European Journal of Biotechnology and Bioscience

Authors
Vinod Kumar M, Kiran S Mali, Farejiya MK, Rama Rao K

Abstract
Age growth and mortality parameters were analysed for long tail tuna, Thunnus tonggol exploited along the North West coast of India based on the data collected though the fish landing centers during 2004-2012. Size range Fork length of the species was between 22-86 cm and the weight was from 150-6250 gms. Von Bertalanffy equation for growth in length was fitted for length-at-age data for estimating L∞, K and t_o. The asymptotic length (L∞) was 98.65 cm, growth co-efficient (K) was 0.39 per year and age at zero length (t_o) was -0.34. The natural mortality (M), fishing mortality (F) and total mortality (Z) estimated as 0.49, 0.73 and 1.22 respectively. The length-weight relationship calculated with the equation W=aL^b and the value obtained as W is equal to 0.0538 L^2.65. The correlation co-efficient (r²) derived in the study was 0.96. M/K ratio in the present study was 1.8 and the exploitation ratio F/Z was 0.42.