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Schutter, M. (2010)
The influence of light and water flow on the growth and physiology of the scleractinian coral Galaxea fascicularis
Zooxanthellate scleractinian corals are sessile colonial animals that live in symbiosis with photosynthetic algae, the zooxanthellae. They can feed both phototrophically and heterotrophically and produce an external skeleton of calcium carbonate, which process is enhanced by light. They are the key organisms of tropical coral reefs and responsible for building the large carbonate structures. Tropical coral reefs are increasingly threatened by both natural and anthropogenic stresses. >> more info... |
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Nieuwegiessen, P.G. van de (2009)
Welfare of African catfish : effects of stocking density
In the Netherlands, the welfare of farmed fish is subject of growing public and governmental concern. Comparable to concerns regarding the intensity of terrestrial livestock production, stocking densities applied in fish farming have been highlighted as an important area of welfare concern. The general aim of this thesis was to determine the impact of stocking density on welfare indicators in African catfish, Clarias gariepinus, cultured in a recirculating aquaculture system. >> more info... |
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Nematollahi, M.A. (2008)
Characterization of the stress response in 17a-hydroxylase deficient common carp (Cyprinus carpio L.)
In this thesis we describe interrenal hyperplasia in a teleost fish, the common carp, Cyprinus carpio L, caused by 17α-hydroxylase deficiency. Two homozygous, XX male inbred strains, “E5” and “E7”, consistently show 5-10 fold less plasma cortisol in response to net confinement compared to normal male and female carp strains. Both E5 and E7 fish have enlarged head kidneys, which is caused by an increase in size and number of interrenal cells. The experiments and results described in this thesis aim to provide further insight into the genetic background of the 17α-hydroxylase deficiency, and the expression of genes involved in the stress response in P450c17 deficient common carp during and after stress. >> more info... |
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Tran Duy, A. (2008)
Modeling the effects of dietary carbohydrate and ambient oxygen concentration on feed intake and growth in fish
Fish production can lead to discharge of wastes and have negative impacts on the environment. It is therefore important to carefully monitor and plan the development of aquaculture. A model that can simulate fish growth on the basis of available fish species and local conditions (like water quality and quantity and quality of fish feed) could therefore be extremely useful. Since growth strongly depends on feed intake, a growth model should be able to predict maximum feed intake of fish under ad libitum feeding. This thesis aimed at investigating some potential mechanisms for feed intake regulation and predicting maximum feed intake in the light of these hypothesized mechanisms using a theoretical modeling approach. >> more info... |
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Urán Carmona, P.A. (2008)
Etiology of soybean-induced enteritis in fish
The inclusion of soybean meal (SBM), especially in the diet of Atlantic salmon, induces an inflammatory response of the distal intestinal mucosa, known as SBM-induced enteritis. A semi-quantitative scoring system was developed to assess the extent of the morphological changes observed in this study. The influence of SBM feeding has been investigated taking into account several dietary and non-dietary factors possibly involved in the induction of the disorder. It has been found that the severity of enteritis and its kinetics are dose-dependent. Electron microscopy studies indicated a block of the endocytosis process and a strong decrease of the microvilli length. >> more info... |
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Bosma, R.H. (2007)
Using fuzzy logic models to reveal farmers' motives to integrate livestock, fish, and crops
Rural extension services have changed paradigm and shifted to more participatory approaches, whereas in common mathematical models of farming systems, farmers’ motivation is solely represented by ‘utility maximisation’. While globally, farmers specialise, in Vietnam the rice-based systems have diversified into more sustainable integrated agriculture–aquaculture. We gathered data from 144 farms in six villages in two ecological zones of the Mekong Delta, Vietnam. Using the livelihood framework we conceptualised farmers’ decision-making in a fuzzy logic model that can deal with subjective linguistic statements through ‘if–then’ rules. >> more info... |
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Nhan, D.K. (2007)
The role of a fish pond in optimizing nutrient flows in integrated agriculture-aquaculture farming systems
In the Mekong delta, the Vietnamese government promoted integrated agriculture-aquaculture (IAA) farming systems as an example of sustainable agriculture. An important advantage of IAA-farming is the nutrient linkage between the pond and terrestrial components within a farm, which allows to improve resource use efficiency and income while reducing environmental impacts. This study monitored and analyzed water use in and nutrient flows through ponds that are part of an IAA-farming system. The goal was to improve the nutrient management of ponds which in turn lead to improved water and nutrient use efficiency of the whole IAA-farm. >> more info... |
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Tsehaye, I.W. (2007)
