The stock size of Atlantic salmon has decreased significantly in many places within the species' distribution area. There are many indications that the causes can be traced to increased declines in salmon stocks.
In 2008, a multinational research project, Salsea Merge, was launched, with the main goal of finding an answer to the question of why salmon catches at sea have increased. A database on the genetic composition of salmon in hundreds of salmon stocks was developed. Through genetic analysis and comparison with the database, it is now possible to trace salmon that are caught in the sea to their homelands, but such knowledge is the key to examining how the grazing areas in the Atlantic are handled by salmon stocks.
Little has been known about salmon routes in Icelandic waters. Salmon fishing has been banned since 1932 and salmon is not allowed to be landed, despite the fact that salmon are known to be used as by-catch in various fishing gear. Attempts were made to obtain samples from fishing vessels from 2007 and in exploratory fishing, and 32 samples were collected. In 2010, a new research campaign was launched in collaboration with the Directorate of Fisheries in connection with fishing for mackerel in Icelandic waters, and the campaign has now yielded an additional 175 samples.
The aim of the project was to investigate the age composition, growth and origin of salmon caught in the waters off Iceland. Samples have been analyzed from 2007 to 2010, but their 86% was collected from the mackerel fishery in 2010. Most salmon were found in their second year at sea (78%), but the proportion of salmon that had stayed two years or longer turned out to be 17.5%. Several juvenile salmon were also caught in the first year at sea (4.4%). The freshwater age ranged from 1 to 6 years, and salmon with a two-year freshwater stay were the most common (46.2%), while a three-year freshwater stay was also common (25.3%). The average age of freshwater salmon was 2.4 years.
Most of the salmon were caught within the Icelandic fishing jurisdiction. Most of the samples were caught in the east of the country, but there were also samples of salmon caught in the south and west of the country. Most juvenile salmon were caught west of Snæfellsnes. The origin of salmon was analyzed in 150 samples. Of this number, only 8 samples (5%) were of Icelandic origin. The results indicate that important routes and grazing areas for salmon can be found within the Icelandic fishing jurisdiction.
There are many indications that salmon, especially from the southern part of the distribution area from France to the southern part of Norway with the British Isles, use the sea areas around Iceland as grazing areas during part of their life cycle and could be on their way to known salmon grazing areas in East and West Greenland. of Iceland. Salmon of Icelandic origin proved to be an insignificant part of the samples and it was also a short age - and growth data. Salmon in the samples thus showed much faster growth at the juvenile stage than is the case with Icelandic salmon stocks, as Icelandic salmon stay for the most part 3 -5 years in freshwater before going to sea.
The parties in this project are: Veiðimálastofnun, www.veidimal.is, Directorate of Fisheries, www.fiskistofa.is and Matís.
Project sponsor: The Fisheries Project Fund.
For further information, please contact Kristinn Ólafsson at Matís, kristinn.olafsson@matis.is.