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2015
VKM has assessed the positive and negative effects on biodiversity were sterile salmon to be used in Norwegian aquaculture. Triploidisation is assessed as the most effective method for sterilising fish, but it can affect the welfare and health of the fish.
Several other techniques for producing sterile salmon are being tested, but it is too early to determine whether they can be used in large-scale farming.
This is the key message in a knowledge summary VKM has prepared for the Norwegian Environment Agency.
Background
Escaped farmed salmon poses a major threat to wild salmon in Norway. hey can interbreed with wild salmon, genetically alter them, and make the populations less adaptable and more vulnerable to disease and environmental changes. A possible solution to the problem may be to use sterile salmon in farming.
To date, only triploidisation has been tested. Newly fertilised eggs are given a hydrostatic pressure shock, thereby retaining an extra set of chromosomes which render the fish sterile. This method is currently the only one tested on a large scale. Triploidisation is effective but can also pose health and welfare challenges to fish.
Methods
VKM has reviewed available scientific literature regarding methods that can be used to produce sterile salmon. VKM has assessed whether these methods work as well, or better, than triploidy and whether they are likely to have fewer negative effects on fish welfare. Assessments have also been made of whether farmed fish treated with other sterilisation methods pose a greater or lesser threat to wild salmon than traditional farmed salmon.
VKM has looked at the possibilities for further development of the triploidisation technique and has also assessed various methods currently being tested for producing sterile fish. Some of these are still at the laboratory-testing stage, while others are approaching trials with release into sea-pens. VKM has grouped the different methods based on whether they cause permanent changes in the genome (so-called "knock-out" of important genes) or whether the changes only result in temporary blocking or downregulation of gene expression (so-called "knock-down").
Results
VKM concludes that triploidisation remains the most effective method and that there are possibilities to further develop this methodology through targeted breeding and adjustments in how the fish are kept. These measures can potentially solve the challenges for fish health and welfare. Using pure triploid female lines can also reduce some of the other challenges by preventing spawning interactions in rivers and reducing disease transmission to wild salmon.
Alternative sterilisation methods, such as gene editing, vaccination, and temporary downregulation of proteins for gonad development using antisense oligomers and egg immersion, are promising but still under development.
VKM assesses that methods causing permanent changes in the genome of diploid fish have a higher inherent risk than methods that only affect gene expression.
Hope in egg-bathing
Perhaps the most promising technique for safe production of sterile salmon is to add synthetic oligonucleotides to the eggs at an early stage, thereby preventing germ cell development without causing any inheritable changes. Such oligonucleotides can be injected into the eggs or absorbed by the eggs through bathing (immersion) in a special solution.
"Especially the method involving targeted 'tools,' such as oligonucleotides that prevent germ cell development and can be added to the eggs in a water bath, seems promising," says Johanna Bodin, member of the Panel for Genetically Modified organisms and spokesperson for the report.
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2025
2015
2013
Norsk institutt for vannforskning
2018
2014
2024
2000
2000
2020
Oslo Citizens' Observatory. Results from the Oslo Empowerment Initiative as part of the CITI-SENSE project. NILU report
CITI-SENSE prosjektet har blitt initiert for å etablere såkalte Citizens' Observatorier i forskjellige byer i Europa. Ved å bruke forskjellige lavpris måleinstrumenter skulle folk flest bli i stand til å påvirke beslutningene som berører luftkvaliteten i deres nærområder. Som del av CITI-SENSE gjennomførte vi undersøkelser i ni europeiske byer. Denne rapporten inneholder resultatene fra aktivitetene gjennomført i Oslo Citizens' Observatoriet, aktiv i tidsrommet mellom desember 2015 og september 2016. Vi presenterer verktøy og tjenester vi brukte, innsamlede data og målinger samt brukernes vurdering av verktøyene og aktivitetene i Oslo. Vi avslutter med å presentere våre erfaringer fra aktiviteter som hadde som mål å engasjere befolkningen i miljøovervåkning.
2017
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Ormen Lange landanlegg. Konsekvenser av utslipp til luft - oppdatering av tidligere rapport. NILU OR
2008