Monitoring fisheries in data-limited situations : a case study of the artisanal reef fisheries of Eritrea
Elucidating trends in catch rate and composition is important to evaluate the impact of fishing on fish stocks, and thereby guide fisheries management action. Since major changes in fish community structure can take place even at the initial stages in the development of fisheries, the onset of reef fisheries in the Eritrean Red Sea provides a good opportunity to assess the effects of fishing on fish community structure in the early stages of fisheries. The artisanal reef fisheries of Eritrea were launched into a renewed development in 1991 after the end of a decades-long standstill, which was caused by the war for Eritrea’s independence. >> more info... |
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Uddin, S. (2007)
Mixed culture of tilapia (Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) in periphyton-based ponds
In recent years, the concept of periphyton-based aquaculture has been tested and applied in aquaculture. Positive effects of substrate addition for periphyton development included increasing the food supply and providing shelter for culture animals. The aim of this project was to develop a low-cost culture technology for resource-poor farmers in South-East Asia. The technology is an extension of traditional brush-park fisheries in which bacteria, protozoa, fungi, phytoplankton, zooplankton, benthic organisms and a range of other invertebrates colonized the substrates installed in rivers and lakes, attracting many fishes. These microbial communities are an excellent food for fishes or crustaceans. >> more info... |
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Winter, H.V. (2007)
A fisheye view on fishways
Barriers in rivers severely obstruct fish migration. To mitigate the impact, different types of fishways have been developed to facilitate upstream movements of fish. In this PhD-thesis the effect of a series of V-stepped fishways alongside weirs in the regulated River Vecht, the Netherlands, was evaluated. In the period before the fishways were built, only during high discharge events weirs were lowered and strong swimmers were able to pass. Based on daily water levels, discharge and a sprinting capacity model, an assessment was made of the migratory opportunities during the pre-fishway period. >> more info... |
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Charo-Karisa, H. (2006)
Selection for growth of Nile tilapia (Oreochromis niloticus L.) in low-input environments
Nile tilapia (Oreochromis niloticus L.), is one of the most important species farmed in the world and is the mainstay of many resource-poor fish farmers. The majority of its culturing is carried out in semi-intensive systems with a wide array of pond inputs from the farm. These systems are characterized by poor fish growth and low yields. Studies have shown that only a small percentage of the nutrient input in these systems is converted to harvestable products. >> more info... |
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Fessehaye, Y. (2006)
Natural mating in Nile tilapia (Oreochromis niloticus L.) : implications for reproductive success, inbreeding and cannibalism
Niletilapia ( Oreochromis niloticus L.) is one of the most important species among the commercially farmed tilapias. Both small-scale and commercial production of tilapia is rapidly expanding in many countries of the world because tilapias meet many of the desirable characteristics for an ideal species for aquaculture: fast growth, high acceptability to consumers and tolerance of a wide range of culture conditions. Fry production in Niletilapia, Oreochromis niloticus is typically achieved by mass-spawning of males and females stocked in large hapas, earthen ponds or tanks. >> more info... |
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Ginneken, V.J.T. van (2006)
Simulated migration of European eel (Anguilla anguilla, Linnaeus 1758)
The European eel ( Anguillaanguilla L.) is a catadromic fish species with its spawning grounds thousands of kilometers away in the ocean, possibly theSargasso Sea. The objective of this study was to elucidate this oceanic phase of migration for the European eel (Anguillaanguilla L.) in the laboratory. >> more info... |
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Kaggwa, R.S. (2006)
Fingerponds: managing nutrients and primary productivity for enhanced fish production in Lake Victoria's wetlands, Uganda
Wetlands are of great ecological importance and have been described as the most important zone for freshwater fisheries. They can be exploited for agriculture and aquaculture through the integration of these activities. In Sub-Saharan Africa, emphasis has been put on agriculture and this has 1ed to the degradation of these ecosystems. With the ever-increasing population rise, many of the wetlands are encroached on and degraded. These wetlands are best managed under the framework of a 'working wetland' which ensures a rational compromise between ecological condition and the level of human utilization. >> more info... |
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Kipkemboi, J. (2006)
Fingerponds: seasonal integrated aquaculture in East African freshwater wetlands : exploring their potential for wise use strategies
This study was stimulated by the need for an integrated approach in wetland wise use. Sustainable management is critical for long-term ecosystem health and people's livelihoods. The potential for smallholder integrated agriculture-aquaculture as one of the possible wetland wise use strategies was explored in two sites on the northern Kenyan shores of Lake Victoria: Kusa and Nyangera. >> more info... |
