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1.
Sha Sha Julie Insignares Santos Frank Asche 《Aquaculture Economics & Management (Blackwell Science)》2015,19(3):336-352
This article evaluates the effects of extensive media coverage of a study published in 2004 regarding the presence of polychlorinated biphenyls (PCBs) and other organic contaminates in farmed salmon on U.S. import demand for fresh farmed salmon. The study indicated that levels of PCBs differed according to source, with highest PCB levels found in salmon from Northern Europe and lowest in those from Chile. Using a newspaper article index as a proxy for information, a two-stage demand model is estimated. In the first stage, total U.S. import demand for fresh farmed salmon is estimated to determine the overall effect of the information, while the second stage determines if there were any significant changes in market shares of source countries. Results indicate that imports declined by approximately one-third of what would have been in the absence of the PCB media stories during 2004–2006, and that some changes in exporters’ market shares occurred. Health implications for U.S. seafood consumers are discussed. 相似文献
2.
Treasurer JW 《Journal of fish diseases》2012,35(8):555-562
There have been several reported studies of wrasse health but none of these has shown transmission of wrasse diseases when stocked with farmed Atlantic salmon. Most of the studies have focussed on bacterial and parasite issues, including treatment of bacterial diseases with antibiotics and vaccination of wrasse. Classical and atypical furunculosis have been reported in wrasse following stress, and wrasse have been susceptible to vibrio infection. Further study is required on the vaccination of wrasse for furunculosis with latent carrier status to maximize survival. There are studies on viral diseases such as infectious pancreatic necrosis, infectious salmon anaemia and pancreas disease and although these did not give any undue concern for salmon health, there is also scope for further study in this area. Resident parasite communities of wrasse are largely host-specific and do not appear to be a threat to salmon. Given that wrasse have not, to date, been a vector of disease in salmon, attention should be placed on maintaining best practice in cohabiting wrasse with salmon. Other issues that should be addressed are good welfare of wrasse in pens and identifying measures of this, the identification of losses of wrasse in pens, being alert to potential emerging diseases through health screening of mortalities and assessing the risks associated with carrying forward wrasse from one salmon production cycle to the next. Issues of exploitation by fishing on wild wrasse stocks and improved biosecurity may be addressed by the increased movement by the industry to the stocking of farmed wrasse. 相似文献
3.
Murray A. Rudd Nathan Pelletier Peter Tyedmers 《Aquaculture Economics & Management (Blackwell Science)》2013,17(1):18-45
The goal of this research was to shed light on the trade-offs that salmon consumers make between five types of production and health attributes of farmed salmon. In Canada, the major southern Ontario market cleaved into five distinct consumer segments that varied according to age and income, ‘tastes’, and threat perceptions. There was strong consumer aversion to increased levels of PCBs, even when increased contamination levels were well within Health Canada guidelines. Both contaminant avoidance and polyunsaturated fatty acid health benefits were generally more important to consumers than improved environmental performance in salmon farming production practices. The strong consumer preferences for reduced levels of PCBs in salmon flesh suggest that there could be a substantial market premium for farmed salmon produced using reduced levels of fish meal and fish oils in salmon feed. This could, by association, increase the environmental sustainability of salmon farming. 相似文献
4.
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
5.
Migratory behaviour of adult wild and escaped farmed Atlantic salmon, Salmo salar L., before, during and after spawning in a Norwegian river 总被引：1，自引：0，他引：1
The migratory behaviour of adult wild and escaped farmed Atlantic salmon, Salmo salar L., before, during after spawning in the River Namsen, Norway, was analysed using radio telemetry. The fish were caught, radio tagged and released into the fjord between 7 and 25 km from the river mouth. A significantly higher proportion of wild (74%) than farmed (43%) salmon was subsequently recorded in the river. Wild salmon (33%) were more frequently captured in the sea and in rivers than farmed salmon (14%). The migration speed from release to passing a data logger 11 km upstream from the river mouth was not significantly different between wild (20.6 km day?1) and farmed (19.8 km day?1) salmon. Wild salmon tagged when water flow in the river was increasing had a significantly higher migration speed than wild salmon tagged when water flow was decreasing. This was not true for farmed salmon. Farmed salmon were distributed significantly higher up the river than wild salmon during spawning, although both types of fish were found together in spawning areas. Thus, there was no geographical isolation to prevent spawning between wild and escaped farmed salmon. Farmed salmon had significantly more and longer up- and downstream movements than wild salmon during the spawning period. Unlike farmed salmon, the number of riverine movements by wild salmon increased significantly when variation in water flow increased. A smaller proportion of wild (9%) than farmed (77%) salmon survived through the winter after spawning. 相似文献
6.
