African Journals Online
JOURNAL OF AQUATIC SCIENCES

Volume 14, April 1999

ACUTE TOXICITY AND GILL MORPHOLOGY OF OREOCHROMIS NILOTICUS (TREWAVAS) EXPOSED TO ROGOR (R)

P. A. ANNUNE AND S. U. AJIKE
Department of Biological Sciences, Ahmadu Bello University, Zaria, Nigeria
*Present Address: Department of Biological Sciences, Benue State University, Makurdi, Nigeria

ABSTRACT
The acute toxicity of Rogor(R) was determined for juvenile bony fish, Oreochromis niloticus in 96-h static bioassays. The fish treated with Rogor(R) showed abnormal behaviour characterised by restlessness, uncoordinated movements, loss of equilibrium, air gulping, loss of buoyancy, periods of quiescence and death. The 96-h LC50 of Rogor(R) for O. niloticus was 0.018 (0.015.022) ml/1. Rogor(R) treatment caused epithelial detachment in the primary and secondary lamellae. It was suggested that osmoregulatory and respiratory incapacitation through mucus accumulation and histologic damage are the major causes of fish mortality following Rogor(R) exposure.

Key Words: Rogor, toxicity, gill, morphology, Oreochromis niloticus


FERTILIZATION OF EARTH PONDS I: EFFECTS ON PHYSICO-CHEMICAL CHARACTERISTICS AND ETHROPHICATION OF POND WATER AND SOIL

J. W. WADE* AND H. P. STIRLING
Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland U.K.
Present address: Department of Zoology, University of Jos, Jos, Nigeria.

ABSTRACT
Various biomanipulation strategies, using inorganic and organic fertilizer to improve oligotrophic conditions were carried out in earth ponds in Central Scotland U.K. over a period of one year. Replicate ponds were treated with low and high phosphorus (LP, HP) high phosphorus and nitrogen (HPN), low and high chicken manure (LC, HC) high chicken and cow manure (HCC) and tow untreated controls (CTRL). The effects of treatments on physio-chemical parameters of the pond water and soil suitable for trout culture was also evaluated along with primary production. There was generally remarkable improvement in eutrophic condition with respect to water and soil qualities. Water pH rose steadily from 7.0 - 7.5 at pre-manipulation state to 7.73 - 8.39 in the CTRL, LP and HPN in response to liming and fertilization. Soil pH was generally acidic in the range, 5.80 - 6.64 in both organic and inorganic fertilization. Differences in nutrient (ammonia, nitrate and phosphate) concentrations were consistent with fertilizer application. Nitrite showed an initial decline in CTRL, LP and HP, but there was an upsurge in HPN, which significantly varied (P < 0.05) with other treatments. High Biochemical oxygen demand (BOD) in HC treatment coincided with fall in dissolved oxygen (DO). The response pattern of primary production and chlorophyll - a (Chl-a) used as index of eutrophication significantly between treatments and periods (P <0.05). The significance of fertilizer application vis-à-vis water quality criteria are discussed in the light of contemporary in resource utilization and management, and an aquatic ecosystem undergoing transition from oligotrophic to eutrophic status.

Keyword: Fertilization, earth pond, water, soil and eutrophication.


FERTILIZATION OF EARTH PONDS II: EFFECTS ON PLANKTON COMMUNITIES

J. W. WADE AND H. P. STIRLING
Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, Scotland, U.K.
*Present address: Department of Zoology, University of Jos, Jos - Nigeria.

ABSTRACT
A study of the effects of slurry inorganic and organic of fertilizers on the production of phyto-and zooplankton in earth ponds was conducted in Central Scotland, U.K. over a period of one year. For the inorganic fertilization, replicate ponds were treated with low and high phosphorus (LP, HP), high phosphorus and nitrogen (HPN); while the organic fertilization replicated treatments were low and high chicken (LC, HC) manure and combination of high chicken and cow (HCC) manure. Each of the fertilization programmes had two untreated controls (CTRL), without fertilizer. All the Cyanophyceae (blue-green algae) than the CTRL, but HPN, produced vastly more algae that the others. The response pattern of Dinophyceae (dinoflagellates) was low. The organic trials responded to treatments, but more positively to HC and HCC in the zooplankton, and dominant genera encountered in both trials were Cladocera, Rotifera and Copepoda. The role of decaying plankton and organic manure as sources of detritus and carbon, providing nutrients in a vicious circle for optimum biological production is discussed in the light of food web sustainability in semi-intensive and intensive aquaculture systems.

