Genetic mixing with farmed salmon can change the genetic composition of wild populations, lead to changes in life history parameters and even cause population decline. In Iceland, aquaculture of salmon of Norwegian origin is a growing industry. The production of farmed salmon has gone from almost nothing in 2010 to 43,000 tons in 2022. According to the current advice of the Norwegian Marine Research Institute (risk assessment of genetic mixing), it is estimated that it is possible to raise 106,500 tons of fertile salmon without causing a negative impact on useful wild populations. salmon
In a genetic study from 2017, where 15 microsatellites were used, signs of genetic admixture were found in rivers close to seagull farming in the Westfjords. In this study, salmon samples were taken in rivers around the country and the number of samples was almost ten times higher. A total of 6,348 salmon fry from 89 rivers were studied and emphasis was placed on areas in the vicinity of sea pig farming.
Most samples belonged to the spawning cohorts of 2014-2018, when the production of farmed salmon was around 6,900 tons on average. Samples were genetically analyzed with 60,250 alleles (SNP genetic boundaries) and the genetic information of 250 farmed salmon was used for comparison. The coefficient of genetic difference (FST) between Icelandic salmon and farmed salmon was 0.14 on average (based on 34,700 SNPs) and 0.62 for the genetic boundaries that showed the greatest separation between the two groups (196 SNPs). Genetic admixture was analyzed by multivariate analysis (PCA) and in the models of the programs ADMIXTURE, STRUCTURE and NewHybrids.
A total of 133 first-generation hybrids (offspring of farmed and wild salmon) were detected in 17 rivers (2.1% samples, within 18% rivers). Older admixture (second generation or older) was detected in 141 juveniles in 26 rivers (2.2% samples, within 29% rivers). First-generation hybrids were more common in the Westfjords than in the Eastfjords, which is consistent with the fact that the fire in the Eastfjords started later and has been less extensive.
Hybridization was usually detected less than 50 km away from breeding areas, but some hybrids were found up to 250 km away. On the other hand, older genetic admixture was more frequent in the Eastfjords than in the Westfjords and is most likely related to the fire that operated there at the beginning of this century. Older genetic admixture was most evident in Brei\u00f0dals\u00e1 and was detected in 32% (72 out of 228) of the juveniles. More research is needed on the intergenerational distribution of hybrids, the extent and causes of the spread of older admixtures.
As mentioned above, the study analyzed the effects from the early years of the current farming, when production volumes were low, and older experiments in sea pig farming. The results in this report show that genetic mixing has occurred at relatively low breeding rates.<\/p>","protected":false},"excerpt":{"rendered":"
Erf\u00f0abl\u00f6ndun vi\u00f0 eldislax getur breytt erf\u00f0asamsetningu villtra stofna, leitt af s\u00e9r breytingum \u00ed l\u00edfs\u00f6gulegum \u00fe\u00e1ttum og jafnvel valdi\u00f0 hnignun stofna. […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"template-greinar.php","format":"standard","meta":{"_acf_changed":false,"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[2011],"tags":[],"class_list":["post-51389","post","type-post","status-publish","format-standard","hentry","category-greinar"],"acf":[],"yoast_head":"\n