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1.
Increased aquaculture production has raised concerns about managing protocols to safeguard the welfare of farmed fish, as
consumers demand responsible aquaculture practices to provide ‘welfare friendly’ products. Feeding is one of the largest production
cost in a fish farm and can be one of the biggest stressors for fish. Under farming conditions, fish are challenged with artificial
diets and feeding regimes, and inadequate feeding conditions cause stress, alteration of normal behavioural patterns, poor
performance and eventually diseases and death, which are by no means acceptable neither economically nor ethically. This review
aims to highlight the impact of feeding rhythms and feeding time upon physiological and behavioural welfare indicators, which
show circadian rhythms as well. Therefore, all these variables should be considered when designing feeding strategies in farming
conditions and assessing the welfare state of cultured fish. 相似文献
2.
Morphological comparison of wild,farmed and hybrid specimens of two South American silversides,Odontesthes bonariensis and Odontesthes hatcheri 
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下载免费PDF全文 Sonia Alejandra Crichigno Ricardo Shohei Hattori Carlos Augusto Strüssmann Víctor Cussac 《Aquaculture Research》2016,47(6):1797-1808
In this study, body shape of hybrid and presumptive introgressed South American silversides was studied. Body shape of O. bonariensis and O. hatcheri from wild populations and farmed stocks was compared to provide basic information on the effects of fish farming on morphometric parameters. Subsequently, wild presumptive introgressed individuals and artificially hybridized farmed individuals were morphologically analysed to assess the effects of hybridization on the same parameters. Most farmed purebred individuals were shorter and higher than their wild counterparts, which is probably due to the favourable growth conditions compared to the wild habitat. However, the results evidenced that purebred individuals were more slender than both hybrid (farmed) fish and introgressed (wild) fish. Further studies on the growth performance of hybrid Odontesthes will be required in order to assess whether the combination of hybridization and sterilization could produce, under farming conditions, growth performances which satisfy the requirements of aquaculture. 相似文献
3.
Kitojo Wetengere 《Aquaculture International》2011,19(1):33-49
Intensification of farm technologies has shown high potential in improving farm production and enhancing rural food and income
security. Intensification, however, is commodity-specific with high-value crops intensively produced. Farmed fish is one of
the high-value crops introduced in the study area to meet the above ends. The problem, however, is that the level of intensifying
fish farming technology has been very low leading to discouraging results. A study was conducted in Morogoro and Dar es Salaam
Regions, Tanzania, to identify socio-economic factors that influence the intensification of fish farming technology. Data
were collected from 234 respondents randomly sampled from 25 selected villages and were analyzed using multinomial logistic
regression model. Results indicated that age, extension education, profitability, marketability, risk, palatability and easiness
to obtain farmed fish were significant in explaining the intensification of fish farming technology. Three recommendations
emerge from this finding. First, there is need to provide extension education to the practicing farmers on various aspects
of fish farming. The probability of intensifying fish farming is higher for knowledgeable farmers. Second, technology developers
should strive to reduce the risk of farming fish and improve the profitability and marketability of farmed fish. Finally,
any analysis focusing on intensification of a fish farming technology should not confine itself to agronomic and socio-economic
characteristics but should also encompass food characteristics of the technology. Food variables such as palatability and
easiness to obtain farmed fish have been shown to influence the intensification of fish farming technology. 相似文献
4.
The most controversial environmental problems in commercial salmon farming are the negative effects of sea lice (Lepeoptheirus salmonis, Caligus spp.), the genetic introgression of farmed salmon in wild populations, nutrient waste load and the emission of potentially toxic waste to coastal waters. Moving production from sea cages to land-based facilities, offshore farming or marine closed containment systems (CCS) are suggested as possible ways to solve these problems. However, there are few published studies on production capacity and fish welfare in such systems. The main aim of this study was to describe growth rates, mortality rates and mortality causes in the commercial-scale production of Atlantic salmon (Salmo salar) post-smolts in CCS from sea transfer until the size of 1000 g. From October 2014 to May 2017, we recorded growth rates, feed use, mortality and mortality causes during 23 CCS production cycles, including 18 CCS periods with off-season smolt (S0) and 5 CCS periods with one-year smolt (S1). The mean (SD) growth rate, thermal growth coefficient (TGC), for all 23 CCS was 3.03 (0.34), with no difference between cages with S1 (n = 5) and cages with S0 (n = 1 8). Cumulative mortality three months after sea transfer (CM3mo) was 2.6 %, while cumulated mortality throughout the total trial period (CMtotal, mean number of days = 159) was 3.6 %. Both CM3mo and CMtotal were higher in S1 groups than in S0 groups. Mean (SD) feed conversion ratio in CCS with S0 (n = 18) was 1.11 (0.07). The two main mortality causes were ‘Ulcers and fin rot’ (S1 and S0) and ‘Failed smolt’ (S1), accounting for 36.1 % and 19.3 % of the total mortality, respectively. Water flow, oxygen saturation and other water quality parameters were within safe limits for fish health and welfare. 相似文献
5.
