Studies on some reproductive aspects of Pseudotolithus elongatus in Cross River estuary, Nigeria
S.B. Ekanem, M.N. Achima, M.M: Ekere

To determine the spawning time of Pseudotolithus elongatus in the Cross River estuary, ovarian development, egg diameter, gonadosomatic index (GSI) and hepatosomatic index (HSI) of the female fish were studied from January to December 1998. All ovary developmental stages, including the spawning stage, were present every month, which indicated year-round spawning. High mean values of GSI and egg diameter in December-March and July-September indicated these as the two peak spawning periods for the species. The egg diameter ranged from 1 µm to 590 µm. The highest number of eggs found in an individual fish was 808911. Absolute fecundity of the species in The Cross River estuary can be calculated in relation to standard length using the formula F = 17557SL0.768 or F = 45532W0.277 in relation to weight. There were evidences to suggest that the species is an asynchronous partial spawner. The stock might be effectively conserved by the imposition of a closed fishing season during the two peak spawning periods.

Keywords: Pseudotolithus elongatus, spawning, Cross River estuary.
Contents of this volume Sci. Mar. 68(2) : 265-271 Back PDF
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