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Muendo, P.N. (2006)
The role of fish ponds in the nutrient dynamics of mixed farming systems
Rapid population growth in developing countries has resulted in increased demand for food, leading to increased pressure to extend land under cultivation and to intensify food production. Because most of the arable land has already been utilized, further intensification of agricultural production has involved conversion of marginal lands such as forest reserves, communal grazing land & and fragile areas such as river banks and steep hill slopes. >> more info... |
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Rahman, M.M. (2006)
Food web interactions and nutrients dynamics in polyculture ponds
Artificial feed and fertilizers are the main sources of nutrients supporting fish growth in aquaculture ponds. The majority of the added nutrients are lost to the sediment, where they are no longer available for natural food production. By increasing resuspension of the sediment through the introduction of benthivorous fish, nutrient loss may be reduced, because of the re-mobilisation of nutrients from the sediment. The effects of addition of benthivorous fish and/or artificial feed in fertilized ponds have mostly been studied separately. >> more info... |
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Schneider, O. (2006)
Fish waste management by conversion into heterotrophic bacteria biomass
Just as all other types of animal production, aquaculture produces waste. This waste can be managed outside the production system, comparable to terrestrial husbandry systems. However, particularly recirculation aquaculture systems (RAS) are suited to manage waste within the system. In this case, processes have to be selected to convert the waste into a re-usable product. Dissolved and solid waste conversion by heterotrophic bacteria is one of these processes. >> more info... |
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Amirkolaie, A.K. (2005)
Dietary carbohydrate and faecal waste in the Nile Tilapia (Oreochromis niloticus L.)
Public concerns about environmental pollution are putting increasing pressure on fish farms to treat their wastewater before release. The wastewater produced by the fish can also deteriorate water quality within the system. Aquaculture waste can be divided into solid waste and dissolved waste.Faeces ismain sources of solid waste. An increased consistency of faeces may improve its removal efficiency, thereby improving water quality. The removal efficiency of faeces by a collector (settling tank and/or Choubert) was proposed as an indicator for faeces consistency. >> more info... |
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Matos Martins, C.I. de (2005)
Individual variation in growth of African catfish Clarias gariepinus: a search for explanatory factors
Among farmed animals, fish exhibit the largest individual variation in growth, yet most of the studies reporting data on growth do not take individual variation into account. Usually a mean value is considered and although the variation around the mean is also mentioned, it is generally viewed as a sort of "statistical noise". The importance of individual variation in growth should not be underestimated since it has important consequences for water quality, aggression, stress levels, farm management, selection programmes, etc. >> more info... |
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Rutten, M.J.M. (2005)
Breeding for improved production of Nile tilapia (Oreochromis niloticus L.)
The aim of this thesis was to generate knowledge that supports the design of breeding programs for Nile tilapia targeting genetic improvement of body weight and fillet yield to serve the European market. To this end, both the genetic variation and the performance levels of different strains of tilapia were investigated within intensive recirculation systems. Molecular genetic variation was investigated by use of microsatellite markers on four domesticated strains of tilapia. >> more info... |
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Torres Beristain, B. (2005)
Organic matter decomposition in simulated aquaculture ponds
Different kinds of organic and inorganic compounds (e.g. formulated food, manures, fertilizers) are added to aquaculture ponds to increase fish production. However, a large part of these inputs are not utilized by the fish and are decomposed inside the pond. The microbiological decomposition of the organic matter is a critical factor for water quality control and nutrient recycle. Usually, management practices are developed to control the survival and health of the cultured animals and to maintain good water quality. >> more info ... |
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Almazán Rueda, P. (2004)
Towards assessment of welfare in African catfish, Clarias gariepinus: the first step
Usually, farming implies that animals are kept in small areas in densities above the ones found in natural populations. These conditions may evoke reactions of impaired welfare when the animal is not well adapted to cope with its surroundings and conspecifics. In such cases, different behavioural patterns may occur, from reduced feed intake, to aggression and death. Information about the animal in such conditions may help us to understand its welfare. >> more info … |
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Bucio Galindo, A. (2004)
Lactobacillus plantarum 44a as a live feed supplement for freshwater fish
