AGE, GROWTH AND MORTALITY OF Bagrus bayad (FORSSKALL, 1775) FROM INLAND WATERS OF KEBBI STATE, NIGERIA

The fish of Bagridae are generally referred to as naked catfish. The Bagridae family has 30 genera and 210 species, which include; Auchenoglanis occidentalis, Chrysichthys nigrodigitatus, Clarotes lateceps, Bagrus docmac, and Oreochromis niloticus. This study was aimed at providing information and estimating age, growth mortality, and rate of exploitation of B. bayad to assess stock status as there is presently no data available on their population dynamics from inland waters of Kebbi state. The information supplied could be helpful for fishery resource planning, conservation, preservation and management of this specie.

Age, growth, mortality and rate of exploitation of Bagrus bayad from Kebbi State inland waters were examined from January to December 2017. Monthly frequency data was assessed using FiSAT software to estimate population parameters, including asymptotic length (L ∝), growth coefficient (K) and recruitment pattern to determine stock status. Estimation of age was obtained by using Bhattacharya’s method that is incorporated in FiSAT. The average length of the Bagrus bayad was of 11.65 cm, and 16.89 cm (Table 1), At the end of the first and second years respectively, with an average growth rate/year of 4.56 cm. The predicted extreme length (Lmax) was found to be 45.03 cm Asymptotic length (L ) and growth coefficient (K) were 45.03 cm and 0.47 (yr-1), respectively. Total mortality (Z) by length-converted catch curve was estimated at 1.53 (yr-1), fishing mortality (F) was at 0.56 (yr-1), and natural mortality (M) was at 0.97 (yr-1). Level of exploitation (E) was 0.37. The pattern of recruitment was constant, with two significant peak pulses per year. The results of the exploitation rate (0.37yr-1) indicate that B. Bayad was under fished by 26 percent. This implies that the fish stocks in the study area are underexploited as a subsistence fishery.