Age And Growth Of An Ecotype Cichlid “Wesafu” In Epe Lagoon, Lagos, Nigeria

A sample of 150 specimens of “Wesafu” in the size range of 78mm and 414mm were collected from Epe Lagoon. The period of collection spanned August to November 2003 and April to Ma y 2004 for age and growth pattern determination of this Ecotype Cichlid of Epe Lagoon. 900 scales were examined and another 232 rejected/discarded because they were regenerated or irregular. Growth rings were counted and scale radii measured. The study showed a mean range of observed lengths to be 181±12.5; 265 ± 11.6; 305 ± 1.6 and 337 ± 3.4 for the successive years of growth. The most rapid growth in length occurred during the first year in life [181mm, (+1yr.)] thereafter decrease to only 32mm in the fourth year (+4yr.). The T-test suggests that there was no significant difference between mean back-calculated body length of male and female samples for age 1+ to 3+. However, in the age group 4+, male specimens were significantly larger than the female. The fact that the fish is highly demanded and commands premium price may result in over exploitation. This explain why only 5 of the 150 specimens were of the age 4+, representing only 3.33% of total specimens which raises serious conservation question and the need for domestication and aquaculture of this highly valued fish in Lagos, Nigeria. Keywords: Age and Growth, Ecotype Cichlid, Epe-Lagoon, NigeriaGlobal Journal of Agricultural Sciences Vol. 7 (1) 2008: pp. 105-10

The use of cold shock in inducing triploidy in African mud catfish (Clarias gariepinus)

study was conducted to induce triploidy in African mud catfish Clarias gariepinus using cold shock. The fertilized eggs were exposed at one temperature regime of 0°C with varied shock treatments of 0, 15, 25 and 30 min. Some 3 min after fertilization, the success of triploidy was determined by the presence or absence of bent trunk in the fry as reported by (Aluko et al., 1997). The shock duration of 25 min at 0°C gave the best result of 55% hatch with survival at the end of the exposure regime of 43.5%. Shock exposure of 30 min gave 30% hatch while 15 and 20 min exposure were poor at 15% hatch

Performance and carcass characteristics of finishing pigs fed raw or extruded full-fat soya beans rations in humid lowland tropics

No Abstract