Anaesthesia of farmed fish: implications for welfare 总被引：1，自引：0，他引：1
During their life cycle as farmed animals, there are several situations in which fish are subjected to handling and confinement.
Netting, weighing, sorting, vaccination, transport and, at the end, slaughter are frequent events under farming conditions.
As research subjects, fish may also undergo surgical procedures that range from tagging, sampling and small incisions to invasive
procedures. In these situations, treatment with anaesthetic agents may be necessary in order to ensure the welfare of the
fish. The main objective of this paper is to review our knowledge of the effects of anaesthetic agents in farmed fish and
their possible implications for welfare. As wide variations in response to anaesthesia have been observed both between and
within species, special attention has been paid to the importance of secondary factors such as body weight, water temperature
and acute stress. In this review, we have limited ourselves to the anaesthetic agents such as benzocaine, metacaine (MS-222),
metomidate hydrochloride, isoeugenol, 2-phenoxyethanol and quinaldine. Anaesthetic protocols of fish usually refer to one
single agent, whereas protocols of human and veterinary medicine cover combinations of several drugs, each contributing to
the effects needed in the anaesthesia. As stress prior to anaesthesia may result in abnormal reactions, pre-anaesthetic sedation
is regularly used in order to reduce or avoid stress and is an integral part of the veterinary protocols of higher vertebrates.
Furthermore, the anaesthetic agents that are used in order to obtain general anaesthesia are combined with analgesic agents
that target nociception. The increased use of such combinations in fish is therefore included as a special section. Anaesthetic
agents are widely used to avoid stress during various farming procedures. While several studies report that anaesthetics are
effective in reducing the stress associated with confinement and handling, there are indications that anaesthesia may in itself
induce a stress response, measured by elevated levels of cortisol. MS-222 has been reported to elicit high cortisol release
rates immediately following exposure, while benzocaine causes a bimodal response. Metomidate has an inhibitory effect on cortisol
in fish and seems to induce the lowest release of cortisol of the agents reported in the literature. Compared to what is observed
following severe stressors such as handling and confinement, the amount of cortisol released in response to anaesthesia appears
to be low but may represent an extra load under otherwise stressful circumstances. Furthermore, anaesthetics may cause secondary
adverse reactions such as acidosis and osmotic stress due to respiratory arrest and insufficient exchange of gas and ions
between the blood and the water. All in all, anaesthetics may reduce stress and thereby improve welfare but can also have
unwanted side effects that reduce the welfare of the fish and should therefore always be used with caution. Finally, on the
basis of the data reported in the literature and our own experience, we recommend that anaesthetic protocols should always
be tested on a few fish under prevailing conditions in order to ensure an adequate depth of anaesthesia. This recommendation
applies whether a single agent or a combination of agents is used, although it appears that protocols comprising combinations
of agents provide wider safety margins. The analgesic effects of currently used agents, in spite of their proven local effects,
are currently being debated as the agents are administrated to fish via inhalation rather than locally at the target site.
We therefore recommend that all protocols of procedures requiring general anaesthesia should be complemented by administration
of agents with analgesic effect at the site of tissue trauma. 相似文献
6.
Strategies and technologies in offshore farming 总被引：1，自引：0，他引：1
A more restrictive attitude to inshore farming, in addition to positive biological findings among offshore farmed fish, have increased the demand for suitable offshore fish farming cages/systems.
