Salmon, Atlantic (Caught at sea)

Salmo salar

Method of production — Caught at sea
Capture method — Drift and fixed net
Capture area — North East Atlantic (FAO 27)
Stock area — NE Atlantic
Stock detail

All Areas


Picture of Salmon, Atlantic (Caught at sea)

Sustainability rating five info

Sustainability overview

Wild Atlantic salmon are depleted over much of their range including around the UK - see separate Good Fish Guide entries for England and Wales and Scotland. There may be several reasons for this. Factors include: marine mortality, linked to ocean climate and productivity; pollution; environmental changes; aquaculture; freshwater habitat deterioration; and impediments to migration routes. Atlantic salmon is also listed by OSPAR as a threatened and declining species. ICES scientists recommend that fishing for salmon only takes place in rivers where stocks are at full reproductive capacity or above conservation limits. Avoid eating wild-caught salmon from rivers below these limits. For details of rivers above these limits in England and Wales see the Environment Agency and Natural Resources Wales websites. For information on the sustainability of the salmon stocks in rivers in Scotland see the Marine Scotland website. Avoid eating wild-caught salmon from rivers where the stock is known to be depleted or from any mixed stock fishery.

Biology

The Atlantic salmon is one of 4 species of salmonids indigenous to European waters. Salmon move between fresh and seawater during their lifecycle. This is referred to as being “anadromous”. They spend most of their lives in fresh water and are termed benthopelagic. Atlantic salmon matures at a length of around 73 cms. Maximum length for males is 150 cms, 120 cms for females. Maximum reported age is 13 years, but most individuals only reach 4-6 years. Adult fish return to their birth or natal river from January until November and spawn in late Autumn/early Winter. The eggs, which are laid in nests termed “redds”, hatch in April to May and are called alevins. Young fish, which are known firstly as fry and later as parr as they mature, remain in fresh water for 1 to 6 years, then migrate to coastal marine waters, or even the open oceans, between April and May. They have undergone a physiological change to enable them to live at sea and are now termed smolts. Adult salmon return to spawn after spending up to 4 years at sea. Many die after spawning but a number survive to spawn a second or third time. The mechanism by which salmon navigate with such precision back to their birth or natal river to spawn is not fully understood. In the ocean, the earth’s magnetic field and the stars may be important. When the salmon reach coastal waters, smell and taste allow precise homing to their river of birth. One of the key biological differences between Atlantic salmon (Salmo) and Pacific salmon (Onchorynchus) is that Atlantic salmon are iteroparous, that is, they do not die after returning to spawn in the rivers in which they hatch. Pacific salmon, and other members of the Onchorynchus genus on the other hand, are referred to as being semelparous, with mature members of the population generally dying within a few days or weeks of spawning.

Stock information

Stock Area

NE Atlantic

Stock information

Salmon stocks across the North Atlantic remain at historically low levels. This is despite fairly restrictive management measures and reductions in fisheries and exploitation rates. ICES recommends that fishing for salmon only takes place in rivers where stocks have been shown to be at full reproductive capacity i.e. above conservation limits (CLs). Atlantic salmon is also listed by OSPAR as a threatened and declining species. Marine mortality, linked to changing ocean climate and productivity, is much higher than in the past and appears to be a major driver of abundance in the North Atlantic. The decline in salmon stocks is also attributed to overfishing, freshwater habitat deterioration and impediments (e.g. dams) to upstream movements. Fishing pressure on wild stocks has decreased due to intensive farming of salmon - the world-wide production of farmed Atlantic salmon in 2012 was over 1300 times the reported nominal catch of Atlantic salmon in the North Atlantic - but other problems have increased. Farmed salmon escape in large numbers and may move into any river and hybridize with wild salmon stocks and trout (Salmo trutta). Diseases such as furunculosis, corynebacterial kidney, enteric red mouth, fin rot and fungus infections are also problematic.

Management

Due to the Atlantic salmon’s oceanic migrations, international cooperation is essential to its conservation, restoration and rational management. The forum for such cooperation is provided by the North Atlantic Salmon Conservation Organization (NASCO). Under NASCO’s Convention, fishing for salmon is prohibited beyond 12 nautical miles of the baselines in most parts of the North Atlantic Ocean, thereby creating an enormous protected zone free of directed salmon fisheries. NASCO has established regulatory measures or decisions for the distant-water fisheries at West Greenland and around the Faroe Islands in most years since its establishment. The International Council for the Exploration of the Sea (ICES) has provided scientific advice to NASCO since its establishment in 1984. This advice indicates that there has been a marked decline in abundance prior to any fisheries, and while marine survival indices in the North Atlantic have improved in some index stocks in recent years, the declining trend has persisted and survival indices remain low. Factors other than marine fisheries, acting in freshwater and in the ocean (e.g. marine mortality, fish passage, water quality) are contributing to continued low abundance of wild Atlantic salmon. In response to the declining abundance, there have been major reductions in fishing effort around the North Atlantic; the combined harvest in the distant-water fisheries has averaged 22 tonnes over the last ten years. In 2001, NASCO established the International Atlantic Salmon Research Board (IASRB) to promote collaboration and co-operation on research into the causes of marine mortality of Atlantic salmon and the opportunities to counteract it. The Board developed and implemented, through a public-private partnership, an innovative and comprehensive programme of marine research, the SALSEA Programme, investigating the distribution and migration of salmon at sea and is currently reviewing the need for further research to partition marine mortality at different stages along the migration route (see www.nasco.int/sas ).

Capture Information

High seas and coastal drift netting takes large numbers of fish as they return to rivers to spawn. The use of fixed gill nets at sea is generally prohibited by law in UK waters.

References

http://www.nasco.int/pdf/2013%20papers/CNL_13_8.pdf