Alterations in the levels of ions in muscle and liver of African catfish, Clarias gariepinus exposed to paraquat dichloride.

Abstract: The electrolyte levels (Sodium and Potassium) were determined in the liver and muscle of African catfish, Clarias gariepinus exposed to various sub-lethal concentrations of paraquat dichloride (0.01, 0.02, 0.03, 0.04 and 0.05 mg/L). Sodium (Na + ) decreased significantly (p<0.05) from the control as the concentration of paraquat increased, with the exception of the first experimental group (with lowest concentration of paraquat), where the liver Na + level was significantly (p<0.05) higher than the control, while the muscle Na + level did not vary significantly (p>0.05) from the control. Thus, the variation of Na + tended to depend on the concentration of paraquat. On the other hand, potassium (K + ) did not show any district pattern, with significantly (p<0.05) higher values at the various concentrations of paraquat than the control. However, there was no significant (p>0.05) difference between the K + levels in both the liver and muscle of the control and those of the fifth experimental group, with the highest concentration of paraquat treatment. This pattern of variation exhibited by Na + and K + suggested that the fish adjusted effectively to stress within the limits of toxicant exposure used in this study

The Zooplankton Species Composition and Abundance in Sombreiro River, Niger Delta, Nigeria

Abstract: The zooplankton species composition and abundance in Sombreiro River, in the Niger Delta of Nigeria was studied for a period of two years (August, 2007-July, 2009), using filtration technique. 25 :m mesh size plankton net was towed from a dugout boat at about 5-105 -1 for about a minute. The net content was washed out into a wide mouth plastic container and preserved in 10% formalin solution after proper labeling. A total of seventeen (17) species belonging to six (6) taxonomic groups were recorded from Sombreiro River. The groups Cladocera and Copepoda were represented by five species each consisting of 29.4% by composition. This was followed by three species of Protozoa (17.6%), two species of Rotifera (11.8%), Decapod crustacean (5.9%) and Euphasiacea (5.9%), one specie each. Copepoda was the highest, 46.5%. This was followed by Cladocera (23.3%). The others were Protozoa (11.2%), Euphasiacea (9.6%), Rotifera (7.9%) and Decapod Crustacean (1.5%). The low zooplankton diversity observed in this study is common in tropical waters. The dominance of cladocera and copepoda in the study area is common to River Nun, in the Niger Delta and Schelde estuary in Belgium. Sombreiro River zooplankton abundance is higher than that of River Nun but lower than that of Imo River in the Niger Delta. These differences are attributed to duration of sampling and natural conditions of the water bodies. The zooplankton abundance was well distributed in the stations except Mysis sp. (Decapod Crustacean) which showed spatial discontinuity in abundance

Effect of Diazinon on Acid and Alkaline Phosphatase Activities in Plasma and Organs of Clarias gariepinus

Abstract: The aim of this study was to determine the effect of the pesticide, diazinon, on phosphatases in the plasma and organs on Clarias gariepinus. Adult Clarias gariepinus were exposed in four replicates to varying sublethal concentrations diazinon (ranging from 1.00 to 10.0 mg/L) in 30-day semi-static bioassays. Alkaline phoshatase (ALP) and acid phosphate (ACP) were determined in plasma and other organs (gastrointestinal tract -GIT, kidney, muscle, gill and liver) of the fish after the experimental exposures. Dizinon did not cause any statistically significant difference on plasma ALP over the concentrations tested (p>0.05), but ACP showed significantly higher mean value at 10 mg/L compared to the control. ALP and ACP values in all the organs (GIT, intestinal tract, kidney, muscle, gill, liver) decreased with increasing concentration of diazion. This indicates an evidence of inhibition of these enzymes in the organs by the toxicant, and therefore alteration of biochemical processes in C. gariepinus which can be used as bio-indicators of the effects of diazinon in the Niger Delta environment

Effects of Water Pollution on the Condition Factor, Mortality, Exploitation Ratio and Catch per Unit Effort of Lagocephalus laevigatus in Koluama Area, Niger Delta Area, Nigeria

Abstract: Effects of water pollution on the condition factor, mortality, exploitation ratio and catch per unit effort of Lagocephalus laevigatus in Koluama Area, Niger Delta Area, Nigeria was investigated from April 2012 to May 2012; following an oil blow out in the area. To show the impact of the spill on the environment, catch rates are seasonally dependent and vary between 15-120 kg/day. About 120 wooden canoes were sighted in the communities studied. The canoes are basically in two categories namely, small sized boats of less than 5 m length and mediumsized ones ranging between 5 and 7 m long. There was no temporal variation in the condition of the fish with condition index value ranging from 0.86-1.00 and condition factor value of 0.98. The K value of 0.98 estimated from this study shows that Lagocephalus laevigatus from the study area was in extremely poor condition. Total mortality (Z) value was 1.5 yrG1. Natural Mortality (M) value was 0.97; Fishing mortality (F) value was 0.52. Value for the rate of exploitation was 0.35 with corresponding percentage value of 35%. The result shows that Lagocephalus laevigatus with an exploitation rate of 0.35 is below the optimal value for sustainable yield, for the exploitation of the fishery. These populations therefore stand the risk of under exploitation if urgent measures are not taken to develop the fishery