PubMed | Northwest Atlantic Fisheries Center, Animal Health Center and Marine Harvest Canada
Type: Journal Article | Journal: PloS one | Year: 2016
Heart and skeletal muscle inflammation (HSMI) is a significant and often fatal disease of cultured Atlantic salmon in Norway. The consistent presence of Piscine orthoreovirus (PRV) in HSMI diseased fish along with the correlation of viral load and antigen with development of lesions has supported the supposition that PRV is the etiologic agent of this condition; yet the absence of an in vitro culture system to demonstrate disease causation and the widespread prevalence of this virus in the absence of disease continues to obfuscate the etiological role of PRV with regard to HSMI. In this study, we explore the infectivity and disease causing potential of PRV from western North America-a region now considered endemic for PRV but without manifestation of HSMI-in challenge experiments modeled upon previous reports associating PRV with HSMI. We identified that western North American PRV is highly infective by intraperitoneal injection in Atlantic salmon as well as through cohabitation of both Atlantic and Sockeye salmon. High prevalence of viral RNA in peripheral blood of infected fish persisted for as long as 59 weeks post-challenge. Nevertheless, no microscopic lesions, disease, or mortality could be attributed to the presence of PRV, and only a minor transcriptional induction of the antiviral Mx gene occurred in blood and kidney samples during log-linear replication of viral RNA. Comparative analysis of the S1 segment of PRV identified high similarity between this North American sequence and previous sequences associated with HSMI, suggesting that factors such as viral co-infection, alternate PRV strains, host condition, or specific environmental circumstances may be required to cause this disease.
Rogers L.A.,University of Otago |
Peacock S.J.,University of Alberta |
McKenzie P.,Mainstream Canada |
DeDominicis S.,Marine Harvest Canada |
And 6 more authors.
PLoS ONE | Year: 2013
Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis) on domesticated populations of Atlantic salmon (Salmo salar) in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year dataset of monthly sea louse counts on farms in the area to estimate population growth rates in relation to abiotic factors (temperature and salinity), local host density (measured as cohort surface area), and the use of a parasiticide, emamectin benzoate, on farms. We then used the model to evaluate management scenarios in relation to policy guidelines that seek to keep motile louse abundance below an average three per farmed salmon during the March-June juvenile wild Pacific salmon (Oncorhynchus spp.) migration. Abiotic factors mediated the duration of effectiveness of parasiticide treatments, and results suggest treatment of farmed salmon conducted in January or early February minimized average louse abundance per farmed salmon during the juvenile wild salmon migration. Adapting the management of parasites on farmed salmon according to migrations of wild salmon may therefore provide a precautionary approach to conserving wild salmon populations in salmon farming regions. © 2013 Rogers et al.
Rees E.E.,University of Prince Edward Island |
St-Hilaire S.,University of Prince Edward Island |
Jones S.R.M.,Canadian Department of Fisheries and Oceans |
Krkosek M.,University of Toronto |
And 4 more authors.
Landscape Ecology | Year: 2015
Context: Parasite transmission between captive and wild fish is mediated by spatial, abiotic, biotic, and management factors. More effective population management and conservation strategies can result from multivariable assessments of factors associated with spatial dynamics of parasite spillover. Objective: Our study characterised spatial patterns of sea lice (Lepeophtheirus salmonis,Caligus clemensi) infection on out-migrating chum (Oncorhynchus keta) and pink (O. gorbuscha) salmon in an area with Atlantic salmon (Salmo salar) farming. Methods: A multivariable statistical model for sea louse parasitism of out-migrating chum and pink salmon was developed from 166,316 wild salmon sampled in the Broughton Archipelago, British Columbia, Canada from 2003 to 2012. We assessed for factors hypothesized to influence sea lice infection levels, at the non-motile life stage, including spatial scales of infection sources. Results: Fish length, sampling year and method were strong explanatory factors. Infection was greatest in higher salinity water. Farmed and wild juvenile salmon infection levels were correlated, on average, within 30 km. Except for 2004, sea lice infection on farms were typically well below the regulatory level (3 motiles per fish). Average intensity of non-motile infections observed on the wild fish were 6.36 (SD = 9.98) in 2004 compared to 1.66 (SD = 1.25) for the other years. Conclusions: Accuracy of future model estimates will benefit by including hydrodynamic data accounting for anisotropic spread of sea lice from sources. Multivariable statistical modelling over long time series data strengthens understanding of factors impacting wild juvenile salmon infection levels and informs spatial patterns of aquatic epidemiology. © 2015, Springer Science+Business Media Dordrecht.
