ABSTRACT:A frame survey of fishing communities was carried out, employing the complete census technique, to assess the artisanal fisheries characteristics of the fresh water reaches of lower nun river for a period of two year, Eleven Community lie along the stretch of the study area. The total number of 4718 fishers with 1645 canoe units employing various fishing gear resulted to a fishers density of 3 fishers per canoe unit. A total of 29 fin fish families were recorded. Seasonally occurring fresh water crustacean. Attaya gaboneensis and palacemon paucidens were present. Etheria elliptica, an oyster was also present. A specie of fresh water clam, Galacea Paradoxa from the family Donacidae was present. Trichechus senegelensis (Manattee) was occasionally captured by local hunter during the flood period. Hippopotamus amphibious (Hippopotamus) was reported from isolated places but they were rare. A specie of Otta, Lutra macullicolis was present. Three species of crocodiles, Crococdylus niloticus Crocodylus cataphractus (Alligator) and Osteolaemus tetraspsis were also present. The Nile monitor, Veramus niloticus and the aquatic snake, Anoscopus sp. And three species of water turtle, Kimxy erosa, Pelumedusa sp and Peliosus sp were also present. The commonest fishing method employed was local fishponds (50.8%) and the least was gill nets (1.6%). Drift net caught the highest fish (8.01kg) per gear, while local fishponds was the least 0.25 kg. The annual catch per canoe was recorded for local fishponds (167. 84kg), while the lowest was assorted traps (14.7kg). Drift not recorded the highest annual for local fishponds. The mean biomass of 25.04 of fish catch of 20.2kg per fisher and the lowest value (4.53kg) was recorded per boat, total catch of 37903. 6kg, annual producing estimate of 434.81 tonnes, standing struck of 2.27 km -2 and of twenty two million, seven hundred and forty two thousand one hundred and sixty naira (N22742160) was estimated. The reduced annual income per fisher in the study was four thousand, eight hundred and twenty naira, thirty kobo. There is therefore the, urgent need for effective management of the Nun river fisheries, to improve on the living standard of the people. @JASEM

Acute toxicity of xylene on an African catfish (Clarias gariepinus) was carried out. A total of 210 catfish C. gariepinus juveniles with mean length 15.20±2.3cm, and mean weight of 10.23±2.6g were obtained from the University of Port Harcourt Demonstration Farm. The test was determined for 96hour median lethal concentration using concentrations of 250ml/l, 200ml/l, 150ml/l, 100ml/l, 50ml/l, 25ml/l and 0.0ml/l (control) which gave a LC50 value of 63.965ml/l with upper and lower confidence limits at 106.53 ml/l and 37.82ml/l respectively. The median lethal time LT50 recorded was 55.7 hours. There was a strong correlation between (%) mortality in Probits and the Log10 Dose (R²=0.9772). There was statistical significance (P>0.05) in the number of mortality observed in the six concentrations from 24 hours to 96 hours of exposure and high percentage mortalities were recorded as the concentration of the toxicant increased. No mortalities were recorded in the control. The cumulative mortality recorded after exposure of C. gariepinus to xylene was time dependent. Based on this the high percentage mortalities of the fish species it is therefore recommended that the use of this chemical be minimized and proper contingency plans be carried out before discharging this toxicants into the aquatic environment. Waste from this chemical and spill incidences should be detoxified to a less toxic level before disposing into the aquatic environment. The results obtained may provide valuable information for formulation of environmental policies and serve as a model for bio-monitoring of the aquatic environment.

Sampling was done in six sampling stations for one year (August, 2014-July, 2015) to investigate the impacts of makeshift oil refineries on the macro-invertebrates of the Nun River estuary in the Niger Delta region of Nigeria after over 3 years of chronic pollution of this estuary by the makeshift refinery activities. There was also a massive destruction of the benthic and mangrove associated macrofauna of the Nun River estuary and its tributaries. 18 species of benthic macro-invertebrates distributed among 15 genera and 9 families were recorded during the study. A total of 2, 942 individual organisms were collected in which 41 belonged to the Class Polycheata, 684 belonged to the Class Decapoda (subphylum crustacea), and 2, 217 belonged to the Class Gastropoda. The class Gastropoda, made up of 1 family and 2 species had the highest percentage composition (75.36%) and are the most dominant species of the area, followed by the class Decapoda (23.25%), and Class Polychaeta (1.39%), respectively. About 12 organisms (which were present during the baseline study) were absent during the current study. The biodiversity of the estuary is low. The alteration of the physico-chemical parameters as well as the direct contact with the spilled crude oils which resulted from the makeshift oil refinery activities is responsible for the massive destruction of the macro zoobenthos in the area.

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