SOME BIOLOGICAL ASPECTS AND POPULATION DYNAMICS OF THE RIVER NILE FISH, LABEO NILOTICUS (FORSKAL,1775)

Document Type : Original Article

Authors

1 Department of Animal Production, Faculty of Agriculture, Cairo Univ.

2 Depariment 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.

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