Publisher: Bachudo Science Co. Ltd

The Reproductive Characteristics of Mudskipper Periophthalmus Barbarus (LINNAEUS 1760) (TELEOSTEI, GOBIIDAE) In The Estuarine Swamps of The Imo River, Nigeria

Lawrence Etim, F. N. Olele, Mfon T. Udo, Iniobong Iko Brownson
KEYWORDS: Reproduction, Mudskipper, Imo River, Nigeria

ABSTRACT:

Between December 2007 and September 2008, aspects of the reproductive characteristics of the mudskipper Periophtalmus barbarus were studied using samples (n = 1802) obtained from the Imo River estuary.  The overall sex ratio was not different from unity but analysis of ontogenic variation showed that males dominated in 5, 8, 10 and 11 cm total length size classes, while females were preponderant in the 6, 7 and 9 cm total length size class.  The number of males was not higher than the number of females during the dry and wet seasons.  The smallest mudskipper with incipient gonad was 8.0 cm total length.  The median size at maturity was 8.9 cm total length.  From the patterns of monthly variation in mean gonado6somatic index (GSI), it was concluded that the species breeds year6 round, with at least, one major peak (August to December) and one minor peak (May) in a year.  Length6weight allometric relationship for pooled data was W = 17.8 L2.60 with a dry season b value of 2.64 and a wet season b value of 2.55.  The monthly variation in mean hepatosomatic index (HSI) showed that the pattern of variation in mean HSI was a reverse of that of the mean GSI. The implication of this is that the species draws down on the energy reserves in the liver for the recrudescence of the gonad. A trade6off was apparent in the body’s use of resources for gonadal recrudescence.  Consequently when the mean hepatosomanic index was low, mean gonad somatic index was high. A major peak of GSI occurred from August to December while a minor peak occurred in May.  


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