To develop such a cage/system, the requirements of the fish, the fish farmer, the insurance companies, the authorities and the moorings must be considered. The existing offshore concepts can be classified into: (1) simple flexible one-net bag cages; (2) integrated stiff semi-submersible one-net bag constructions; (3) simple stiff poly-net bag cages; (4) integrated stiff poly-net bag constructions; (5) submersible and submerged cages. An example from each group is described.
The Bridgestone cage and the Farmocean system, the only offshore concepts that have been in commercial use for some years, are compared with respect to strength and management. The other concepts are evaluated in various parts.
A suitable offshore concept should, in general, consist of a stable, strong and safe platform that should be easy and safe to tow, moor and board. It should allow a proper attachment of the net bag (preferably round, 15 m deep and 5000 m3 in volume), and guarantee its strength and shape during all weather conditions. The fish should be fed by means of a computer-controlled automatic feeder.
Faster growth, lowered mortality and reduced visceral fat content are reported among offshore farmed fish compared with those farmed inshore. A lower degree of self-pollution will also be a consequence of moving larger and deeper cages/systems offshore.
The tentative rules for the type approval of floating fish farming units that have been presented by “Det norske Veritas” (DnV) in Norway will be positive for the fish farming business if it starts to be valid and cover the rest of the fish farming countries.
Despite the higher investment required for the offshore cages/systems, it has been indicated that there is a better economic result and that the cost of producing 1 kg of fish is lower than in conventional fish farms.
As the single-net bag concept represents a lower risk for the fish farmer, insurance company and veterinary authority, it will probably be the preferred concept. 相似文献
7.
I. K. Berrill T. Cooper C. M. MacIntyre T. Ellis T. G. Knowles E. K. M. Jones J. F. Turnbull 《Fish physiology and biochemistry》2012,38(1):219-229
The welfare of farmed fish has attracted attention in recent years, which has resulted in notable changes within the aquaculture
industry. However, a lack of communication between stakeholders and opposing ethical views are perceived as barriers to achieving
consensus on how to improve farmed fish welfare. To address these issues, we developed an interactive approach that could
be used during stakeholder meetings to (1) improve communication between different stakeholder groups, (2) build consensus
on priorities for farmed fish welfare and (3) establish mechanisms to address welfare priorities. We then applied this approach
during a meeting of stakeholders to identify current and future priorities for farmed fish welfare in the UK. During the meeting
in the UK, stakeholders initially identified 32 areas that they felt were in need of development for future improvements in
farmed fish welfare. These were further refined via peer review and discussion to the seven most important “priority” areas.
Establishing a “better understanding of what good fish welfare is” emerged as the highest priority area for farmed fish welfare. The second highest priority area was “the need for welfare monitoring and documentation systems”, with mortality recording proposed as an example. The other five priority areas were “[improved understanding of] the role of genetic selection in producing fish suited to the farming environment”, “a need for integration and application of behavioural and physiological measures”, “the need for a more liberal regime in Europe for introducing new medicines”, “a need to address the issues of training existing and new workers within the industry”, and “ensuring best practise in aquaculture is followed by individual businesses”. Feedback from attendees, and the meeting outputs, indicated that the approach had been successful in improving communication
between stakeholders and in achieving consensus on the priorities for farmed fish welfare. The approach therefore proved highly
beneficial for future improvements in fish welfare in the UK. 相似文献
8.
Samantha Bui Frode Oppedal Velimir Nola Luke T. Barrett 《Journal of fish diseases》2020,43(6):697-706
Problematic sea lice infestations on farmed Atlantic salmon (Salmo salar) have motivated extensive research and development into new methods to prevent, monitor and control sea lice. Most of these technologies require detailed information on the behaviour, spatial distribution and demography of lice on host fish. This study investigated how salmon lice (Lepeophtheirus salmonis) infestation density varies across the host's surface under sea cage farming conditions. Lice abundance, demography and attachment location were tracked over time, with repeated sampling of 300 individually tagged salmon across three replicate experimental sea cages. The data reveal clear differences in attachment locations according to sex and stage, but with an overall preference for the dorsal surface among mobile stages—dorsal head for adult females and dorsal-posterior section for males and pre-adults. Total lice abundance was highly variable between repeated measures of individual fish, consistent with frequent host-switching or mortality. Total lice numbers also declined between sampling dates, likely due to handling, with lost mobile lice being almost exclusively adult males. As the distribution of sea lice on hosts is likely determined by numerous factors, future image-based automated detection systems should be validated in settings that reflect the complex host–parasite interactions that occur in open farming systems. 相似文献
9.