Keywords: Fertilization, earth pond, phytoplankton, zooplankton and detritus.


FERTILIZATION OF EARTH PONDS II: EFFECTS ON MACRO INVERTEBRATES AND ECOLOGICAL INTER-RELATIONSHIP WITH AQUATIC MACROPHYTES

J. W. WADE AND H. P. STIRLING
Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, Scotland, U.K.
*Present address: Department of Zoology, University of Jos, Jos - Nigeria.

ABSTRACT
Organic fertilizers in form of cow and chicken manure were applied in oligotrophic or unproductive pond water over a period of one year to stimulate the production of benthic macro invertebrates for the benefit of trout culture, while maintaining adequate water quality. Development of aquatic macrophytes during both inorganic and organic fertilization in all the ponds was also evaluated with respect to the mutually beneficial relationship or `trade off' between the macrophytes and benthos. For the organic fertilization, replicate ponds were treated with low and high chicken manure (LC, HC), combination of high chicken and cow manure (HCC) and untreated controls (CTRL). The results showed that the application of HC and combination of HCC gave the highest numbers and biomass of benthos. The dominant groups encountered were in the order: Oligochaeta > Chironomidae > Asellidae > Sialidae > Hirudinea > Mollusca. Total abundance, biomass and dry weight production estimates of the benthos during the culture period were in the range, 3.5 - 134.0 x 103 ind. m-2; 26.0 - 113. gm-2 and 14.7 - 70.0g dry wt m-2 respectively. Throughout the inorganic and organic fertilization trials, pond 2, which was at various times treated with high phosphorus (HP) fertilizer and HCC had the most abundant macrophytes, with Elodea canadensis, Lemna mino, Glyceria fluitans and Alisma plantago-aquatica dominating, especially in the warm summer periods of July - August. The development of aquatic macrophytes in some ponds favoured production of some benthos, presumably due to greater foliage surface area that influenced plankton development, which are good sources of diet for the benthos. The results are discussed with respect to the mutually beneficial relationship or `trade-off' between the macrophytes and benthos, nutrient circulation and pond ecosystem stability.

Keywords: Fertilization, earth pond, macro invertebrates, macrophytes and ecological inter-relationship


STUDIES ON THE BIOLOGY OF LARVAE OF CLARIAS ALBOPUNCTATUS (N & L): EFFECT OF DIFFERENT DIETS ON THE GROWTH AND SURVIVAL OF LARVAE

J. N. AGUIGWO
Department of Biological Science, Nnamdi Azikiwe University, Akwa, Nigeria.

ABSTRACT
Clarias albopunctatus larvae, collected from the laboratory hatchlings were on the 4th day of lie, subjected to six different diet consisting of A - Plankton, B - Egg Yolk, C - Beef liver, D - Milk Powder, E - Crayfish trash and F - Soya bean meal. The experiment was maintained at 27.5 ± 5 0oC. Larval weight measurements before the experiment and later once in two days, were obtained, Larvae were fed to satiation, 4 times daily. Dead larvae were siphoned ad counted twice daily. The experiment ended on the 14th day and the respective groups were compared on the basis of growth rates, survival rates and food conversion ratios larvae fed on plankton diet were significantly higher than those fed on other diet. Larvae fed on soya bean meal had the lowest mean growth rates, survival rates and food conversion ratios. Survival rates of larvae fed on diets C and D; C and E; E and F were not significantly different between themselves but significantly differed from either A or B diet. Variations on the result suggests that larval age requires a period of live food feeding and this gradually will become replaced by artificially compounded feeds.

