Acronym NA
Category
Fisheries
Title Betydning av lakselus fra oppdrettslaks for populasjoner av villaks: Forprosjekt - Significance of salmon lice from farmed salmon for wild salmon populations: Preliminary project Programme National Programme
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National Coordinator Arnfinn Aunsmo Coordinator email arnfinn.aunsmo@nvh.no
Coordinator institution
NVH - Norwegian School of Veterinary Science (Norway)
Institutions involved
NINA - Norwegian Institute for Nature Research (Norway) ,
NIVA - Norwegian Institute for Water Research (Norway) ,
NVI - Norwegian Veterinary Institute (Norway) ,
NA - SINTEF Ocean (Norway) ,
NA - Uni Research AS (Norway) ,
Start year 2013 End year 2013 Funding (€) € 24,543 Website https://www.fhf.no/prosjekter/prosjektbasen/900898/ Summary A working meeting was conducted with participation from the industry and from the research institutions NINA - Norwegian Institute for Natural Research, Uni Research, SINTEF, the Norwegian Institute for Water Research - NIVA, the Norwegian Veterinary College and the Veterinary Institute. The Institute of Marine Research was also invited but did not have the opportunity. Posts were presented on various projects and methods that may be relevant for developing more knowledge about how salmon lice affect wild salmon populations, and various possible approaches were discussed. The main report aims to evaluate (scientific) methods that are used or can be used to quantify the effects of salmon lice on wild salmon stocks. This is an area that is described as one of the aquaculture industry's biggest challenges with regard to sustainability and which is pointed out as a threat to the wild axis. Many factors have been described that can affect the survival and return of wild salmon, with variation between years and as a general development over time. Many of these factors covariate and influence each other. Thus, a statistical analysis (of possible risk factors) must be based on an imaginary diagram of relationships between different factors and take into account and include as many of such factors as possible. Quantification of both the wild salmon population and possible threat factors is demanding, and lack of accuracy in quantification will increase the risk of erroneous findings. Monitoring of lice on wild salmonids is extensive. Harmful limits for lice on salmonids have been established, but there is some variation in the description of harmful levels. In risk assessments of the effects of lice on wild fish, the proportion of fish above these limits is used in the assessment of the threat picture. There is a lot of data from monitoring on sea trout and less on wild salmon. Such monitoring provides a direct answer to the amount of lice on wild fish and with good knowledge of harmful limits and representative monitoring, this will provide good insight into the amount of lice on wild fish. The wild ax is a migratory species and is inaccessible for monitoring and registration. Data and knowledge about wild salmon are therefore demanding to obtain. The results from the monitoring of sea trout should be investigated for whether they can be transferred to wild salmon and thus be able to provide an increased understanding of the effects of lice on wild salmon. Studies have been done that show an increased incidence of lice on wild fish in areas with intensive farming. It should be possible to design studies that can reveal factors of importance for the connection between lice in farming and lice in wild fish. However, studies based on several years of monitoring of wild salmonids (mainly sea trout) show significant methodological challenges where a sufficient number of observations is pointed out as a major challenge. It will be particularly demanding to obtain enough observations from wild salmon for such studies and analyzes. The incidence and level of lice are monitored weekly in all Norwegian fish farms, and such data can be used to calculate an infection pressure against wild fish. Well-validated models for lice reproduction combined with the level of lice in the facilities can be used for continuous monitoring of infection pressure against wild fish. Sources of infection can thus be identified and interventions can be targeted. The effects of various threat factors on wild salmon stocks can be calculated in mathematical simulation models, where models can also be created that simulate the effects of salmon lice. Such models are necessarily complicated by many sub-models, each of which contains variation and uncertainty. Accumulation of variation and uncertainty in such complex models can leave very wide interpretations. Systematic errors in the model itself or in the data basis can lead to incorrect calculation of the effects. It has been shown that lice larvae can be traced back to their origin by using isotope analyzes and thus determine whether they originate from mother lice on wild fish or farmed fish. Especially in situations where the infection does not follow the known spread pattern, this method is important for understanding the infection dynamics. The method can thus complement both monitoring and statistical analyzes. Release trials with antiparasitic-treated smolt groups and registration of return migration can be used to calculate the degree of return migration between treated and untreated groups, and indirect population effects. However, there is great variation between publications in methodology used in interpreting the effects. In such studies, a standardized methodology should be established for the assessment of the population effects. The treatments are done with broad-spectrum antiparasitic agents where reduced negative effect of parasites other than salmon lice can be part of the overall effect. The effect of treatment on other parasites should be quantified.
Keywords
Salmon;
Wild animals;
Fish;
Open sea aquaculture;
Cage aquaculture;
Environmental impact;
Parasite;
Fish health;
Marine Region
76
Not associated to marine areas
0
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