Fish welfare at harvest is easily compromised by poor choice of handling and slaughter methods, lack of attention to detail
and by unnecessary adherence to fish farming traditions. The harvest process comprises fasting the fish to empty the gut,
crowding the fish, gathering and moving the fish using brails, fish pumps, and sometimes also road or boat transport and finally
stunning and killing the fish. The harvesting processes commonly used for bass, bream, carp, catfish, cod, eel, halibut, pangasius,
salmon, tilapia, trout, tuna and turbot are outlined. These harvesting processes are discussed; the consequences for fish
welfare identified and practical tests which can be made at the harvest site highlighted. Welfare at harvest for the majority
of farmed fish species can be improved by adopting and adapting existing procedures already known to be beneficial for fish
welfare through their use in other fish farming systems or with other species. It is seldom necessary to develop completely
new concepts or methods. 相似文献
10.
The government of Kenya encourages aquaculture development by offering credit facilities through the government agricultural
finance institution, Agriculture Finance Corporation. Nevertheless, the level of credit use in fish farming is very low. Access
to credit is among several factors that affect farmers’ decision of whether to use particular technology or services. The
study examined factors that affected the decision of fish farmers in Kenya to utilize credit facilities in fish production
using a probit model. The analysis suggests that farmers in the Western province will have a 19% more probability of using
credit facilities for their fish farming operations than farmers from the other provinces such as the Rift Valley, Central,
and the Eastern province. The effect of tilapia sales on the probability of credit use by fish farmers is more than three
times that of catfish sales. Total pond acreage owned by fish farmers had a positive effect on credit use but the effect was
very small and negligible. The level of fish farmers’ use of credit facilities is very low, and there is probably the need
to educate farmers on credit use and for the government agricultural lending agency and other commercial agricultural lenders
to invest in this enterprise. Kenyan lending institutions have financed traditional agricultural enterprises, and with the
growing production of farmed fish, more research is needed to document the aquaculture business model to assist in assessing
the profitability potential in aquaculture. 相似文献
11.
R. Gornati S. Gualdoni R. Cavaliere G. Terova M. Saroglia G. Bernardini 《Aquaculture International》2005,13(1-2):51-55
The issue of animal welfare in aquaculture is of growing interest and there is an increasing consumer demand for documentation of safe and ethically defendable food production. In this context, we have looked for molecular markers among those genes whose expression is modified by the different farming conditions. We have compared gene expression of sea bass farmed at different population densities by differential display, and we have obtained six bands differentially expressed whose sequences have been deposited in the public databases; two of them were suppressed by high population density, while four were induced by the treatment. These genes can be used as biomarkers, and together with a panel of stress-related genes of sea bass (D. labrax) that we have already obtained, could allow the rapid diagnosis of the welfare status of a fish using RT-PCR. We are certain that the new molecular techniques will find their place in the everyday management of fish farming. On the other hand, we are also aware that the scarcity of genomic resources for some fish species, in spite of their economical interest, will retard the beneficial effects that modern biotechnology could bring to aquaculture industry. Therefore, an effort should be made to reduce, as far genomic resources are concerned, the gap that separates farmed species from model organisms such as Danio rerio and Fugu rubripes. 相似文献
12.
The study assessed the value chain of farmed tilapia in Ghana. A survey conducted in 2012 provided data on key actors, flow of products and information, costs and margins, and relationship among actors. The study showed that all key actors in the value chain: input suppliers; fish farmers; traders; and food services had positive margins except fish farmers. Input suppliers accrued most of the margins generated along the chain. The performance of chain actors was assessed using a factor evaluation matrix, which showed that product offering may be the strength at each stage of the value chain. The efficiency and profitability of tilapia value chain in Ghana can be improved by having well-defined payment transaction with customers, persistent relationships with customers, and good information management such as keeping good records on costs and revenues. Fish farming could be more profitable if farmers reduced their variable costs, priced their fish using a cost plus or percentage markup approach, and adopted target marketing. 相似文献
13.
