Freshwater Fish Diversity of a Tropical Rainforest River in Southeast Nigeria

Fish samples were collected at three stations twice per month from January to December 2013 with the help of local fishers using hook and line, gill net, cast net, bagnet and local traps for ecological studies of important fish species and resource management issues of Oramiri-Ukwa River, southeast Nigeria. An estimate of 25 fish species, 15 genera, 21 families and six orders were obtained. Ecological indices indicate a polydiverse community and no single species exhibited true dominance (? 50%). Paired group cluster analysis establishes Tilapia zilli and Hemichromis fasciatus as the focal species and identifies the associated species combinations that characterize spatial variability and account for the biodiversity resources and structure of the artisanal fishery. Other important species include Tilapia mariae>Synodontis nigrita while Polypterus senegalus>Parachanna africana and Shilbe mystus were the least in number. Monospecific and rare fish species of ecological and conservation significance identified include Ctenopoma kingsleyae, Clarias gariepinus as well as Erpetoichthys calabaricus and Pantodon buchholzi derived from interconnections with other African rivers. This study presents lower fish diversity compared to earlier reports. This difference may be linked to increased human activities and fluctuating biotic and abiotic factors of the ecosystem, among others. Keywords: Abundance, biodiversity, conservation, rare specie

Optimum range of pH for hatching of incubated eggs of Clarias gariepinus (Siluroidei: Pisces)

No Abstract. Animal Production Research Avancees Vol. 3 (2) 2007: pp. 158-16

Effect of pH and temperature interactions on the hatching rate of African catfish eggs

No Abstract. Animal Production Research Avancees Vol. 3 (2) 2007: pp.171-17

Tropentag 2011 Development on the margin The Parasites of Cultured and Feral Nile Tilapia (Oreochromis niloticus) in Umudike

Abstract Fifty eight specimens of Nile tilapia (Oreochromis niloticus) were collected between the months of August and November with the use of siene net from the culture ponds of Michael Okpara University of Agriculture, Umudike and the water reservoir of National Root Crops Research Institute, Umudike impounded from Ohii Stream. Vital morphometric data of the specimens were recorded with the aid of calibrated metre rule while visual examination of the external part of the fish specimens were carried out immediately with the naked eye and hand lens for ectoparasites. This was followed by dissecting the specimens to obtain the internal organs which were properly labeled and preserved in 4% formalin for further examination. The preserved organs were subsequently sliced separately into piece, mixed with water and examined under stereo microscope for endoparasites. The recovered parasites were placed on covered slides and examined under the light microscope. The parasites obtained from each specimen were then properly counted and classified. No significant difference was observed in the level of parasitic infection between the pond cultured (89.65 %) and the wild (93.10 %) O. niloticus. This may be because both the ponds and reservoir have Ohii Stream as source of water. Trematodes, Cestodes and Copepods were the major parasites found on O. niloticus from both habitats. Trematodes and Cestodes constituted 48.8% and 41.38% respectively for cultured O. niloticus, while the feral O. niloticus had 13.8%, 17.2% and 62.0% Trematodes, Copepods and Cestodes respectively. The Cestodes were found in the intestine of O. niloticus while the Trenatodes and Copepods were found on the gills. Among the size groups 11-15 cm in the culture ponds had the highest occurrence of Trematodes (24.14%) while 6-10 cm class of feral habitat had the highest occurrence of Cestodes (58.62%). Similarly 6-10 cm class of reservoir O. niloticus had the highest (10.34%) infection of Copepods