Effects Of Effluents From Gbalegbe River, Delta State, Nigeria On The Breeding Performance Of Clarias Gariepinus (Burchell, 1822).
Authors:   Department of Fisheries and Aquaculture Management Faculty of Marine Environmental Management, Nigeria Maritime University Okorenkoko, Warri South, Delta State, Nigeria & Department of Aquaculture and Fisheries Management Faculty of Renewable Natural Resources University of Ibadan, Ibadan, Nigeria., Ewutanure S.J. , Olaifa F.E. 
Published: January 2022

A study was carried out on Gbalegbe River water to assess the impact of anthropogenic activities on the breeding and growth performance of Clarias gariepinus using effluent directly from the point source. The experiment was set – up in a complete randomised design with 5 treatments (TR1, TR2, TR3, TR4 and TR5) and 2 replicates for 12 weeks. Concentrations of 100 %, 75 %, 50 %, 25 % and 0 % were prepared according to standard methods. Borehole water was used as control (0 %) after exposure for 72 hours. Two matured gravid and one male C. gariepinus of 4.5 kg-1 each were purchased from a reputable fish farm in Delta State, Nigeria and acclimatised in the laboratory for 2 weeks. The two gravid C. gariepinus were then induced with Ovaprim hormone at 0.5 mg. kg-1. Stripping was done after a latency period of 9 hours. The eggs were then fertilized with the milt obtained from the male fish at a temperature of 24.5 oC. About 1.0 g of eggs was incubated in ten aquaria of water holding capacity of 20 litres each. Hatching started and stopped at 20 and 28 hours, respectively. Fish were fed ad-libitum for 84 days while unhatched eggs, unconsumed feed and dead fry were carefully siphoned. Parameters analysed were water quality: Temperature – oC, Dissolved Oxygen, DO – mg.L-1); Growth (% Hatchability and Feed Conversion Ratio – FCR); Total Petroleum Hydrocarbon (TPH) in water (mg.L-1) and Heavy Metals (HM) – (Copper, Chromium – mg.L-1) in fish (mg.kg-1), Packed Cell Volume (% PCV) and Alkaline Phosphatase (ALP – IU.L-1). The duration of the experiment was 12 weeks. Data obtained were subjected to inferential and descriptive statistics at α0.05. Highest (27.50±0.55) and least (24.53±4.35) Temperature; DO (4.53±0.15, 3.01±1.65); Hatchability 71.13±0.37, 39.74±2.06); FCR (1.19±0.43, 3.92±0.08) were obtained in TRT5 and TR1, respectively. Highest (0.67±0.03) and least (0.09±0.02) TPH in: water occurred in TRT1 and TRT4; C. gariepinus (5.01±0.66, 0.18±0.07) in TRT1 and TRT4, respectively. Highest (0.66±0.53) and least (0.09±0.00) HM (Chromium and Nickel) in water where recorded in TRT1 and TRT2. HM – Copper and Manganese in C. gariepinus ranged from 0.04±0.01 to 0.64±0.13 in TRT4 and TRT1. Highest (49.37±3.07) and least (20.62±3.37) PCV occurred in TRT5 and TRT1; ALP (32.22±3.18, 6.99±4.26) in TRT1 and TRT5, respectively. The sharp variation in FCR, HM and ALP showed that the increased anthropogenic effluents in Gbalegbe River could threaten the positive breeding performance of C. gariepinus. It is therefore recommended that consistent and adequate monitoring of Gbalegbe River should be encouraged to guarantee sustainable fisheries abundance. Keywords: Anthropogenic Activities, Fish Breeding, Feed Conversion Ratio, Heavy Metals, Packed Cell Volume.