Temporal patterns in cephalopod catches and application of non-equilibrium production model to the cephalopod fishery of Karnataka

Abstract

Non-equilibrium production models were fitted to cephalopod catch and effort statistics to arrive at limit reference points (LRP), <i>Y_MSY</i> and <i>f_MSY</i>. The parameter estimates, <i>K (carrying capacity), r (intrinsic rate of population growth) </i>and <i>q (catchability coefficient)</i> were 93,677 t, 0.403 per year, 8.614E-08 for Schaefer model. Estimated precautionary limit <i>Y_MSY</i>_, was 9,446 t and the corresponding <i>f_MSY</i> was 24,94,611 h. Despite the fact that the 2007 catches are currently around the <i>Y_MSY</i>, the current effort, <i>f_now</i> expended in the trawling ground is 29,32,214 h for a trawling period of 97.4 h per multi-day fleet (MDF) trip. Fishing effort is 28% in excess of the precautionary target, <i>f_0.1</i> estimated at 21,07,060 h as well as 20% above the LRP for sustaining the fishery at MSY levels. It is recommended that trawling effort for the MDF be reduced so that the long-term catches of cephalopods correspond to the <i>Y_MSY</i> levels in the present fishing area.