900 samples of each species respectively, collected during the period January 2004 -February 2006. Analysis of covariance revealed no significant difference between males, females and indeterminates in all the three species. The coefficients ‘a’ and ‘b’ of the LW equation were derived as 0.000011989 and 3.0515 for P. bindus, 0.00002369 and 2.905 for S. insidiator and 0.00002088 and 2.9228 for G. minuta. Statistical test for isometric growth (H0:b=3) carried out using student’s ‘t’-test on the regression coefficient ‘b’ revealed that the values of b estimated for the three species do not deviate significantly from the isometric value of ‘3’ at 5% level

First report on the philopatric migration of bull shark, Carcharhinus leucas in the Pulicut lagoon

Bull sharks Carcharhinus leucas were captured by a modified gillnet, made of cotton twine from Pulicat lagoon during 2005-06. The bull sharks exhibit unique philopatric behaviour in the lagoon for parturition. The four specimens caught were all pregnant. The value of the sharks ranged from Rs. 20000-22000

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Not AvailableBull sharks Carcharhinus leucas were captured by a modified gillnet, made of cotton twine from Pulicat lagoon during 2005-06. The bull sharks exhibit unique philopatric behaviour in the lagoon for parturition. The four specimens caught were all pregnant. The value of the sharks ranged from Rs. 20000-22000.Not Availabl

Reproductive biology of the Rabbitfish (<i>Siganus canaliculatus</i>) in the Gulf of Mannar region, India

131-140Rabbitfish, Siganus canaliculatus were collected from the Mandapam area of the Gulf of Mannar region between November 2000 and October 2002. Mean sex - ratio was dominated by the females throughout the year except in September and October. Frequency distribution of mature males and females in different length groups showed that 50 % of males and females attain maturity at 132 mm and 139 mm of total length respectively. The gonadosomatic index (GSI) and condition factor (Kn) values revealed that the spawning takes place between November and March with a peak in January. Regression analysis of Fecundity (F) with total length, total body weight and ovary weight was - 872709.4 + 5940.21 TL (r = 0.9916), - 30839.4 + 3155.7 BW (r = 0.9998), - 116711.19 + 50566.9 OW (r = 0.9949) respectively

Age and growth studies on white-spotted rabbitfish <i>Siganus canaliculatus </i>(Park), from the Gulf of Mannar region South India

427-433Age and growth of white-spotted rabbitfish Siganus canaliculatus (Park), were determined from the Gulf of Mannar region, South India based on the length frequency data collected. Estimation of Lα and K were 245 mm and 1.6 and 245 mm and 0.6 for Gulland and Hold and ELEFAN – I methods respectively. Growth parameters of von Bertalanffy’s equation was computed Lt = 245 [1-e- 1.656 (t+.0171)].  Longevity estimation based on Gulland and Holt plot and ELEFAN – I methods were 1.81 yrs and 4.47 years respectively

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Not AvailableLength-weight relationship in three species of silverbellies - Photopectoralis bindus, Secutor insidiator and Gazza minuta was studied based on the data obtained from 742, 862 and 1900 samples of each species respectively, collected during the period January 2004 -February 2006. Analysis of covariance revealed no significant difference between males, females and indeterminates in all the three species. The coefficients ‘a’ and ‘b’ of the LW equation were derived as 0.000011989 and 3.0515 for P. bindus, 0.00002369 and 2.905 for S. insidiator and 0.00002088 and 2.9228 for G. minuta. Statistical test for isometric growth (H0:b=3) carried out using student’s ‘t’-test on the regression coefficient ‘b’ revealed that the values of b estimated for the three species do not deviate significantly from the isometric value of ‘3’ at 5% level.Not Availabl