Arteriosclerosis in the ventral aorta and epicarditis in the bulbus arteriosus of Atlantic salmon (Salmo salar L) 
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下载免费PDF全文 A S Dalum K H Kristthorsdottir D J Griffiths K Bjørklund T T Poppe 《Journal of fish diseases》2017,40(6):797-809
Spontaneous mortality of seemingly healthy, farmed Atlantic salmon (Salmo salar L) is an increasing problem in Norwegian aquaculture. In this study, we present a morphological study of the previously undescribed syndrome of arteriosclerosis of the ventral aorta and epicarditis of the adjacent bulbus arteriosus found in farmed Atlantic salmon, with wild‐captured fish as a control group. Both the ventral aorta and epicardium are vital for correct arterial compliance and vascular resistance in the respiratory capillaries of the gills. We discuss the possible implications of ventral aorta arteriosclerosis and epicarditis for blood vascular health and in particular for the increasing frequency of spontaneous gill bleeding in farmed salmon. As both these conditions primarily occur in farmed salmon, we suggest that they should be considered pathological. 相似文献
7.
The recent glut of both wild and farmed salmon in world markets has forced producers to become aware of the need to expand their marketing efforts to ensure that demand is not outpaced by supply resulting in a further decline in prices. Japan has been a major market for wild salmon, particularly sockeye salmon from North America, since the introduction of the 200 mile Exclusive Economic Zone. As farmed supplies have continued to increase, exporters such as Norway and Chile have turned their attention to this market as well. Up until now, most of the farmed salmon exported to Japan has been targeted to the restaurant market. If exporters wish to expand their market in Japan, they may focus also on the retail market. Prior to any assessment of the potential of the retail market for fresh farmed salmon, it is useful to understand the role that salmon plays in Japanese household seafood consumption.
This paper examines household consumption patterns of salmon in Japan. An econometric model is presented which estimates household demand for fresh and salted salmon focusing specifically on the effects of seasonality, regional location, and prices of other seafood products. Two systems of demand equations, one for each of two regions of Japan, are specified and estimated using monthly data on prices and expenditures to capture the effects on household demand for 12 seafood products. Results indicate that seasonality plays a significant role in the demand for many seafood products, particularly fresh and salted salmon. In addition, these seasonal effects are not necessarily the same between regions of Japan. Salmon competes with different seafood products during different times of the year. A rich variety of factors should be considered when marketing fresh aquacultured salmon in the Japanese retail market. 相似文献
This paper examines household consumption patterns of salmon in Japan. An econometric model is presented which estimates household demand for fresh and salted salmon focusing specifically on the effects of seasonality, regional location, and prices of other seafood products. Two systems of demand equations, one for each of two regions of Japan, are specified and estimated using monthly data on prices and expenditures to capture the effects on household demand for 12 seafood products. Results indicate that seasonality plays a significant role in the demand for many seafood products, particularly fresh and salted salmon. In addition, these seasonal effects are not necessarily the same between regions of Japan. Salmon competes with different seafood products during different times of the year. A rich variety of factors should be considered when marketing fresh aquacultured salmon in the Japanese retail market. 相似文献
8.
Farmed Atlantic salmon, Salmo salar, frequently escape from the aquaculture industry and interact with wild populations. The impact of these interactions on the wild populations will depend, in part, on differences in their performances. This study compared the swimming and cardiac performance of farmed salmon (Aquagen) with their founder population from the River Namsen both before and after gamete stripping. Cardiac output (CO), heart rate (HR), and stroke volume (SV), which were measured by placing Doppler flow probes around the ventral aorta of the fish, increased with exercise, but the response did not significantly differ between farmed and wild salmon. Similarly, the swimming performance of wild salmon never significantly differed from the farmed salmon. The overall similarity in swimming and cardiac performance between farmed and wild Atlantic salmon observed in the present study suggests that cultured salmon may have the ability to be competitive with the wild salmon in native waters. 相似文献
9.
The migration patterns of wild and released farmed Atlantic salmon, Salmo salar L., were studied by radio-telemetry during migration from entering a river to after spawning. The wild salmon were caught during return migration in bagnets and the farmed salmon were produced in a near by fish farm. Both groups were tagged and released at sea near the river mouth of the River Alta, North Norway. A pronounced individual variation in migration pattern was observed. No significant differences was found between wild and farmed salmon in the distance from entering the river mouth to the place of the first stop (recorded in the same pool for 5 days or longer) and the days from entering the river mouth to arrival at the first stop. For both wild and farmed salmon, mean migration speed was 2.6 km day1, varying from 0.4 to 11.0 km day-1. A larger proportion of farmed salmon distributed to the upper part of the river at spawning; mean distances from the river mouth were 30.1 and 19.1 km. respectively. Farmed salmon spent a significantly longer time from entering the river to reaching the area occupied during spawning. 相似文献
10.
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
11.
