404 resultados para feeding of fish
Resumo:
Survey of Fungal infestation of some species of fish in Tagwai Dam Minna was carried out from March to June 2002. Fungi were isolated from the scale/skin, gills and fins. Twenty-one fungi species were identified from 18 species of fish microbial growth was measured by direct cell count using Stuart colony counter. Most of the fungi encountered were of the mould group and infestation occurred among all the species sampled. The infestation was predominantly by Aspergillus species and the scale/skin was most widely affected. The study showed the identified fungi in order of frequency to be as follows. Aspergillius niger. Rrhizopus spp. Mmucor spp Aspergilus flavum. Aspergillus parasitous. Aspergillus fumigatus, Microsporum canis. Penicillum virridicalumand Fusarium spp respectively. Aspergillus niger occurred on all the species of fish sampled. Barrilius spa and Chrysichrhy auratus longifilis had significantly higher (P<0.05) mean fungal load on their fins and gills. There was no significant difference (P>0.05) in the mean fungal load in different parts of the body of other fish species sampled
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The notions about women been limited to producing children like rates alone; cooking for the family, restricted within the fenced compound without any meaningful contributions in fish food production was dispelled during the course of the study. From the data gathered, the study revealed various contributions of women as regard fish food production as about 2% of the women are involved in direct fishing as this enhance food security of the family and the society. Also women dominate the entire post harvest and marketing sector and 70% started fishing business with their personal savings.Also, some of the women own boats and other fishing inputs, which they do give to the fishermen that could catch the fish and sell it to them. This has a way of enhancing fish catch and fish food security of the people as those men that would have sit idle for lack of fishing gears are now meaningfully engaged courtesy of the women financiers. Finally, the study also revealed that 46% of the women between N2,5000 to above N4,000 from marketing of fish, and also utilizenthe income generated to enhance the welfare of the households in the area of food, clothing and paying their children school fees hence reducing the level of poverty of their households
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Rapid Appraisals of the current fisheries situations of some selected inland water bodies in Nigeria were carried out within the framework of Aquaculture and Inland Fisheries Project (AIFP) Annex II of the National Special Programme for Food Security (NSPFS). This paper presents the results of the fishery assessment of one of the selected inland water bodies (Sabke Lake) in Nigeria with a view to optimizing the fish yield through the adoption of improved culture based fishery techniques and community-based fisheries management. The lake is unmanaged and the fishing pressure was found to be very high. Also a number of fishermen were found using small mesh size nets to crop the juveniles of highly valued fish species for an optimum catch. About 14 fishermen ought to have been engaged in full time fishing activities if the fisheries of this lake is to be managed on a sustainable basis. However, a surplus of over 100 fishermen was recorded actively fishing during the period of the study. The results further revealed that Fisheries Rules and Regulations were not established for the national exploitation and proper management of the fisheries of many inland water bodies including Sabke Lake. All these have a depilatory effect on the abundance and sizes of fish harvested from the nigerian inland water bodies especially Sabke Lake. A community based management system that establishes a participatory involvement of fishermen in the conservation and national exploitation of fisheries resources for their own well being is recommended for Sabke Lake and other inland water bodies in Nigeria
Resumo:
In this reservoir, the parameters being assessed are very important in the aspect of fish culture. These parameters are: physical parameters which includes temperature (O), Transparency (M).Chemical parameters include: Dissolve oxygen (mg/l) pH concentration and the Biological Parameters which include phytoplankton and zooplankton. The phytoplankton and zooplankton identification and estimation were carried out in the NIFFR Limnology Laboratory, (Green House), New Bussa. Each identified zooplankton and phytoplankton species was placed according to its major group e.g. zooplankton was grouped into three families, Roifera, Cladocera and Copepods. During this study period it was observed that copepods have the highest total number of zooplankton both beside the poultry and monk (station 'A'&'B'). Water temperature of station 'A' (beside the poultry house) ranges from 27 C-29, 5 c also same station 'B' (near the monk). Dissolve oxygen station 'A' range from 6.30mg/l-7.40mg/l while that of station 'B' ranges from 6.20mg/7.50mg/l, turbidity reading of station A'ranges from 0.19m-0.3m while station 'B' ranges from 0.22m-0.37m. The last parameter, which is pH concentration, in both stations 8.2 was observed this is an indication that the pH was constant. According to some literature review all the water parameter figures obtained were good for fish culture
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This paper focuses on the financial analysis involved in setting up of fish farming on a small-scale in a homestead. About 0.5 acres of land was used for the construction of pond which as a stock of Clarias spp/ Heterobranchus spp and Tilapia spp at the ratio of one to three for a period of 12 months. The land/land development cost is N26,500.00, pond construction cost, N35,700.00, equipment cost, N2,650.00 and stock/Input requirement cost N155,727.00 while the revenue from sales is N376,000.00. A cash flow analysis is also calculated for the fish farm, which is N155,423.00 for first year cash flow, and appropriate profit/mosses were calculated for five-year production cycle of N1,036,515.00 million. At the end appreciable profit is realized from the enterprises. This type of enterprises is viable for small-scale farmers to practices and adopted for financial support for their family