Kilburn R.,Marine Scotland - Marine Laboratory |
Murray A.G.,Marine Scotland - Marine Laboratory |
Hall M.,Marine Scotland - Marine Laboratory |
Bruno D.W.,Marine Scotland - Marine Laboratory |
And 2 more authors.
Aquaculture | Year: 2012
Epidemiological studies of pancreas disease (PD) in Scottish farmed Atlantic salmon (Salmo salar L.) were conducted by analysing a marine Atlantic salmon farming company's production data on over 60. million fish between 1998 and 2009. Presumptive PD diagnoses were made by farm managers with advice from fish health professionals. Mortality ascribed to PD was negligible before 2003 but rose to a peak in 2006 and 2007, accounting for 94% and 86% of disease losses in 2006 and 2007 respectively, followed by a decline in 2008 and 2009. PD mortalities primarily were reported in larger fish (2-5. kg) and accounted for the largest loss in biomass due to any infectious disease including infectious pancreatic necrosis (IPN). The mean monthly numbers of fish lost to PD were higher in July through September. The distribution of mortality between PD infected production cycles was highly skewed with one production cycle accounting for 26% of the total reported mortality. The results showed no evidence that PD in a production cycle was related to a subsequent PD outbreak (with an odds ratio of 0.93 relative to farms that had not experienced PD however this OR has large confidence intervals). The analysis of the industry production data has provided information on the prevalence, intensity and spread of PD in Scotland at a level of detail and, crucially, over a relatively long period that would be impossible to obtain from official statistics on this non-notifiable disease. © 2012.
Saksida S.M.,British Columbia Center for Aquatic Health science |
Greba L.,Kitasoo Fisheries Program |
Morrison D.,Marine Harvest Canada |
Revie C.W.,University of Prince Edward Island
Aquaculture | Year: 2011
The Kitasoo/Xai'xais First Nation established a program to monitor sea lice levels on seaward migrating wild juvenile salmon in their traditional territory which contains the most northerly salmon farming region of British Columbia. A total of 12 locations were routinely sampled during the period between 2005 and 2008 to gain a better understanding of the levels and patterns of sea lice infestation on wild salmonids in the region. Over 5000 juvenile salmon were collected and examined for sea lice. Around 78% were identified as pink salmon, 18% were chum salmon and the remainder classified as 'other' salmon (coho and sockeye salmon). Two species of sea lice were observed: Lepeophtheirus salmonis and Caligus clemensi. Over 91% of all the juvenile salmon examined had no sea lice and there was no significant difference in L. salmonis prevalence levels among salmon species. However, chum salmon had significantly lower C. clemensi prevalence levels than either pink or 'other' salmon. There were significant annual and regional differences in L. salmonis prevalence on juvenile pink salmon; the lowest prevalence in all sampling zones occurring in 2008, while channels containing salmon farms consistently had higher levels than those without salmon farms. Mean prevalence of L. salmonis in the channels with salmon farms ranged from 2% to 9% which is lower than levels published for the same region in different years or for other areas without salmon farms. C. clemensi prevalence on wild pink salmon was associated with sampling zone and the size of pink salmon; larger juvenile fish were more likely to be infected than smaller fish. During the period of wild juvenile salmon migration, the mean abundance of motile stages of L. salmonis on farmed salmon ranged from 0.13 to 0.79 lice per fish but there were no significant differences among years. In comparison, C. clemensi abundance levels on farms were significantly higher in 2005. Factors contributing to variations in these observations are discussed. © 2011.
