Stock assessment of the penaeid prawn Metapenaeus dobsoni (Miers) along the Indian coast

Abstract

The annual prodiction of M. dobsoni showed an increasing trend with an annual average of
22 370 t during 1985-S9. It formed 15.7% of the penaeid prawn landings in the country. West coast
contributed 69.9% to the annual yield of this prawn. Kerala ranked first (51.4%) in M. dobsoni
production followed b;' Tamil Nadu. Shrimp trawl alone caught 54% of the landings. L«> and K were
139 mm and 2.4 for m«les, and 145 mm and 2.76 for females respectively. The instantaneous mortality
coefficient (Z) ranged lietween 16,47 and 25.29 in males, and between 16.21 and 20.97 in females. Tlie
natural mortality coefficient (M) was 2.3 for both the sexes. The yield per recruit (Yw/R) increased
steadily to maximum values (MSY/R) in both the sexes at Emax ranging between 0.2 and 0.4. It
marginally reduced at Ihe present E between 0.8 and 0.9 suggesting that the resource is overexploited
and the current effort s far higher than the effort required to harvest optimum yields. Although the
average annual catch by shrimp trawls (12 189 t) is lower than MSY (13 965 t), the annual effort of
6 920 tpd or 1 488 000 bd (F= 17.8 and E = 0.89) is far beyond f^,. Considering the fact that this
prawn is also exploited by other gears with an annual average of 10 180 t during 1985-89, a conservative
estimate of 25 000 t as potential stock for the whole country is made