Key words: Diets, growth, survival, Clarias albopuctatus


THE SEASONAL FOOD HABITS OF OREOCHROMIS NILOTICUS (OSTEICHTHYS: SILURIFORMES) IN THE IKPOBA RESERVOIR, BENIN CITY, NIGERIA

F. A. OGUZIE
Department of Fisheries, University of Benin, Benin City, Nigeria

ABSTRACT
Stomach contents of 424 adult and juvenile Oreochromis niloticus netted from the Ikpoba Reservoir were analysed. Phytoplankton formed the dominant food items of the fish during the dry and wet months of the sampling period. Zooplankton population in the fish diet was more pronounced during the wet months. Blue green algae were found most frequently in the stomach of the fish followed by Diatoms and Green algae. Zooplankton (Cladocera and Copepoda) occurred less frequently in the diet of adults than juvenile fish. There was significant difference (P < 0.05) between the volume of food recorded in the fish stomachs during the dry and wet months of the year. Food abundance and feeding activity was heaviest during the dry than the wet months. The predominance of a wide variety of planktonic organisms in the fish stomachs suggested planktiphagous feeding habits.

Key words: Oreochromis niloticus, Ikpoba Reservoir, Stomach Contents.


HAEMATOLOGICAL CHANGES IN THE MUDFISH, CLARIAS GARIEPINUS (BURCHELL) EXPOSED TO MALACHITE GREEN

S. O. MUSA AND E. OMOREGIE
Fisheries Research Unit, Department of Zoology, University of Jos, Nigeria

ABSTRACT
The effect of sublethal concentrations of malachite green on blood compositions of the mudfish, Claris gariepinus (Burchell) was investigated under static bioassays during a 10 week exposure periods. Concentrations of malachite green used were 0.00 (control), 5.00, 10.00, 15.00, 20.00 and 25.00 µg1-1. The exposure led to anaemic response in the fish, this response was observed to be time and dose dependent. There was significant reduction in the neutrophils of the fish exposed to 15.00, 20.00 and 25.00 µg1-1. of the toxicant. The implications of these results were discussed with a suggestion of the total on the use of malachite green in aquaculture.

Keywords: Haematological, mudfish, Clarias gariepinus, malachite green.


THE EFFECT OF REFINERY EFFLUENT ON THE CHLOROPHYLL a AND GROSS PRIMARY PRODUCTIVITY OF RIVER RIDO

E. C. KEMDIRIM
Department of Biological Sciences, Nigerian Defence Academy, Kaduna

ABSTRACT
The effect of Kaduna Refinery effluent discharge on the chlorophyll a and gross primary productivity of river Rido was studied for 12 months at 3 stations in the river. Station 1 is the clean water station not affected by the discharge; stations 2 & 3 are the polluted area. The values for chlorophyll a and gross primary productivity were low in all the stations. Station 1 showed significantly higher (P < 0.05) chlorophyll a and gross primary productivity values than the other two polluted stations. Significant differences (P < 0.05) associated with the seasons were also observed in all the stations. The biological significance of these are discussed.

Keywords: Discharge, chlorophyll a, gross primary productivity, effluents, polluted.



THE EFFECTS OF TEMPERATURE ON EGG DEVELOPMENT IN THE AFRICAN MAYFLY POVILLA ADUSTA (EPHEMEROPTERA: POLYMITARCIDAE)

S. S. OGBOGU
Department of Zoology, University of Ibadan, Nigeria
Present Address: Department of Zoology, Obafemi Awolowo University, Ile-Ife, Nigeria

ABSTRACT
Egg masses were prepared from a packet of eggs of Povilla adusta Navas and incubated in the laboratory at constant temperatures and hatching success expressed by the logarithmic equation log Y = 0.14T + 1.42 (r2 = 0.028, P > 0.1). Hatching success was highest (84.85%) in eggs kept outside the incubator at laboratory temperature (33.2oC) followed by those incubated at 35oC (76.52%) and 30oC (65.46%) in that order. No hatching occurred in eggs incubated at 15oC, 20oC and 25oC. Minimum and mean incubated periods were the same at temperature at which eggs hatched. Hatching duration was short (1 - 2 days), which indicates synchronous hatching. A comparison of these results with previous findings suggests that Povilla adusta is warm adapted and as such, is confined to the tropical region in Africa where water temperatures are higher.