Lydia M. Vasilyeva Ashraf. I. Gh. Elhetawy Natalia V. Sudakova Svetlana S. Astafyeva 《Aquaculture Research》2019,50(4):979-993
Since natural sturgeon populations have drastically declined, aquaculture of these valuable fish is important to meet the ever‐increasing demand for meat and caviar, thereby reducing the pressure on natural sturgeon resources. There are two directions in sturgeon aquaculture: controlled propagation for release and commercial farming. The controlled propagation supports the conservation of natural fish populations, while the commercial cultivation of sturgeons supplies the needs of the consumer market with the delicacy production of caviar (mainly). This review deals with the current status of the controlled propagation and stocking in the Volga‐Caspian basin and the commercial farming of sturgeons in Russia. The article also investigates the management of farmed broodstocks of sturgeons, which are used for obtaining seedlings and caviar. It is for sure that the active and continuous development of the two directions of sturgeon aquaculture will allow preserving these unique ancient fish on our planet until natural populations can be re‐established by self‐sustaining populations. 相似文献
14.
Rosalba Gornati Genziana Terova Davide Vigetti Mariangela Prati Marco Saroglia Giovanni Bernardini 《Aquaculture (Amsterdam, Netherlands)》2004,230(1-4):229-239
The issue of animal welfare in aquaculture is growing of interest and there is an increasing consumer demand for documentation of safe and ethically defendable food production. In this context, we have looked for molecular markers among those genes whose expression results modified by the different farming conditions. We have compared gene expression of seabass farmed at different population densities by differential display. We have obtained six bands differentially expressed whose sequences we have deposited in the public databases; two of them resulted suppressed by high population density, while four were induced by the treatment. Population density has, therefore, an effect at gene level by repressing or enhancing the expression of different genes. These genes can be used as biomarkers to rapidly detect, by polymerase chain reaction (PCR), the occurred exposure of the fish to the stressor.
We are certain that the new molecular techniques will find their place in the everyday management of fish farming; on the other hand, we are also aware that the scarcity of the genomic resources for some fish species, in spite of their economical interest, will retard the beneficial effects that modern biotechnology could bring to aquaculture industry. Therefore, an effort should be made to reduce, as far as it concerns genomics resources, the gap that separates farming species from “model organisms”. 相似文献
15.
This study explores the ecological and economic impacts of interactions between escaped farmed and wild Atlantic salmon (Salmo salar, Salmonidae) over generations. An age‐ and stage‐structured bioeconomic model is developed. The biological part of the model includes age‐specific life‐history traits such as survival rates, fecundity and spawning successes for wild and escaped farmed salmon, as well as their hybrids, while the economic part takes account of use and non‐use values of fish stock. The model is simulated under three scenarios using data from the Atlantic salmon fishery and salmon farming in Norway. The social welfare is derived from harvest and wild salmon while the economic benefits of fishing comprise both sea and river fisheries. The results reveal that the wild salmon stock is gradually replaced by salmon with farmed origin, while the total social welfare and economic benefit decline, although not at the same rate as the wild salmon stock. 相似文献
16.
17.
Current status of parasitic ciliates Chilodonella spp. (Phyllopharyngea: Chilodonellidae) in freshwater fish aquaculture 下载免费PDF全文
下载免费PDF全文 《Journal of fish diseases》2017,40(5):703-715
Freshwater fish farming contributes to more than two‐thirds of global aquaculture production. Parasitic ciliates are one of the largest causes of production loss in freshwater farmed fishes, with species from the genus Chilodonella being particularly problematic. While Chilodonella spp. include ‘free‐living’ fauna, some species are involved in mortality events of fish, particularly in high‐density aquaculture. Indeed, chilodonellosis causes major productivity losses in over 16 species of farmed freshwater fishes in more than 14 countries. Traditionally, Chilodonella species are identified based on morphological features; however, the genus comprises yet uncharacterized cryptic species, which indicates the necessity for molecular diagnostic methods. This review synthesizes current knowledge on the biology, ecology and geographic distribution of harmful Chilodonella spp. and examines pathological signs, diagnostic methods and treatments. Recent advances in molecular diagnostics and the ability to culture Chilodonella spp. in vitro will enable the development of preventative management practices and sustained freshwater fish aquaculture production. 相似文献
18.