Abstract. To estimate the proportion of escaped fanned Atlantic salmon. Salmo salar L., at the feeding grounds in the north-east Atlantic Ocean, samples of salmon caught with long-lines north of the Faroe Islands were examined. Identification of reared fish was carried out using scale analysis. The proportion of fanned fish was estimated to range from 25 to 48% in the different samples, suggesting that high numbers of escaped farmed salmon occur in the Norwegian Sea. The farmed fish were significantly smaller in size than the wild salmon. Although it is suggested that most of the farmed fish are of Norwegian origin, farmed fish of Scottish, Faroese and Irish origin are also believed to be present. If not accounted for, high numbers of reared salmon in fisheries and stocks will seriously affect the assessments of fisheries and stocks of wild salmon. 相似文献
12.
P. Laffaille 《Ecology of Freshwater Fish》2011,20(1):67-73
Laffaille P. Impact of stocked Atlantic salmon (Salmo salar L.) on habitat use by the wild population. Ecology of Freshwater Fish 2011: 20: 67–73. © 2010 John Wiley & Sons A/S Abstract – We investigated the summer habitat occupied by populations of young‐of‐the‐year wild and stocked (farmed populations released into the native range) Atlantic salmon under allopatric and sympatric conditions. Under allopatric conditions, farmed and wild salmon occupied habitats with the same characteristics. The salmon preferentially occupied the riffle areas. However, under sympatric conditions, the fish occupied meso‐ and micro‐habitats with different characteristics. Wild salmon avoided habitats used by farmed salmon and preferred glide areas with considerable vegetation cover. This study suggests that differences in the pattern of habitats used by young Atlantic salmon were both size‐ and origin‐dependent and may result from intra‐species competition between farmed and wild populations. Given that stocking with farmed Atlantic salmon is carried out intensively to enhance recreational angling or to conserve salmon populations, this study warns that this can have a negative impact on the extant wild Atlantic salmon population. 相似文献
13.
Jon Olaf Olaussen Yajie Liu 《Aquaculture Economics & Management (Blackwell Science)》2013,17(4):245-261
This article explores to what extent escaped farmed salmon from fish farms affect the willingness-to-pay for recreational fishing of Atlantic salmon in Norwegian rivers. This is a first attempt to explore the economic consequences of escaped farmed species in terms of the anglers’ willingness-to-pay for fishing permits working through the relationship between the price of fishing permits and the share of escaped farmed salmon. The empirical analysis is based on the results from a contingent valuation survey conducted in Norway. It is found that the presence of escaped farmed salmon in Norwegian rivers may have severe economic consequences on the willingness-to-pay for recreational fishing with a reduction of up to 85% compared to a situation with a ‘pure’ wild salmon stock. 相似文献
14.
Wild salmonids and farmed salmon can both be sources of Lepeophtheirus salmonis (Krøyer, 1838) larvae . Farmed salmon smolts free of L. salmonis infections are stocked in sea cages and may subsequently contract L. salmonis infections, probably from wild fish. The contribution of gravid L. salmonis at Atlantic salmon, Salmo salar L., farms to populations of L. salmonis larvae in the water column has in the past been based on estimated parameters, such as louse fecundity. This present study augments these calculations by combining empirical data on densities of infective L. salmonis copepodids in the field with estimates of the number of gravid L. salmonis on farmed and wild salmonids in Loch Torridon. Data collected between 2002 and 2007 show a significant correlation between mean densities of L. salmonis copepodids recovered in the water column and the numbers of gravid L. salmonis at the local salmon farms. Generally, the farms with greatest numbers of salmon were observed to have stronger correlations with densities of copepodids in the water than the farms with fewer fish. The study suggests that louse management approaches, e.g. treatment trigger levels, need to take account of individual farm biomass, or numbers of fish. This study highlights the importance of control of L. salmonis on salmon farms for the co-existence of both wild salmonid populations and the aquaculture industry. 相似文献
15.
Abstract Isomeric ratios of astaxanthin in eggs and alevins of Atlantic salmon, Salmo salar L., have proven useful in identifying female spawners of farmed origin, but the method underestimates the proportion of fish of farmed origin. The rate of underestimation was studied by analysing astaxanthin content in tissue of 55 farmed Atlantic salmon ascending two Norwegian rivers in the autumn of 1991. The astaxanthin content fell into two distinct classes. Fifty-one per cent of the adult escaped salmon had isomeric ratios similar to salmon fed synthetic astaxanthin, whereas all the remaining fish had ratios similar to wild fish. Discriminant analysis classified 96.4% of the fish with known astaxanthin content into the correct astaxanthin class on basis of tail-fin erosion, length, weight and gill-cover damage. This discriminant function was used to estimate the astaxanthin classification of 1017 farmed salmon caught in nine rivers during 1989–1991. The classification success varied among years from 52 to 64%. Corresponding numbers for females and males were 45–48% and 54–70%, respectively. Thus, estimates of spawning rates of farmed female salmon via astaxanthin content in eggs or alevins from redds should be adjusted accordingly. The observed isomeric ratios of astaxanthin in the escaped farmed salmon and the relationship with morphology indicates that a significant proportion of the escapees ascending rivers have spent more than 1 year in the wild after escape. 相似文献
16.
