Mortality rates and stock assessment of Metapenaeus monoceros along the Kakinada coast

Abstract

Instantaneous total mortality coeficent (q) in Melapetweus mwt~lceros has k n estimated from the length-freqllency distribution estimated to annual catch for the years 1974-1977 for both males and females. The estimates of Z based on Heincke's method, &ve~on and Ifolt method and cohort analysis are c1ase.r to each other. The estimate& of Z by these melkds indicate a gradual in- in the values from 1974 to 1977 w m p d i n g to the increase in fishing effort. The stirnates of Z W w db y ~muiativec atch-curve and atchcurve methods are closer to each other and bigher than those obtained by the other three methds. Reasom for t k e varia tiom are discussed. 'he estimates of natural mortality -dent (M) by hhing's method and Pauty's method are closer to cacb other. Based on the values of Z obtainad by kverton and Holt mcrhod (4.364 for males and 3.664 for females) a d the values of M obtained by hhing's method (2.42 for mates a J 222 for females) fishing martality coefficient (F) is eatimatod as 1.944 €or males and 1.444 for femalts during the years 1974-77. St& assessment by 'Surplus-yield' model and yield-per-muit model as well as Baranov's cptch quation and cubart analysis indimte that the st& is fisW just at he optimum level of exploitation and any further inaease in e€fm will & the catch per Mur of trawling.