Recruitment pattern and fish production within the Andoni River system in the Niger Delta of Nigeria
Resumo:
Biweekly samples of fish species obtained from five randomly selected Andoni artisanal fisheries within the Andoni River system, Niger Delta of Nigeria were collected between January and December 1999 and their length frequencies analyzed using FISAT (FAO-ICLARM STOCK ASSESSMENT TOOL). The peak recruitment period for Chrysichthys nigrodigitatus, Ethmalosa fimbriata, Eucinostomus melanopterus, Galeodes decadactylus, Pomadasys jubelini and Sarotherodon melanotheron constituting 54.55% was between June and October while Liza grandisquamis and Lutjanus goreensis, Ilisha Africana. Tilapia guinensis and Pseudotolithus elongate constituting 27.27% had two peak recruitment periods including March-May and May- October. In view of this result it is advisable for fishers to intensify fishing effort between May and October for most commercially important fish species for bountiful harvest
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A study of the composition and distribution of fish populations in the inshore, surface and bottom water habitats of Kangimi Reservoir showed that the most abundant family was the Cichlidae followed in order of abundance by the familiesCyprinidae, Schilbeidae, Mormyridae, Mochokidae, Characidae, centropomidae and Bagridae. Though the overall composition of families caught inn the three habitats did not vary significantly (P>0.05) only family Cichlidae showed habitat preference: there was a preponderance of Cichlidae in the inshore water habitat (P<0.05). The families Bagridae and Centropomidae were caught only in the inshore and bottom water habitats while the other families were caught from all habitats and showed no habitat preference. The dominance of primary and secondary consumers indicates high fish production potential under adequate management
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Tanzania Fisheries Research Institute being currently the only fisheries research institute in Tanzania has sole responsibility of marking the presence and distribution of fish species in the country. This work is expected to be completed by the year 2005. In order that this work can be accomplished, both published works and field observations (including geographical location using GPS) have to be compiled. Since the institute has centers in all the Great Lakes and one along the Indian Ocean coast, it is expected that field observations and identifications will be obtained and incorporated into the document to be produced by 2005. (PDF contains 15 pages)
Resumo:
The proposed EC Water Framework Directive (WFD) will require member states to monitor both biotic and abiotic components of lake environments. With adoption of the WFD some measurement of fish populations will also be required. This paper describes work carried out since 1971, and particularly since 1991, on the status of fish populations in Lower Lough Erne, Northern Ireland, with an emphasis on defining change over time due to human impacts on the lake. This offers a reasonable starting point from which to develop a monitoring programme suitable for the needs of the WFD in this lake. The implications for as yet unmonitored fish populations in lakes are also determined.
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Abstract Growth and condition of fish are functions of available food and environmental conditions. This led to the idea of using fish as a “consumption sensor” for the measurement of food intake over a defined period of time. A bio-physical model for the estimation of food consumption was developed based on the von Bertalanffy model. Whereas some of the input variables of the model, the initial and final lengths and masses of a fish and the temperature within the time period considered can easily be measured, internal characteristics of the species have to be determined indirectly. Three internal parameters are used in the model: the maintenance consumption at 0°C, the temperature dependence of this consumption and the food efficiency, the percentage of the ingested food utilized. Estimates of the parameters for a given species can be determined by feeding experiments. Here, data from published feeding experiments on juvenile cod, Gadus morhua L., were used to validate the model. The average of the relative error for the food intake predicted by the model for individual fish was about 24 %, indicating that fish used the food with different efficiencies. However, grouping the fish according to size classes and temperature lowered the relative error of the predicted food intake for the group to typically 5 %. For a group containing all fish of the feeding experiment the relative prediction error was about 2 %. Zusammenfassung Wachstum und Kondition der Fische sind von der verfügbaren Nahrung und von Umweltbedingungen abhängig. Dies führte zur Idee, Fisch als „Konsum-Sensor“ für die Messung der Nahrungsaufnahme über einen definierten Zeitraum zu verwenden. Auf Grundlage des von Bertalanffy-Modells wurde ein bio-physikalisches Modell zur Schätzung der Futteraufnahme entwickelt. Während einige der Eingangsgrößen des Modells leicht gemessen werden können (Anfangs- und Endlänge und -körpermasse der Fische und die Temperatur innerhalb des betrachteten Zeitraum), können interne Parameter der betrachteten Art nur indirekt bestimmt werden. Drei interne Parameter werden in dem Modell verwendet: Die Erhaltungskonsumtion bei 0° C, die Temperaturabhängigkeit dieser Rate und der Wirkungsgrad der Nahrung (der Anteil der Nahrung ,der aufgenommen und verwendet und nicht ungenutzt wieder ausgeschieden wird). Die Modellparameter für eine bestimmte Art können durch Fütterungsversuche bestimmt werden. Um das Modell zu validieren wurden Daten aus veröffentlichten Fütterungsversuchen mit juvenilen Kabeljau (Gadus morhua L.) verwendet. Modell und Wirklichkeit weichen in der Regel voneinander ab. Der durchschnittliche relative Fehler der durch das Modell vorhergesagten Nahrungsaufnahme betrug für Einzelfische etwa 24%, was darauf hinweist, dass einzelne Fisch die Nahrung mit unterschiedlichen Wirkungsgraden verwerten. Allerdings senkte die Gruppierung der Fische nach Größenklassen und Temperatur den relativen Vorhersagefehler für die Nahrungsaufnahme der Gruppe auf etwa 5%. Für alle Fische im Fütterungsversuch ist der relative Vorhersagefehler etwa 2%.