PubMed | Marine Harvest Canada
Type: Journal Article | Journal: The Canadian veterinary journal = La revue veterinaire canadienne | Year: 2013
Marine Havest Canada has significantly reduced its antimicrobial usage in salmon farming over the last 8 years. Change has come about largely through improvements in production, health management, and livestock selection. However, antimicrobial treatments are still required for stomatitis and bacterial kidney disease. Lack of efficacious vaccines and the limited number of licensed antimicrobials available to the industry continue to be of concern.
PubMed | Marine Harvest Canada, U.S. Geological Survey, AFBI Stormont, Pacific Biological Station and British Columbia Center for Aquatic Health science
Type: Journal Article | Journal: PloS one | Year: 2015
Piscine reovirus (PRV) is a double stranded non-enveloped RNA virus detected in farmed and wild salmonids. This study examined the phylogenetic relationships among different PRV sequence types present in samples from salmonids in Western Canada and the US, including Alaska (US), British Columbia (Canada) and Washington State (US). Tissues testing positive for PRV were partially sequenced for segment S1, producing 71 sequences that grouped into 10 unique sequence types. Sequence analysis revealed no identifiable geographical or temporal variation among the sequence types. Identical sequence types were found in fish sampled in 2001, 2005 and 2014. In addition, PRV positive samples from fish derived from Alaska, British Columbia and Washington State share identical sequence types. Comparative analysis of the phylogenetic tree indicated that Canada/US Pacific Northwest sequences formed a subgroup with some Norwegian sequence types (group II), distinct from other Norwegian and Chilean sequences (groups I, III and IV). Representative PRV positive samples from farmed and wild fish in British Columbia and Washington State were subjected to genome sequencing using next generation sequencing methods. Individual analysis of each of the 10 partial segments indicated that the Canadian and US PRV sequence types clustered separately from available whole genome sequences of some Norwegian and Chilean sequences for all segments except the segment S4. In summary, PRV was genetically homogenous over a large geographic distance (Alaska to Washington State), and the sequence types were relatively stable over a 13 year period.
PubMed | Marine Harvest Canada, British Columbia Ministry of forests, Institute Acuicultura Of Torre Of La Sal Iats Csic, Deakin University and Center for Aquatic Health science
Type: Journal Article | Journal: Journal of fish diseases | Year: 2016
Kudoa thyrsites (Myxozoa) encysts within myocytes of a variety of fishes. While infected fish appear unharmed, parasite-derived enzymes degrade the flesh post-mortem. In regions of British Columbia (BC), Canada, up to 4-7% of fillets can be affected, thus having economic consequences and impacting the competitiveness of BCs farms. K.thyrsites was monitored in two farms having high (HP) or low (LP) historical infection prevalence. At each farm, 30 fish were sampled monthly for blood and muscle during the first year followed by nine samplings during year two. Prevalence and intensity were measured by PCR and histology of muscle samples. In parallel, fillet tests were used to quantify myoliquefaction. Infections were detected by PCR after 355 and 509 degree days at LP and HP farms, respectively. Prevalence reached 100% at the HP farm by 2265degree days and declined during the second year, whereas it plateaued near 50% at the LP farm. Infection intensities decreased after 1year at both farms. Blood was PCR-positive at both farms between 778 and 1113degree days and again after 2000degree days. This is the first monitoring project in a production environment and compares data between farms with different prevalence.
News Article | February 15, 2017
Med bakgrunn i operasjonelt driftsresultat, samt utsikter til et sterkt marked fremover og en solid finansiell posisjon, har styret besluttet et kvartalsutbytte på NOK 2,80 per aksje. Marine Harvest Norway oppnådde et operasjonelt driftsresultat per kg på EUR 2,70 (1,47) i fjerde kvartal, mens Marine Harvest Scotland og Marine Harvest Canada oppnådde et operasjonelt driftsresultat per kg på henholdsvis EUR 1,83 og EUR 3,33 (EUR -0,30 og EUR 0,36). Marine Harvest Chile oppnådde et operasjonelt driftsresultat per kg på EUR 2,61 i kvartalet (EUR -1,31). Consumer Products rapporterte et operasjonelt driftsresultat på EUR 22,9 millioner (EUR 9,8 millioner). Marine Harvest Fish Feed fikk et operasjonelt driftsresultat på EUR 10,8 millioner (EUR 8,0 millioner).