537 resultados para REEF FISH ASSEMBLAGE
Resumo:
This study provides information on fish quantities, economic data and flows of Doro fish market near Baga, Nigeria, known as the major fish market on the Nigeria section of the Lake Chad
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The involvement of women in the marketing of frozen fish in Lagos State (Nigeria) was examined in this study. Two hundred questionnaires were administered to fish marketers in five markets randomly selected within the Lagos metropolis based on their storage capacities. These markets were Balogun (500 tones), Idumagbo and Idumota (250 tonnes each) Obalende and Epetedo (37.5 tonnes each). From the study results, a greater percentage of women (64.2%) are actively involved in marketing of frozen fish in the study areas. Over 56% of these traders are retailers while about 33% are wholesalers. More than 91% of the marketers were found to be literate. A high percentage of the frozen fish are imported (68%), 27% from coastal fishing and 5% from riverine fishing. The commonest fish in the markets were titus (34%), sardine (32%), hake 19%, catfish 10% and argentine 5%. Catfish has the highest profit margin. The greatest problem of these traders is the lack of modern storage facilities and where available, the erratic power supply constitutes a problem
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A five months survey was conducted to identify the aquatic macrophytes in fishponds and reservoirs in Makurdi (Benue State, Nigeria) between August and December 1999. A total of 3-prominent aquatic macrophytes were identified: Ipomoea aquatica, Nymphae lotus and Echinochloa pyramidalis at two-study sites (site 1, receives organic manure effluent from a cattle ranch, site 2, receives inorganic fertilizer through application). Ipomoea aquatica were found restricted to site l, while Nymphae lotus and Echinochloa pyramidalis were found associated with site 2. Analysis of the results indicates high level of ammonia-nitrogen at site 1 compared to site 2. Mineral analysis of the plant tissues indicate high level of iron in Ipomoea aquatica and Nymphae lotus. Mineral concentration were found to be significantly higher (P,L, 0.05) in Ipomoea aquatica and Nymphae lotus when compared with concentration in Echinochloa pyramidalis
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The food and feeding habits of Tilapia zillii in the fish farm of Ondo State University, Akungba - Akoko, Nigeria, were studied by gut analysis. Examinations of 150 specimens showed that Nymphea formed the main bulk of food consumed. Spirogyra, Pithophora and Compsopogon occurred frequently while Pistia detritus and plant remains featured less frequently. Variation in the frequency of occurrence of the various food items was observed among the various sizes of samples. The samples within the middle - size group fed on both higher plant and filamentous algae while the young and higher fish consumed exclusively filamentous algae. On the basis of food items found in the gut, Tilapia zillii was classified as primary consumers
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Fish farming practices in the Lake Kainji Area of Nigeria are categorized under seven main cultural facilities, namely, earthen ponds/reservoirs, indoor/outdoor concrete tanks, plastic tanks, floating cages/hapas, aquaria, sewage and feral conditions. The presence of Bacteria isolates associated with diseased fish conditions varied significantly (P<0.05) with different cultural facilities. The highest bacteria isolates and bacterial disease incidence, 33% and 46% respectively, was associated with diseased fish in the indoor/outdoor concrete tanks. The least incidence of bacteria isolates (3.5%) and blue bacterial disease (3%) was associated with diseased fish in the aquaria and feral conditions. Nine Gram-negative and two Gram-positive bacteria genera were isolated during this investigation. Pseudomonas spp. (23.6%) and Staphylococcus spp. (14.3%), were the predominant Gram-negative and Gram-positive bacteria genera in the different cultural facilities, respectively. This paper highlights the relevance of occurrence and distribution of bacteria isolates associated with diseased fish to bacterial fish diseases under different cultural facilities
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Fish sorting assessments of Clarias gariepinus fingerlings stocked and raised in fish tanks were undertaken for a 6-month culture period: Sorting was undertaken from the first, second, and third months of stocking the fish fingerlings while the control was not sorted at all. The sorting assessments revealed that the twice sorting of fish fingerlings stocked with a Marginal Rate of Return (MRR) of 3.44 was significantly different (p>0.05) from those sorted once with MRR of 0.912, and three times with MRR of 2.65 respectively, thus making twice sorting most advisable for fish farmers utilizing Clarias gariepinus fingerlings for tank aquaculture
Resumo:
A five months survey was conducted to identify the aquatic macrophytes in fishponds and reservoirs in Makurdi (Benue State, Nigeria) between August and December 1999. A total of 3-prominent aquatic macrophytes were identified: Ipomoea aquatica, Nymphae lotus and Echinochloa pyramidalis at two-study sites (site 1, receives organic manure effluent from a cattle ranch, site 2, receives inorganic fertilizer through application). Ipomoea aquatica were found restricted to site l, while Nymphae lotus and Echinochloa pyramidalis were found associated with site 2. Analysis of the results indicates high level of ammonia-nitrogen at site 1 compared to site 2. Mineral analysis of the plant tissues indicate high level of iron in Ipomoea aquatica and Nymphae lotus. Mineral concentration were found to be significantly higher (P,L, 0.05) in Ipomoea aquatica and Nymphae lotus when compared with concentration in Echinochloa pyramidalis
Resumo:
The chemical composition of Azolla africana and Spirodela polyrrhiza cultivated in earthen ponds were determined. Crude protein contents of the samples were 28.9~c0.6 and 25.6~c0.2% dry matter for A. africana and S. polyrrhiza respectively. Dry matter, crude fibre and lipid contents of A. africana were higher (P<0.05) than values obtained for S. polyrrhiza. Mineral analyses showed that S. polyrrhiza contained higher levels of Na, S, Ca, Mg and Fe than A. africana. Except for Ca content in S. polyrrhiza, heavy metals (Ni and Zn) accumulation in Azolla were very high. There were no wide differences in the individual amino acid indexes except for methionine. Some anti-nutritional factors were determined. Cyanide, tannin and phytin contents of fresh weed samples were higher than sun-dried samples. A. africana contained more cyanide and tannin than S. polyrrhiza both in fresh and sun-dried forms
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The distribution of Oreochromis niloticus was studied in Opa reservoir (Nigeria) using a graded set of gillnets while the food and feeding habits were studied using a castnet to collect the fish samples. About 90% of the fish specimens were caught near the reservoir bottom while about 69% of the specimens were caught within the inshore area of the reservoir. The species fed mainly on detritus, algae and higher plants. Feeding rhythm in O. niloticus started around 6.00 a.m. and reached a peak by 3.00 p.m. but then declined gradually until 6.00 p.m. These results can be utilized for the proper management of the fish species in the reservoir
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The monthly and seasonal water requirements of a small fish pond (0.068ha; maximum capacity of 613.83m super(3)) at the University of Agriculture, Makurdi Fish Farm (Benue, Nigeria) were determined during the period of February to August 1996. The sources of water for the pond were rainfall, (103.4cm), run-off (6.3cm) and regulated inflow (95.0cm). The water loss for the period were Evapotranspiration, (106.74cm), Seepage (71.64cm) and regulated discharge (25.00cm). Evapotranspiration was identified as the main source of water loss while rainfall was the major source of water gain. The mean monthly water deficit was 24.56~c11.43cm while the mean monthly surplus was 9.84~c8.05cm. The quantity of water required to maintain the optimal water level in the pond was 474.00m super(3). Preliminary water budget of the study area showed that rainfed aquaculture can be effectively carried out at Makurdi during the months of June to October with supplementary inflows during the dry season months
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The fisheries of Lake Kainji, Nigeria, experienced a boom year following impoundment, then decline post impoundment and now is in a period of stabilisation of the fish resources. Several reasons have been advanced on factors responsible for these changes, but two outstanding factors are those of nutritional status and fishing methods of the lake. Two important fish families however continue to dominate the lake fisheries in daily fisherman catches: Clupeidae and Cichlidae (tilapias). Recent studies have also shown that the dominance of the tilapias and clupeids is an important factor in the understanding of the stability of fisheries of Lake Kainji. One area which has remained undiscussed concerns the parasites and non-fish predators of tilapias which can affect the population dynamics of tilapias. This paper examines therefore some aspects of the fisheries of Lake Kainji and the potential roles that parasites and non-fish predators of tilapias can contribute in developing strategies for consideration in the sustainable management of the fisheries
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This study examines acute toxicity of Raphia vinifera on fish leech, Piscicola geometra. The leeches with a mean total length of (TL) 4.2+1.0cm were exposed to various concentrations of both crude powdered and ethanolic extracts of the botanical. Median lethal concentration (LC50) was determined with static-renewal tests using logarithmic and arithmetic graphic methods. The LC50 (for 96 hours of crude powdered (aqueous) extracts of the botanical on Piscicola geometra was 1.10 ppm arithmetically and 1.14ppm logarithmically. The 95% confidence limits was 0.10ppm arithmetically and 0.12ppm logarithmically. The LC50 of ethanolic extract of the poison at 96-h was 0.5ppm arithmetically and 0.48ppm logarithmically. The 95% confidence limits were less than 0.10ppm. The use of extracts of R. vinifera in the control of leeches in fish ponds is discussed
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Details are given of a study carried out in Nigeria, to introduce the practice of fish-cum-rice culture, using Sarotherodon galilaeus. Two plots each measuring 360m super(2) were used for this study and were compared with the farmer's two plots measuring 300m super(2) and 350m super(2). The plots were modified and had two central canals. Rice seedlings were transplanted into the plots after 19 days using a planting distance of 20 x 20cm. Three rice seedlings were planted per hole, using rice variety FARO 40, and grown for 90 days. About 240 and 180 S. galilaeus fingerlings of mean weight of 30g and 26g were stocked in the two experimental plots, respectively. They were fed with pelleted feed of 25% C.P. and monitored for 100 days. A yield of 22.8kg was obtained in plot A while 15.66kg was obtained in plot B. A rice yield of 250kg (i.e 5 bags) was obtained in each of the plots. The results obtained were compared with plots with no fish
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The findings are presented of a study conducted to assess the post harvest losses in Shiroro Lake, Nigeria. The major objectives were to identify and quantify the types of losses, to provide recommendations that would enhance formulation of policy guidelines for utilization and exploitation of the declining fishery resources of the lake
Resumo:
The paper enumerated the following ways of improving fisheries:- Effective implementation of the inland fisheries Decree of 1992, stocking and introduction of new species in to small and medium size reservoirs, enhancement of fish catch through increased artisanal fisheries development, fish hatchery development in strategic zones for increased fingerling production to stock reservoirs and natural water bodies, extensive culture development in flood ponds, and encouragement of commercial aquaculture under private entrepreneurship. The paper further elaborate on the strategies for effective implementation of the above guidelines with the hope of offering solution to problems hindering production in Nigeria