Trends in penaeid shrimp landings by sona boats at Visakhapatnam Fishing Harbour, Andhra Pradesh

摘要

Sona boats operate mostly in the northern part of the Bay of Bengal up to sand heads. The boats (13-15 m OAL) worthy to conduct voyage fishing for 10-20 days exploit resources upto a depth of 100 m. The present study analysed the trends in penaeid shrimp landings by sona boats at Visakhapatnam Fishing Harbour, for the period from 2001 to 2010. During the period, annual fishing effort ranged from 4,77,710 to 16,31,507 h with an average of 10.15, 230 h. Annual penaeid shrimp catch varied from 1,409 to 7,496 t, average being 4,892 t. Average catch per hour (CPH) was estimated at 4.81 kg. Annual penaeid shrimp contribution from the sona boats to the total fish landings was 10.2 to 22% (average 15.9). Both fishing effort and penaeid shrimp catch showed increasing trend during the period. Penaeid shrimp fishery was supported by 14 genera/species dominated by Metapenaeus monoceros followed by Al. dohsoni. Mean annual species composition and CPH for each species were computed for two span, first being 2001-2005 and the second during 2006-2010. The CPH for the penaeid shrimps increased by 1.5% from span-1 to span-2. CPH for smaller shrimp species declined whereas increased for commercial species. Expected catch for each year estimated by Schaefer production model (CEDA; r(2) =0.72) showed underexploitation during 2001 and 2004; optimum state of exploitation for four years during 2005, 2006, 2007 and 2009 and overexploitation for four years during 2002, 2003, 2008 and 2010. In terms of total fish landings, 2001 and 2002 showed underexploitation, optimum state during six years i.e., 2003, 2006, 2007, 2008, 2009 and 2010; while overexploitation during 2004 and 2005. Considering the exploitation rate of both penaeid shrimps and total fish, by sona boats, the study suggests restriction of fishing effort at the 2009-2010 level to ensure sustainability of the resources.