In the last years, aquaculture has become a very fast growing sector in animal production. However, the number of outbreaks of bacterial diseases in cultured fish has also increased. Microbiological research has been generally focused to detect the harmful intestinal bacteria, and the methods to control them. Very little research has been done to detect the beneficial bacteria, especially the lactic acid bacteria group and its applications. >> more info… |
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El-Shafai, S.A.A.M. (2004)
Nutrients valorisation via duckweed-based wastewater treatment and aquaculture >> more info…
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Graaf, G.J. de (2004)
Optimisation of the pond rearing of Nile tilapia (Oreochromis niloticus L.). The impact of stunting processes and recruitment control
Stunting is often considered as a major bottleneck for the pond rearing ofNiletilapia ( Oreochromis niloticus niloticus L.) and was a major topic in this study. Neonteny: the earlier breeding of tilapia in ponds takes place, but is not a bottleneck as with appropriate feeding levels the somatic growth is maintained. The study indicated that aggravation of the living conditions is not a major cause of the observed earlier breeding. >> more info… |
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Oostenbrugge, J.A.E. van (2003)
Uncertainty in daily catch rate in the light fisheries around Ambon and the Lease Islands: characterisation, causes and consequences
Fishermen experience variation in their daily catches that they cannot explain from their knowledge and experience. This uncertainty in daily catch rate is important in the life of fishermen and should be seen as a main characteristic of a fishery. This study tries to decrease the gap in knowledge on this subject by (1) characterising uncertainty in daily catch rate, (2) analysing the sources of this uncertainty and (3) outlining the consequences of uncertainty for the organisation of the fishery and its management. >> more info… |
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Braak, C.B.T. van de (2002)
Haemocytic defence in black tiger shrimp (Penaeus monodon)
Tropical shrimp culture is one of the fastest growing aquaculture sectors in the world. Since this production sector is highly affected by infectious pathogens, disease control is nowadays a priority. Effective prevention methods can be developed more efficiently when quantitative assays for the evaluation and monitoring of the health status of shrimp are available. >> more info… |
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Ruane, N.M. (2002)
Stress and stress disorders in a teleost fish, the common carp Cyprinus carpio L.
Unlike research using mammalian animal models such as rats or mice, experimental fish often come from wild or commercial sources, leading to a lack of well defined experimental animal models. Isogenic carp offer us a well defined fish model for physiological research. The aim of this thesis was to, therefore, investigate the physiological stress response of isogenic strains of carp. >> more info… |
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Ulloa Rojas, J.B. (2002)
Use of coffee pulp as feed ingredient for tilapia culture
This research focused on the feasibility of using coffee pulp (CoP) in diets for tilapia ( Oreochromis aureus ). First, a literature survey analyzed the limitations of CoP as an animal foodstuff (several antinutritional factors: ANF's, and high fibre contents), different ways to upgrade the CoP nutritional value and the maximal inclusion level of CoP in diets for ruminants, monogastric animals and fish. >> more info… |
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Viveiros, A.T.M. (2002)
Semen collection and preservation in African catfish, Clarias gariepinus
Stock improvement using quantitative and molecular genetics is an essential part of nowadays production of farm animals and fish. To achieve this in aquaculture, germplasm of both parental sexes should be obtained in a life-saving manner. In captivity, male African catfish, Clarias gariepinus , do not release semen under abdominal massage and have to be sacrificed to obtain sperm from the macerated testes. >> more info… |
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Alfaro Montoya, J. (2001)
Controlled reproduction of penaeid shrimp: a contribution to its improvement
This dissertation deals with controlled reproduction of penaeid shrimp. New knowledge about natural reproductive activity of Penaeus occidentalis in Gulf of Nicoya, Costa Rica, is presented. Since in vitro fertilization of open thelycum shrimp proved unsuccessful, a hypothesis is given to explain experimental results. In P. setiferus , the Male Reproductive Blackening Disease was studied, and bacterial infection was found to be associated with the male's condition. >> more info… |
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Grift, R.E. (2001)
How fish benefit from floodplain restoration along the lower River Rhine
The objectives of this study were to test the beneficial value of newly created secondary channels and reconnected oxbow lakes along the lower River Rhine for fish and to give advice on position, shape and character of future water bodies. These water bodies should contribute to the rebuilding of the population of rheophilic cyprinids that are endangered due to embankment and normalization of the Rhine. >> more info… |
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Jimenez-Montealegre, R.A. (2001)
Nitrogen transformations and fluxes in fish ponds: a modelling approach
