Food, feeding ecology and condition index of the brackish river prawn Macrobrachium macrobrachion (Herklots, 1851) (Crustacea, Decapoda, Palaemonidae) in the Cross River Estuary, South-Eastern Nigeria

Investigations were carried out to study the food, feeding ecology and condition index of the brackish river prawn, Macrobrachium macrobrachion (HERKLOTS, 1851). One thousand, nine hundred and ninety-seven live specimens which comprised of individuals representing all size groups of the prawn were studied. The specimens were obtained from the commercial artisanal catches at Nsidung Beach along Calabar River (40301N and 80201E). Although algae formed the bulk of the diet of the prawn with 44.61% occurrence, other food items: detritus (24.30%), crustacean remains (23.14%), mud/sand particles (6.23%), fish bones and scales (2.14%) and small worms (0.21 %), were also consumed. The sub-adult and adult prawns respectively exhibited similar condition index of 0.98, while the youngs showed a condition index of 0.82. The significance of the similarities in condition indices between the sub-adult prawns and the varied condition indices among the young, sub-adult and adult prawns in addition to the exhibition of an overlapping feeding ecology by the prawn is discussed