Journal of the Marine Biological Association of India

Volume 32 Issue 1&2

Biometric analyses to identify populations of Ilisha melastoma (Schneider, 1801) from coastal waters of South India.

M. S. M. Sahubar Hussain and V. Ramaiyan

The present investigation deals with the analyses of deliminating populations of Indian shad lllsha melastoma based on morphometric characters. A total number of 828 specimens obtained during 1982 to 1983 from commercial catches from Madras, Porto Novo, Point Calimere, Mandapam, Tuticorin, Cape Comorin, Vizhinjam, Calicut, Mangalore and Karwar, were considered for this analysis employing 17 body measurements. The allometric equations were tested and the fitness was analysed by plotting a sample (male and female separately) and by calculating the correlation coefficient for all combinations of characters. Besides, 95% confidence zones were calculated taking the standard length as an independent variable and other characters as dependent variables. Though there were no significant differences between sexes at 95% confidence zones, statistical calculations of regression coefficients of all combinations of characters from nine stations showed significance at 5 % level in certain combinations which were eliminated from further intersample analyses. Based on the sum of the statistical differences between 17 parameters (in combinations) the samples were judged by the method of rejective limits of 25% probability level. These results suggest that although I. melastoma is found distributed all along the east and west coasts of  S. India, it tends to form localized stocks.

Date : 31-12-1990