On the stock assessment of Parailia pellucida (Schilbeidae)in the Cross River Nigeria
The growth, mortality rates and the fisheries yield of Parailia pellucida (Schilbeidae) caught from Cross River at Obubra were studied. The seasonalized von Bertalanffy growth equation fitted to the length frequency data gave the following parameters: Loo= 18.0cm TL,K=0.47yr-1 , C=0.4, WP=0.86 and t0= -0.389yr with Rn=0.56. The instantaneous total mortality coefficient estimated from the seasonalized length converted catch curve, was Z = 1.57yr-1 The instantaneous natural mortality coefficient was M = 1.28yr-1 while the instantaneous fishing mortality coefficient was F = 0.03yr-1 the estimated current exploitation rate was E = 0.19. The probability of capture of each size class showed that the length at first capture was Lc = 7. 82cm TL. The Beverton and Holt's relative yield per recruit and relative biomass per recruited predicted a maximum exploitation rate Emax =0.52. The stock is not over exploited since E<Emax The analysis of recruitment pattern shows the existence of two recruitment regimes.
Keywords: Stock Stock assessment, Parailia pellucida, Cross River, Nigeria