A study of abundance of planktonic organisms in Lekan-Are Lake, Ogun State, Nigeria

A study of the plankton abundance in the shore, surface and bottom of Lake Lekan-Are Abeokuta, Ogun State, Nigeria was carried out between January 2007 and August 2008 at three stations along the entire stretch of the lake. The numerical abundance of the plankton in this lake was investigated. There were marked seasonal variations in the zooplankton and phytoplankton of the lake. Four major groups of phytoplankton were identified Baccilariophyceae (diatoms), Chlorophyceae (green algae) and Cyanophyceae (blue green). The green algae dominated the phytoplankton constituting 63.3% in the surface and 54.8% in the bottom zone of the lake. The phytoplankton density was at its peak in sunny months of January to early June that coincided with the period of high temperature. The three major groups of zooplankton observed in the lake were Cladocera, Copepoda and Rotifera. The Copepoda dominated the three habitats 83.37% (shore), 82.73% (surface) and 80.26% (bottom). Copepoda also dominated at the three stations of the lake. The  seasonality of zooplankton followed a similar pattern with that of the phytoplankton reaching a peak between February and May.Keywords: Numerical abundance, plankton Lekan Area, Nigeri

Public Perception of Potable Water Supply in Abeokuta South west, Nigeria

The perception of residents towards the supply of potable water to  Abeokuta was assessed with the aid of questionnaire. Well-structured interviewer administered questionnaire were distributed across the city through the stratified random sampling method using the network  distribution map obtained from the Ogun State Water Corporation as guide. Sixty – eight per cent of the respondents attested that the quality of the water supplied was unsatisfactory while 36% agreed that they had contacted water related diseases as a result of the consumption of drinking water obtained from public taps. Sixty – five per cent of the respondents use less than 120 litres of water daily, while 77% attested that the water supplied did not meet their daily demand. Only 39% of the respondents who relied on water from alternative sources subjected the water to  treatment before usage. It was advised that issues of inadequate water supply and coverage area be addressed speedily and residents should subject water obtained from alternative sources to treatment. The  Corporation was also advised to pay attention to the state of infrastructureacross the distribution network.KEYWORDS: questionnaire, quality, potable water, distribution network

Effects of oven and air dried pituitary hormone on the ovulative capacity of gravid Clarias gariepinus

Effects of oven and air-dried pituitary hormone on the ovulative capacity of gravid Clarias gariepinus was carried out in a commercial fish hatchery farm between the months of October and November, 2008. Nine female gravid Clarias gariepinus weighing about 1kg each was injected with oven dried, air dried and wet pituitary hormone (wet pituitary hormone acted as the control). Injected brooders underwent indoor temperature conditions varied from 240C -270C, ovulated eggs were manually expressed and incubated. Differences occurred among the means of the treatment with respect to weight of the egg per treatment and rate of hatchability among the samples. There is nosignificant difference between oven dried pituitary (Treatment 2) and (Treatment 1) which is the control except in the number of eggs. The mean difference percentage hatching and weight of ovulated egg is significant at (p < 0.05)

Efficacy of some synthetic antibiotics on Streptococcus pneumoniae and Proteus mirabilis isolated from fish tanks

Effects of some synthetic antibiotics on Streptococcus pnemoniae and Proteus mirabilis isolated from cultured Clarias gariepinus, an important food fish raised in a concrete tank was carried out to ascertain their remedies on mortalities of the Clarias gariepinus adult fish. Streptococcus pnemoniae and Proteus mirabilis were isolated from the gill and skin of diseased fish and water samples and identified by standard microbiological methods.The bacteria isolates were tested for sensitivity on ten (10) antibiotics namely Amoxycillin, Gentamicin, Nitrofurantoin, Erythromycine, Augmentin, Tetracycline, Naladoxic aci d, Cotrimoxazole, Cloxacillin and Ofloxacin. These organisms reacted differently to the different antibiotics that were used - Ofloxacine, Gentamycin and Erythromycine had highest zones of inhibition of 26mm and 26mm, 24mm and 19mm, 16mm and 17mm respectively around Streptococcus pnemoniae and Proteus mirabilis, but Naladoxic acid, Augmentin, Cloxacillin and Amoxycillin had no inhibition zones around both organisms. It is therefore recommended that Ofloxacine, Gentamycin and Erythromycine can be used to combat S. pnemoniae and P. mirabilis diseases in fish farms because of their high antibacterial potentials against the test organisms.Keywords: Streptococcus pnemoniae, Proteus mirabilis, Clarias gariepinus, Syntheticantibiotic

Heamatological Changes in Clarias Gariepinus Exposed to Cypermethrin

The acute toxicity of cypermethrin, an insecticide, to juvenile African catfish, Clarias gariepinus was investigated with emphasis on haematological effects. Juvenile Clarias gariepinus (Burchell 1822) were exposed to 0, 1.9, 4.1, 9, 21, and 45 mg L-1 cypermethrin. The lethal concentration (LC50) of cypermethrin was 63 &#956;g L-1 at 96 hours of exposure. Mean mortality percentages were 0, 0, 70, 90, 100, and 100, at the concentrations 0, 1.9, 4.1, 9, 21 and 45 mg L-1, respectively. Respiratory stress, erratic swimming, and instant death were observed for fish exposed from 4.1 &#956;g L-1 and above. Cypermethrin is highly toxic to juvenile fish. These changes occurred predominantly in the 96h exposure at the concentration 9 &#956;g L-1. Cypermethin concentration corresponding to the 96h LC50 value for juvenile C. gariepinus was used to study the effects of cypermethin exposures in inducing histopathological changes of liver and kidney. In the liver, there was vacuolation of hepatocytes and necrosis. In kidney there was exfoliation and swollen with pyknotic nuclei. These changes occurred predominantly in the 96h exposure. There was a progressive decrease in heamatological parameters of fish as the concentration of the toxicant increased. Also, haematological indices indicated that the fish became hyperglycaemic and hypoproteinaemic and the severity of this condition was directly proportional to the cypermethrin concentration. Investigation on white blood cells (WBC), red blood cells (RBC), packed cell volume (PCV), indicate low immune system of the fish in fighting diseases