Fishery and biology of Plesionika quasigrandis Chace, 1985 off Sakthikulangara, south-west coast of India

Abstract

The fishery and biology of Plesionika quasigrandis Chace, 1985 from Sakthikulangara Fishing Harbour was studied for the period 2006-2008. The average annual catch was 2400 t, forming 28% of the total deepsea shrimp landings at Sakthikulangara. August to November was the most productive period in terms of catch and catch rate. The growth parameters L∞ and K y-1 for males and females were 124 mm, 0.7 and 130 mm, 0.8 respectively. The growth performance index (φ’) and t0 were 4.032, -0.0036 and 4.131, -0.00275 for males and females, respectively with a longevity of 5 years. Recruitment pattern was bimodal with two peaks, one in March and the other in June. The relationship between total length (TL) and total weight (W) revealed an isometric growth in case of females and allometric growth in males. The length at recruitment (Lr) and length at 50% capture (Lc50) was 73; 84.8 mm (males) and 78; 93.4 mm (females), respectively which corresponded to an age (tc) of 1.6 years. The natural mortality, fishing mortality, total mortality, exploitation ratio, exploitation rate and Emax were 0.81, 2.14, 2.95, 0.62, 0.72, 0.90 and 0.88, 2.97, 3.85, 0.71, 0.77, 0.93 for males and females, respectively. The rate of exploitation for P. quasigrandis was found to be lower than the Emax which indicates sustainable utilisation of the resource.