GROWTH AND REPRODUCTION OF THE SHRIMP POPULATION IN A LAGOON SYSTEM IN SOUTHERN BENIN (WEST AFRICA)

What is it about?

The aim of this work was to characterize the growth and reproduction dynamics of shrimp in the Lac Nokoué-Chenal de Cotonou complex. The results of one year’s sampling from five stations (North, South, East, Central and West) of the lagoon complex revealed that that linear growth in size in Lake Nokoué is decreasing over time in Macrobrachium macrobrachion, but positive in Penaeus notialis (the most representatived species of the genus Penaeus). Size-weight relationships indicate that the lowest growth coefficient (b = 1.56) is obtained in immature males of Macrobrachium felicinum, while the highest growth coefficient (b = 3.39) is obtained in mature females of Macrobrachium vollenhovenii, with an average of 2.84 for all shrimp species sexes considered. The χ2 test indicated that only the species Macrobrachium vollenhovenii has a significant sexual imbalance in favor of females in Lake Nokoué. However, the same test indicates that there is not enough evidence to differentiate the sizes of first sexual maturation in Macrobrachium vollenhovenii and Macrobrachium macrobrachion species. This work revealed that Penaeus monodon was the only species to show better positive growth within all its groups in Lake Nokoué exposed to anthropogenic effects. Our results indicate a progressive growth in size of the Penaeus notialis species in Lake Nokoué between the beginning and end of the saline intrusion (which confirms the life cycle of the species presented).

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