Effect of runoff from alluvial soil on fish diversity from Oko mayon water body Okun owa, Ogun State

Résumé

In this study, the effect of runoff from alluvial soil on fish diversity in river Oko-Mayon along Sagamu express road between February to August, 2017 was assessed. Fish samples from fishermen using assorted gears were identified to the species level. Soil sample was collected using soil auger from the bank of the river to determine the alluvial level. Water quality parameters were also determined. The results showed that 311 fish species sampled had 13 fin fish species from 12 families. Mochokidae family had the highest composition(21.21%) while the most abundant fish species in the river was Synodontis violacea. The values should be for Physical and Chemical parameter of soil assessed included temperature (27.84±0.90-27.98±0.084)?C, %, sand (75.28±3.85-78.48±9.65), % silt (7.68±1.67- 9.60±3.17), % clay (11.92±2.54-17.04±2.83), pH (13.30±0.09-13.37±0.10), Conductivity (84.20±19.77-122.00±25.17), Total dissolved solid (42.20±9.81-60.60±12.34) mg/L, organic carbon (0.61±0.60-0.70±0.45), nitrates (0.11±0.01-0.14±0.02) mg/l, Phosphate (34.16±3.06-42.56±1.50) mg/l, with significant difference (p<0.05) except in percentage of sand and silt. The values for physical and chemical parameter of water included temperature (24.95±0.21-28.65±0.21)?C, Transparency (20.50±0.71-22.50±0.71)cm, Electrical conductivity (167.50±0.71-177.50±0.71)? , pH (6.65±0.07-8.74±0.06), Total dissolved solid (83.50±0.71-88.25±0.35)mg/l, Phosphates (0.18±0.01-2.08±0.01)mg/l, Nitrate (0.02±0.00-0.064±0.01) mg/l with significant difference (p<0.05) except in transparency. Strong correlation was obtained between total fish catch and total nitrogen in water (1.000), Available phosphorus in soil and total fish catch (0.999), electric conductivity and % silt of soil (0.999), total dissolved solid and % silt of soil (0.998), total dissolved solid and electric conductivity of soil (1.000), available phosphorus and temperature (0.999), available phosphorus and total nitrogen (0.998) of soil and water at (p<0.05). The river contributes much to the inland fishery of the State as a result of its high composition of fish species which is an evidence of its high productivity.