SOME BIOLOGICAL ASPECTS AND POPULATION DYNAMICS OF THE RIVER NILE FISH, LABEO NILOTICUS (FORSKAL,1775) | ||
| Egyptian Journal of Aquatic Biology and Fisheries | ||
| Article 19, Volume 1, Issue 2, June 1997, Pages 325-345 | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejabf.1997.3393 | ||
| Authors | ||
| Adel Tharwat1; El-Sayd Fikri El-Dawi2 | ||
| 1Department of Animal Production, Faculty of Agriculture, Cairo Univ. | ||
| 2Depariment of Zoology, Faculty of Science, Ain Shams Univ. | ||
| Abstract | ||
| abeo niloticus, is one of many fishes that decreased or nearly disappeared in catch, from different areas of the River Nile, especially in Cairo and Giza. In the present study age, growth, reproductive biology and population dynamics of this species from the River Nile at Cairo and Giza were studied. The study revealed that the total mortality rate was 81% yearly, whereas, the estimated values for natural and fishing mortality coefficients were 0.58 and 1.08, respectively. Also, the exploitation rate of the fish stock was 0.65. Moreover, the longevity of L. niloticus in the catch was three years only. Average fish size (26 cm, total length and 145 g total weight) was smaller than the size and weight at the first sexual maturity (31 cm. total length and 248 g. total weight). The aforementioned results indicate that the low density in the population of Labeo niloticus is attributed to over fishing. Thus, it is recommended to prevent catching the fish size less than 31 cm T.L. or 248 g T.W. This is to give at least one time for the mature fish to spawn and to recruit the fish stock. | ||
| Keywords | ||
| age and growth; reproductive cycles; fish population dynamics; Labeo niloticus | ||
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