2,330 research outputs found
The efficacy of emamectin benzoate against infestations of Lepeophtheirus salmonis on farmed Atlantic salmon (Salmo salar L) in Scotland, 2002-2006
No full textInfestations of the parasitic copepod Lepeophtheirus salmonis, commonly referred to as sea lice, represent a major challenge to commercial salmon aquaculture. Dependence on a limited number of theraputants to control such infestations has led to concerns of reduced sensitivity in some sea lice populations. This study investigates trends in the efficacy of the in-feed treatment emamectin benzoate in Scotland, the active ingredient most widely used across all salmon producing regions. Study data were drawn from over 50 commercial Atlantic salmon farms on the west coast of Scotland between 2002 and 2006. An epi-informatics approach was adopted whereby available farm records, descriptive epidemiological summaries and statistical linear modelling methods were used to identify factors that significantly affect sea lice abundance following treatment with emamectin benzoate (SLICEH, Schering Plough Animal Health). The results show that although sea lice infestations are reduced following the application of emamectin benzoate, not all treatments are effective. Specifically there is evidence of variation across geographical regions and a reduction in efficacy over time. Reduced sensitivity and potential resistance to currently available medicines are constant threats to maintaining control of sea lice populations on Atlantic salmon farms. There is a need for on-going monitoring of emamectin benzoate treatment efficacy together with reasons for any apparent reduction in performance. In addition, strategic rotation of medicines should be encouraged and empirical evidence for the benefit of such strategies more fully evaluated
Buyer and Seller Responses to an Adverse Food Safety Event: The Case of Frozen Salmon in Alberta
No full textFish is a low-fat protein source high in omega-3 fatty acids, but in 2004 consumers also heard that farmed salmon had high levels of polychlorinated biphenyl (PCBs). This research evaluated how Canadian consumers and processors reacted to the conflicting health messages. Demand estimates and time-series analysis of 2001-2006 frozen meat scanner data in Alberta, Canada show a significant drop in salmon expenditure share following the PCB finding. The industry responded by launching low-priced wild salmon products, which contributed to significant demand expansion. The analysis illustrates how a food safety threat was averted and even served as a catalyst for growth.salmon, scanner data, food safety, demand, directed acyclic graphs, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Research Methods/ Statistical Methods, Q10, Q11, Q16, Q22,
Screening of blood and mucus parameters towards breeding for resistance to salmon louse (lepeophtheirus salmonis) in atlantic salmon
No full textOver the last three decades salmon farmers have experienced serious economic hardships due to losses caused by sea lice (Lepeophtheirus salmonis) infestations. In the absence of an effective vaccine, inefficiency of biological control methods and growing concerns over the usage of chemical treatments, there is a quest for alternative strategies to combat this problem. This includes selective breeding approach to increase the innate resistance in fish to the parasite. There is hope that easily measured biomarkers that are correlated to sea lice resistance, exist and can be used to ease recording, reduce cost and increase genetic gain for sea lice resistance. Indications of additive genetic difference in lice resistance in Atlantic salmon (Salmo salar) have led us to hypothesize that biomarkers of resistance are present in the plasma and/or mucus of fish. High throughput Fourier Transform Infrared (FT-IR) profiling of plasma and mucus together with screening of the selected blood parameters (with the help of i-STAT blood gas analyzer) were coupled with multivariate statistical analysis to investigate the differences between two groups (susceptible (S) and Resistant (R)) of Atlantic salmon that shown different in their susceptibility to sea lice. The assignment was based on the sea lice challenge test results of their full-sibs. 65 rainbow trout (Oncorhychus mykiss) were also included in this trial in order to study the species-specific differences for this trait. Fish was challenged twice between late November and early December 2008 and lice were counted for the first time in December 2008 (chalimus sessile stage), followed by second count in January 2009 (pre-adult motile stage) and finally in February 2009 (adult motile stage). A large variation in lice counts both between individual Atlantic salmon and individual rainbow trout was observed. With respect to lice count, S and R groups of Atlantic salmon were different in both sessile and motile stages of lice, indicating genetic background for this trait. Rainbow trout was found to be a more susceptible species than Atlantic salmon in this study, which contradicts most previous studies that suggested Atlantic salmon as slightly more susceptible. Blood parameters are useful measures of physiological disturbance. Most of the measured blood parameters by i-STAT did not show significant differences between the S and R groups of Atlantic salmon, indicating that they were expressed at constitutive levels and not variable due to the low levels of sea lice infection
