Recruitment pattern and abundance of the black tiger shrimp in Andoni River System, Niger Delta region of Nigeria

Abstract

The investigation on the recruitment pattern and catch per unit effort of the black tiger shrimp(Penaeus monodon) was conducted over the period of twelve months in Andoni River System, Niger Delta region of Nigeria. Total weight, length of sampled P. monodon, number of fishers, fishing duration and temperature were sampled monthly. Total weight of P. monodon landed, number of fishers and fishing duration was used to determine catch per unit effort in kg/man/hr while United Nations Food and Agricultural Organization fish stock assessment tools II (Fisat II) software was used to analyze recruitment pattern using the length frequency data of the stock. Recruitment pattern was continuous and higher during the rainy season with a peak in June. Catch per unit effort was lowest (46.09 kg/man/hr) in January and highest (78.11 kg/man/hr) in September. Mean temperature ranged from 27±0.32ᴼC to 31±0.89ᴼC which was suitable for the stock. A positive moderate correlation existed between recruitment and catch per unit effort (r = 0.50) while a positive weak correlation occurred between recruitment and temperature (r = 0.21). The study concluded that a rise in the recruitment of P.monodon suggests a rise in catch per unit effort and that temperature was not the only factor necessary for recruitment.