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The significance of detritus in the nutrition of aquatic animals, especially of the small representatives of the zooplankton, has been studied very slightly. Research so far has established that in M. rectirostris with feeding on protococcal and single-celled green algae and bacteria the beginning of formation of eggs takes place in 2 - 4 days. The young appear in 4 - 6 days. In this study M. rectirostris and C. quadrangula are fed on detritus of natural origin in laboratory conditions. In order to determine the assimilability and productive: effect of detritus, the author set up experiments, permitting to characterize the rate of growth, speed of maturing and fertility of M. rectirostris and C. quadrangula with feeding of them on detritus of different composition and age.
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The identification of fish zones in western and central Europe has been the objective some major studies. This paper concerns a stream in Normandy specially studied by the author in 1969 and 1970 in the framework of a study on the role of the mean temperature in fish zoning. The paper propounds the comparative study of the morphodynamic and occasionally physico-chemical characteristics, as well as the results of previous sampling by electric fishing of the fish populations of two other streams of the higher Cretaceous layer and supplied by ”chalky” water in Normandy and Picardy.
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This book section analyses the role of fish processing factories in the process of co-management related to the LVFRP.
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The number and size composition of gillnets, fishing grounds, and the quantity and composition of fish catches were related to the size of fishing boat. The overall number of gillnets per boat increased from 20.9 + or - 2.3 nets in 5-6 m long boats to 88.6 + or - 11.8 nets in 11-12 m long boats. The proportion of large mesh sizes, + or more than 127 mm, also increased from 40% in 5-6 m long boats to 100% in boats longer than 10 m. Fish catches are related to the size of boat and this should be considered when formulating management guidelines of the lake's fishery. Promotion of large fishing boats 8 m or longer and restriction on the number and/or mesh size of gillnets of smaller boats could increase ecological and socio-economic benefits.
Diet and condition of American Alligators (Alligator mississippiensis)in three central Florida lakes
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Understanding the diet of crocodilians is important because diet affects condition, behavior, growth, and reproduction. By examining the diet of crocodilians, valuable knowledge is gained about predator-prey interactions and prey utilization among habitats. In this study, I examined the diet and condition of adult American alligators (Alligator mississippiensis) in three central Florida lakes, Griffin, Apopka, and Woodruff. Two hundred adult alligators were captured and lavaged from March through October 2001, from April through October 2002, and from April through August 2003. Alligators ate a variety of vertebrate and invertebrate prey, but vertebrates were more abundant and fish dominated alligator diets in the lakes. Species composition of fish varied among the lakes. The majority of the diet of alligators from Lakes Apopka and Woodruff was fish, 90% and 84% respectively. Lake Apopka alligators consumed a significantly (P = 0.006) higher proportion of fish in their diet. Fish were 54% of the diet of Lake Griffin alligators and the infrequent occurrence of reptiles, mammals, birds, and amphibians often resulted in a large biomass. Differences in alligator diets among lakes may be due to differences in sample size (higher numbers of samples from Lake Griffin), prey availability, habitat, prey vulnerability, or prey size. Alligator condition (Fulton’s Condition Factor, K) was significantly (P < 0.001) different among the lakes. Alligators from Lake Apopka had the highest condition, followed by those from Lake Griffin, and alligators from Lake Woodruff had the lowest condition. Composition of fish along with diversity and equitability of fish in alligator diets may have contributed to differences in condition among lakes. Condition was probably also due to factors other than diet such as alligator hunting behavior, alligator density, or year-round optimal temperature that prolongs feeding. The observed diet and condition differences probably reflect both habitat differences and prey availability in these three lakes.