Pablo Emilio Cruz‐Casallas Víctor Mauricio Medina‐Robles Yohana María Velasco‐Santamaría 《Aquaculture Research》2011,42(6):823-831
In Colombia and the rest of the world, the decrease in capture fisheries production has turned the aquaculture into an alternative source of protein for the populations food security as well as an important productive activity, generating employment and income for the rural communities. The Colombian pisciculture is based on red Tilapia Oreochromis sp. (Linnaeus), Rainbow trout Oncorhynchus mykiss (Walbaum) and cachama blanca Piaractus brachypomus (Cuvier), which currently represent around 96% of the total national production. The remaining 4% comes from other farmed species such as bocachico Prochilodus magdalenae (Steindachner), carp Cyprinus carpio (Linnaeus) and yamúBrycon amazonicus (Spix & Agassiz). From the three main fish species, cachama blanca is the only native species, which has shown excellent performance in pond farming due to its rusticity, omnivorous habits, docility, meat quality, food conversion and disease resistance. The limited offer of Colombian fish farmed species determines its currently low competitiveness and restricted impact on the international markets; thus making necessary to explore the potential of new fish species in order to introduce them to the pisciculture system and to expand the range of fish farming species. A good alternative is the introduction of native catfish, which have great potential for fish farming activity. 相似文献
19.
Segner H Sundh H Buchmann K Douxfils J Sundell KS Mathieu C Ruane N Jutfelt F Toften H Vaughan L 《Fish physiology and biochemistry》2012,38(1):85-105
This brief review focuses on health and biological function as cornerstones of fish welfare. From the function-based point
of view, good welfare is reflected in the ability of the animal to cope with infectious and non-infectious stressors, thereby
maintaining homeostasis and good health, whereas stressful husbandry conditions and protracted suffering will lead to the
loss of the coping ability and, thus, to impaired health. In the first part of the review, the physiological processes through
which stressful husbandry conditions modulate health of farmed fish are examined. If fish are subjected to unfavourable husbandry
conditions, the resulting disruption of internal homeostasis necessitates energy-demanding physiological adjustments (allostasis/acclimation).
The ensuing energy drain leads to trade-offs with other energy-demanding processes such as the functioning of the primary
epithelial barriers (gut, skin, gills) and the immune system. Understanding of the relation between husbandry conditions,
allostatic responses and fish health provides the basis for the second theme developed in this review, the potential use of
biological function and health parameters as operational welfare indicators (OWIs). Advantages of function- and health-related
parameters are that they are relatively straightforward to recognize and to measure and are routinely monitored in most aquaculture
units, thereby providing feasible tools to assess fish welfare under practical farming conditions. As the efforts to improve
fish welfare and environmental sustainability lead to increasingly diverse solutions, in particular integrated production,
it is imperative that we have objective OWIs to compare with other production forms, such as high-density aquaculture. However,
to receive the necessary acceptance for legislation, more robust scientific backing of the health- and function-related OWIs
is urgently needed. 相似文献
20.
Because of their rapid autolysis and post mortem contamination, the examination of dead seapen salmon has been considered of limited value for investigating disease in farmed salmon. Marine anaemia is a recently described plasmacytoid leukemia of farmed salmon that is diagnosed primarily by histological findings. The objectives of this study were to determine if marine anaemia could be reliably diagnosed in dead fish under commercial conditions and to identify the factors that affect the quality of data that are derived from mortality surveys. Surface moribund fish and dead salmon were recovered from four adjacent pens on 31 farm visits to commercial salmon farms over a 6-month period. Mortality surveys provided six times as many fish for gross pathological diagnosis and three times as many fish for reliable histological diagnosis of marine anaemia than did surveys of surface moribund salmon. The interval between recovery of dead fish from a pen most strongly influenced the quality of information derived from the mortality surveys. Mortality surveys proved to be more sensitive to finding the disease than did surface morbidity surveys. The results demonstrated that mortality surveys can provide reliable information, which can generate new insights not only into the impact and epidemiology of marine anaemia, but also for other fatal diseases of seapen salmon. 相似文献