Key words: Mayflies, temperature, egg development, distribution, Africa.


Microbial flora of partially processed periwinkle (Tympantptonus fuscatus) from local markets in Port Harcourt, Nigeria

J. F. ALFRED-OCKIYA
Department of Fisheries, Rivers State University of Science and Technology, Port Harcourt, Nigeria.

ABSTRACT
A survey of microbial flora of partially processed periwinkles (Tympanotonus fuscatus) sold in six markets in Port Harcourt was undertaken for twelve weeks. Results show that all samples of periwinkles were contaminated with Staphylococcus aureus, Bacillus sp., Escherichia coil, Staphepidermidis sp., Micrococcus sp., Pseudomonas sp., and Klebsiella sp. Staphylococcus aureus was the most predominant 24.9% while Klebsilella sp. was the least 5.80%. The occurrence of Staphylococcus aureus, Bacillus sp., and Escherichia coil is indicative of a high pathogenicity and health hazard in consuming periwinkles. The need to critically re-examine our public health standards in the markets is advocated.

Key words: Microbial flora, periwinkles flesh, Port Harcourt, Markets.




EFFECTS OF KIDNEY BEAN, PHASEOLUS VULGARIS MEAL ON THE GROWTH PERFORMANCE, FEED UTILIZATION AND PROTEIN DIGESTIBILITY OF THE TILAPIA

K. V. ABSALOM, E. OMOREGIE AND A. M. IGBE
Fisheries Research Unit, Department of Zoology, University of Jos, Nigeria

ABSTRACT
Growth, feed utilization and protein digestibility in the fingerlings of the Nile tilapia, Oreochromis niloticus (mean weight 1.36 + 0.05 g) fed diets containing varying levels of the kidney bean, Phaseolus vulgaris were investigated under laboratory conditions. The kidney bean was incorporated at separate levels of 60, 40, 20 and 0% (control). The feeding period lasted for 8 weeks. There was no mortality recorded in all the various treatments, and the fish feed avidly throughout the feeding period. In general, the best growth and feed utilization results were obtained in fish fed the control diet, however, results obtained with the 60% kidney bean diet were satisfactory. Weight gain of the fish fed the control diet was 92s.02% , that fed on the 60% kidney bean diet was 71.22%, while that fed on the 20% kidney bean diet had the least weight gain value of 16.67%. Protein digestibility values in the control and 60% kidney bean diets were 85.04% and 81.04% respectively. There was no evidence of excessive fat or carbohydrate deposition in the fish muscle tissues after the feeding period.

Keywords: Growth, feed indices, digestibility, Tilapia, kidney bean


FLORA AND FAUNA OF ABIALA CREEK, NIGERIA DELTA, NIGERIA

V. F. OLALEYE1, AND O. A. AKINYEMIJU2
1Departmanet of Zoology, Obafemi Awolowo University, Ile-Ife, Nigeria 
2Department of Plant Science, Obafemi Awolowo University, Ile-Ife, Nigeria

ABSTRACT
Abiala creek is a typical aquatic weed infested creek in the Niger Delta Area of Nigeria. Examination of the aquatic vegetation revealed seven weed species dominated by Eichhornia crassipes (Mart.) Solm - Laub. The presence of these aquatic weeds negatively affected the plankton species diversity in the creek. The weed-free areas of the creek were qualitatively and quantitatively richer in plankton than the weed-infested areas. The aquatic weeds created an adverse environmental condition, which forced fish to migrate to the weed-free areas of the creek. The preponderance of male to female specimens and near absence of juvenile fishes was a reflection of the negative influence of the presence of the aquatic weeds on fish population structure. The predominating fish families - Polyteridae, Clariidae, Anabantidae and Channidae were discovered to have accessory respiratory organs.

Keywords: Eichhornia crassipes, aquatic weeds, plankton, diatom, Niger Delta, Nigeria.