at the time the sample were recorded. Hematocrit and haemoglobin were found to be very responsive parameters, however, not very specific to the individual lice count. However, the R group of salmon had significantly (P <0.05) higher hematocrit and haemoglobin values than the S group, indicating a genetic background for these parameters. They need to be further examined as the potential inclusion criteria for indirect selection towards increased resistance to sea lice. However, no clustering of S and R groups of Atlantic salmon or Atlantic salmon and rainbow trout with respect to lice count was obtained upon FT-IR spectral analysis of plasma and mucus by Principal Component Analysis (PCA) and Partial Least Squares Regression (PLSR) techniques to differentiate S and R groups of Atlantic salmon or Atlantic salmon and rainbow trout based on number of lice per fish. Moreover, High-throughput FT-IR approach on mucus and blood plasma complemented with classical blood markers at low levels of adult lice present on fish in the final last count did not explain the differences in the number of lice at previous counts. It could be suspected that the variation in FT-IR and i-STAT parameters observed during the last lice count fell within the constitutive (innate) levels of fish. Further studies are still required and metabolomics approach may be more useful at higher level of lice infection to detect the variation in metabolites. However, as the number of lice per grow-out salmon, and thus also breeding candidate, must be kept at very low levels, the metabolomics methods used in this study are not likely to be useful to obtain indirect measures of lice resistance in salmon selective breeding programs
Bibliography of salmonids published in Japan (19): 2004
No full textThis current salmonid bibliography, distributed yearly since 1988, covers scientific publications in Japan. The former eighteen issues were published in Technical Reports of Hokkaido Salmon Hatchery (Fish and Eggs), No. 157-163, Scientific Reports of Hokkaido Salmon Hatchery, No. 49-50, and Bulletin of National Salmon Resources Center, No. 1-7. Titles are given in English for all articles. A reprint of article may be available from the author. An author's address is shown in square brackets following the citation. This 19h issue has covered literature published in 2004. The bibliography is divided into the following sections:articl
Bibliography of Salmonids published in Japan (16): 2001
No full textThis current salmonid bibliography, distributed yearly since 1988, covers scientific publications in Japan. The former thirteen issues were published in Technical Reports of Hokkaido Salmon Hatchery (Fish and Eggs), No. 157-163, Scientific Reports of Hokkaido Salmon Hatchery, No. 49-50, and Bulletin of National Salmon Resources Center, No. 1-4. Titles are given in English for all articles. A reprint of article may be available from the author. An author's address is shown in square brackets following the citation. This 16th issue has covered literature published in 2001. The bibliography is divided into the following sections:articl
Salmon: why bother?
No full textOregonions from diverse backgrounds share their concerns about the Northwest and the role of salmon in the past and its place in our future.an Oregon Sea Grant production.This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Jennifer Gilden, videographer and editor ; executive producer, Joseph Cone.Participants: Jay Nicholas, project leader, Oregon Salmon Plan; Anne Donnelly, executive director, Coos Watershed Association; David Bayles, conservation director, Pacific Rivers Council; Frank Babcok, private landowner, Coos watershed; Elizabeth Woody, author and poet, Confederated Tribes of Warm Springs; Johnny Sundstrum, chair, Siuslaw Soil & Water Conservation District.Electronic reproduction. 2018.Mode of access: Internet from the Oregon Government Publications Collection.In English
Bibliography of Salmonids published in Japan (17)
No full textThis current salmonid bibliography, distributed yearly since 1988, covers scientific publications in Japan. The former sixteen issues were published in Technical Reports of Hokkaido Salmon Hatchery (Fish and Eggs), No. 157-163, Scientific Reports of Hokkaido Salmon Hatchery, No. 49-50, and Bulletin of National Salmon Resources Center, No. 1-5. Titles are given in English for all articles. A reprint of article may be available from the author. An author's address is shown in square brackets following the citation. This 17th issue has covered literature published in 2002. The bibliography is divided into the following sections:articl
Bibliography of Salmonids published in Japan (15): 2000
No full textThis current salmonid bibliography, distributed yearly since 1988, covers scientific publications in Japan. The former thirteen issues were published in Technical Reports of Hokkaido Salmon Hatchery (Fish and Eggs), No. 157-163, Scientific Reports of Hokkaido Salmon Hatchery, No. 49-50, and Bulletin of National Salmon Resources Center, No. 1-3. Titles are given in English for all articles. A reprint of article may be available from the author. An author's address is shown in square brackets following the citation. This 15th issue has covered literature published in 2000. The bibliography is divided into the following sections:articl
- …