Nitrogen is a key element in aquatic environments, and in Aquaculture it is an important pond management variable. In current aquaculture research two important goals are to maintain the water quality within the system, and to improve the retention of nutrients applied to the system in order to minimize the discharge. The principal objectives of this study were to integrate the information available of nitrogen processes in fish ponds into a predictive model, and to investigate further the nitrogen dynamics between the water, the sediments and the biota present in this systems. >> more info… |
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Ozorio, R. (2001)
Dietary L-carnitine and energy and lipid metabolism in African catfish (Clarias gariepinus) juveniles
As the lipid content of the diet increases so does the requirement for certain components involved in lipid metabolism. Carnitine is a normal constituent of animal tissues and plasma, which is required for the transport of long-chain fatty acids (LCFAs) to the site of oxidation. To avoid accumulation of lipids, supplementation of dietary carnitine may be used to stimulate fatty acid oxidation and to regulate lipolysis. Previous studies have demonstrated that responses to carnitine administration were ambiguous. >> more info… |
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Ul Azim, M.E. (2001)
The potential of periphyton-based aquaculture production systems >> more info… |
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Garcia Ortega, A. (1999)
Nutritional value of decapsulated cysts of Artemia and their use as protein source in experimental microdiets for fish larvae
Live food dependence and the lack of suitable artificial diets are major constraints for the expansion of the larviculture in many fish species. The low digestibility and nutritional quality of artificial diets are factors that might explain their failure as starter food for fish. In this thesis, physiological aspects related to the capacity for digestion of food by fish larvae were studied. In addition, the protein quality in decapsulated cysts and nauplii of Artemia was evaluated, and the feasibility of using cysts as protein source in microdiets for fish larvae was studied. African catfish Clarias gariepinus was the experimental species.>> more info… |
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Wudneh, T. (1998)
Biology and management of fish stocks in Bahir Dar Gulf, Lake Tana, Ethiopia.
The biology of the fish stocks of the major species in the Bahir Dar Gulf of Lake Tana, the largest lake in Ethiopia, has been studied based on data collected during August 1990 to September 1993. The distribution, reproduction patterns, growth and mortality dynamics and gillnet selectivity of these stocks are described. >> more info… |
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Bongers, A.B.J. (1997)
Development and application of genetically uniform strains of common carp (Cyprinus carpio L.)
In this thesis, the development of genetically uniform strains of common carp, Cyprinus carpio L. is described. As in research on mammals, the use of genetically uniform fish could increase the quality (replicability, reproducability and repeatability) of experiments. Inbreeding was done by gynogenetic and androgenetic reproduction. With these methods, fully homozygous. offspring are produced in only one generation. >> more info… |
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Conceiçâo, L.E.C. (1997)
Growth in early life stages of fishes: an explanatory model
Although fish larvae grow very fast, little is known about to which extent their metabolism and nutritional requirements differ from larger fish. Modelling can be a powerful too] to promote understanding and optimisation of growth in fish larvae. The main objective of this study was to develop an explanatory model that can simulate growth in fish larvae. The study was conducted in three steps, i.e., a design, an experimentation and a modelling step. >> more info… |
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Meer, M.B. van der (1997)
Feeds and feeding strategies for Colossoma macropomum (Cuvier 1818) fish growth as related to dietary protein.
Colossoma macropomum is an indigenous fish species from the Amazon region. The amino acid profile of its body protein proved to be similar to that of other fish species. Soya meal and fish meal have, based on their amino acid profiles, a comparable protein quality. This hypothesis was confirmed in a feeding trial. As soya meal is less palatable than fish meal, more soya in the diet tends to decrease feed uptake and growth rate, but increases protein utilization efficiency. >> more info… |
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Heijden, M.H.T. van der (1996)
Impact of antibacterial drugs on the health of European eel
Application of antibacterial drugs plays an important role in the control of bacterial diseases in intensive fish culture. However, since the scientific basis for the use of these drugs is yet inadequate, there is a growing concern about the safety of fish medication for the consumer, the environment and the target animals. This led to the research presented in this thesis, which is focused on the influence of the antibacterial drug flumequine on the defence system of European eel (Anguilla anguilla L., 1758). >> more info… |
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Piet, G.J. (1996)
On the ecology of a tropical fish community.
Sri Lanka has more than 12.000 artificial reservoirs and no natural lakes as is true for many other areas in SE Asia. These reservoirs cover a total surface area of around 175.000 ha. They are shallow with maximum depths often less than 5 m and exhibit considerable fluctuations in water level. In general the fish production, estimated from commercial catches, is high in these reservoirs, but lower than would be expected on the basis of the high primary production. >> more info… |