Incidence and timing of wild and escaped farmed Atlantic salmon (Salmo salar) in Norwegian rivers inferred from video surveillance monitoring 下载免费PDF全文
下载免费PDF全文 Martin‐A. Svenning Anders Lamberg Brian Dempson Rita Strand Øyvind Kanstad Hanssen Per Fauchald 《Ecology of Freshwater Fish》2017,26(3):360-370
Run timing of escaped farmed Atlantic salmon Salmo salar vs. wild fish was compared by the use of video camera surveillance in 15 rivers over several years, covering 1600 km of the Norwegian coastline (from 58°N to 69°N). Annual runs of wild salmon varied among rivers from <200 fish to more than 10 000. During the surveillance period that for most rivers extended from late May to early October, larger‐sized salmon (fish ≥ 65 cm) generally entered the rivers earlier than small fish. The percentage of salmon identified as escaped farmed fish ranged from 0.1% to 17% across rivers with an average of 4.3%. Estimates of escapees are, however, assumed to represent minimum values because an unknown number of farmed fish passing the video cameras may have been misclassified as wild fish. By the use of a linear mixed model and generalised additive mixed models, it was found that the relationship between run timing and fish length differed significantly between farmed and wild salmon. While small‐sized farmed and wild fish (<65 cm) entered the river at about the same time, wild large salmon returned on average 1–2 weeks earlier than similarly sized escapees. The proportion of large‐sized farmed escapees also increased until late August and decreased thereafter. In contrast, there was a relatively constant and lower proportion of small‐sized escapees throughout the season. Within the surveillance period, there was no evidence of any exceptionally late runs of fish classified as escaped farmed salmon. 相似文献
17.
Half a century of genetic interaction between farmed and wild Atlantic salmon: Status of knowledge and unanswered questions 下载免费PDF全文
下载免费PDF全文 Kevin A Glover Monica F Solberg Phil McGinnity Kjetil Hindar Eric Verspoor Mark W Coulson Michael M Hansen Hitoshi Araki Øystein Skaala Terje Svåsand 《Fish and Fisheries》2017,18(5):890-927
18.
Abstract There have been several attempts to distinguish farmed Atlantic salmon by origin using trademarks. Whether there exist different regional markets for salmon, and in particular whether the UK market is separate from the market in continental Europe, is also an issue that has received attention. To address these questions, we investigate the relationship between Norwegian and Scottish salmon both in France and the UK, and between Scottish salmon in France and the UK. The analysis is carried out by investigating how the development of prices is related using co‐integration tests. 相似文献
19.
James Sales 《Journal Of Aquatic Food Product Technology》2013,22(3-4):298-309
Inconclusive results on the effect of farming on fatty acid composition of fish prevent the application of this possible variable in studies related to human health and environmental policies. The current meta-analysis used results from 39 studies to produce compelling quantitative results on differences in fatty acid components related to human health between farmed and wild fish. With seawater fish, mean effect sizes (Hedges' d) for differences in contents of EPA + DHA, total n-3 fatty acids, and the n-3:n-6 ratio were virtually zero. However, farmed freshwater fish showed a lower total n-3 fatty acid content than their wild counterparts. 相似文献
20.
A Review of Factors Influencing Maturation of Atlantic Salmon,Salmo salar,with Focus on Water Recirculation Aquaculture System Environments 下载免费PDF全文
下载免费PDF全文 Sexual maturation of Atlantic salmon, Salmo salar, is a complex process, with many variables having the capacity to influence the timing and prevalence of maturation and acting as promoters and/or inhibitors of sexual development. Precocious maturation has the capacity to seriously impact production in commercial aquaculture settings, and in response there has been a significant amount of research devoted to understanding this issue in order to develop remedial strategies. Very little research has been conducted specifically examining salmon maturation in land‐based, closed containment water recirculation aquaculture systems, which have recently received attention as an alternative technology for the sustainable production of market‐size Atlantic salmon. Unfortunately, the nascent closed containment salmon industry has thus far experienced high levels of precocious maturation, for reasons that are presently unclear. Given the economic challenges facing the closed containment industry's expansion, it is imperative that best management practices be developed to reduce economic losses from early maturation, in order to assist the sustainable growth of farmed Atlantic salmon production. This review provides a brief summary of published research on factors associated with early salmonid maturation, as well as information from research examining maturation and growout performance of Atlantic salmon in closed containment aquaculture systems. 相似文献