Biological assessment of Oreochromis niloticus (Pisces: Cichlidae; Linne, 1958) in a tropical floodplain river

Biological assessment of Oreochromis niloticus was conducted monthly between January, 2004 and December, 2006 in 3 zones [(Zone I: upper Cross River (savanna wetlands) Zone II: middle Cross River(savanna/forest wetlands) and Zone III: lower Cross River (forest wetlands)] along 200 km length of the inland wetlands of Cross River, Nigeria. Major items in the diet of O. niloticus were algae and plant 38and 20.4% (Zone I), 21.7 and 18.0% (Zone II), 20.2 and 26.9% (Zone III), respectively. Diet breadth ranged from 0.820 - 0.913. Food richness and Gut Repletion Index were 12 and 100%, respectively. Sex ratio was 1: 1 (Zone1), 1:0.78 (Zone II) and 1: 0.89 (Zone III). Mean allometric coefficients (b) of the lengthweight relationship were 2.194 ± 0.215 (Zone I), 2.935 ± 0.333 (Zone II) and 3.03 ± 0.202 (Zone III).Fecundity varied from 70 eggs for fish (total length (TL) = 11.00cm and weight (W) = 37.9 g) to 502 eggs (TL = 25.8cm and W = 198.8g) in Zone I, 60 eggs (TL = 13.3cm and W = 19.8g) to 709 egg (TL = 26.5, W= 317.0) in Zone II and 110 eggs (TL = 13.7cm, W = 24.0g) to 811 eggs (TL = 22.8cm, W = 278.8g) in Zone III. Relationship exists between fecundity and body size. Mean condition index ranged from 0.770 ± 0.128 minimum for males at Zone I to 1.188 ± 0.157 maximum also for males at Zone III. Therefore, male O. niloticus were in better condition than females and the forest wetlands of Cross River (Zone III) offered more favourable living conditions for the species than the savanna wetlands (Zone I and II)

Determination Of Optimum Stocking Density And Feeding Frequency For Heterobranchus longifilis (BURCHELL, 1822) Fingerlings In Aquarium Tanks

Fourteen day old fingerlings of Heterobranchus longifilis of average weight 0.85g in replicates of 6.50litres glass aquarium at 4.5, 9.0 and 18.0 fish/ litre fed ad libitum thrice daily at 10% biomass/day with 40% crude protein was used to determine the optimum density. The density 4.5 fish/litre produced the highest average weight of 5.2g in 50 days. To assess the optimum feeding frequency, 15-day –old fingerling average weight 0.95g were replicated in 4.50litre glass aquaria at density 4.5fish/litre (density with the highest average growth rate) and fed at five different feeding regimes; 1meal/day, 3meals/day, 4meals/day. Feeding frequency of 8meals/day gave the highest average weight (6.5g) with significant difference (

Application of a Stochastic Frontier Production Function to Measurement and Comparision of Technical Efficiency of Mandarin Fish and Clown Fish Production in Lowlands Reservoirs, Ponds and Dams of Cross River State, Nigeria

This study compared technical efficiency of mandarin fish and clown fish production in Cross River State, Nigeria. Data were obtained from 240 respondents(120 mandarin fish farmers and 120 clown fish farmers were randomly selected from villages in the study area by means of structured and semi-structured questionnaire. Data collected were analyzed using descriptive statistics and stochastic frontier function that incorporated inefficiency effects were estimated using the Maximun Likelihood Estimate (MLE). The result showed that the sum of elasticity for mandarin fish and clown fish were found to be 1.36 and 1.25 respectively implies that both production systems were operated in inefficient stage(technically inefficient). The result also showed that fish farmers’ educational level, access to credit, farm size and feed positively influenced their levels of efficiency in mandarin fish and clown fish production systems in Cross River State. Extension agents should guide fish farmers on levels of inputs combination that would ensure efficient production of fish. Regular awareness campaign about new technologies in fish production should be embarked on by extension agents; this will enable fish farmers adopt new technologies in fish production. Extension agents should train fish farmers on improved production technique while banks should give loans to fish farmers and strictly monitor all her loan beneficiaries to ensure loan repayment. The study also recommend efficient policy formulation and implementation that will encourage fish farmers and unemployed youth in Cross River State to joint fish producers cooperative(s) to enable them obtain loans at low interest rate from banks to increase their capital base for higher output

Fish Culture Technologies in Cross River State, Nigeria

Aquaculture has become an important sector in Nigerian economy and is considered a possible means of bridging the gap between the supply and demand for fish whose wild stock is fast declining, especially in the Cross River State of Nigeria. This study was carried out to assess the status, structure, operation and management options of fish culture systems and their significance in the economy of the region. Total number of 287 out of 346 fish culturists, were randomly selected across the three zones of the region. The results showed that the number of operational fishponds in the region was estimated to be 346 with 203 extensive and 105 semi-intensive and 36 intensive fish farms with majority of culturist operating at subsistence level. Common fish cultured in the three zones were Clarias gariepinus, Heterobranchus longifilis, Heteroclarias, Oreochromis niloticus, Clarias anguillaris and Hemichromis fasciatus. O. niloticus was most common in all zones accounting for 91.6 percent, Heteroclarias culture was practiced only in Zone C. Fish culture in earthen ponds was most common in Zone A and accounted for 40.9%, while most farms (33.3%) in Zone C raised their fish in concrete ponds. Flow through system was more adopted in Zone C constituting 51.9%, while stagnant ponds accounted for 74.2 and 56.8% in zones A and B, respectively. Integrated, monoculture and polyculture systems were observed in the study area, however, only polyculture was common in the three zones, while monoculture was absent (0.0%) in Zone C. Rainfall was the major source of water in Zone A(71.0%), while rivers/streams were the source of water for culturist in Zones B (52.3%) and C (53.3%). However, well water and borehole become the major source of water during the dry season. Most of the culturists were males of ages between 40 years and above with at least secondary school education and had experience in fish culture beyond eleven years. Fish farm activities was carried out mostly on part-time (61.8%) bases with poor fish supervision. Farmers with lowest average annual income (<N1,000,000) were found to be highest in Zone A (79.0%), while large- scale farmers formed a majority (85.7%) in Zone C. Personal savings was the most important source of financing farm operations among fish producers in Zone A(63.8%), while Bank loan constituted the highest (56.3%) source of finance in Zone C. Urgent steps must be taken to make credit available for expansion and sustainability to encourage new entrants especially the unemployed to start the enterprise. Keywords: Aquaculture, fish culture, ponds, rivers, rainfall, Nigeri

Toxicity Of Industrial Effluent To Oreochromis niloticus (Linnaeus, 1758) Fingerlings

The toxicity of industrial effluent from Odua Textile Mill, Ado-Ekiti on Oreochromis niloticus fingerlings was investigated. The fingerlings were exposed to increasing concentrations of the effluent in spring and pond water respectively. The mean lethal concentration (LC50) of the effluent in spring and pond water was 24.00mg/L and 31.2mg/L respectively. Mortality were significantly different (