Salmon

28 Jul

Atlantic Salmon - Scientific name - Salmo salar

Conservation status

Salmon is the most popular fish consumed in the UK.

Atlantic Salmon is listed on the IUCN Red List as Near Threatened. They report that there are ‘a multitude of threats to the species which have led to reported declines in the global population size over the last three generations,’ (IUCN). Salmon are also on the Greenpeace Red List.

MCS advise consumers to ‘think before they buy’. They particularly advise against buying Wild Atlantic Salmon as stocks are ‘dangerously’ low. They say most Salmon sold in the UK are fish farmed.

Fish farming has its own issues. There are concerns around the large number of wild fish used to feed farmed salmon as well as the conditions some farms keep them in.

The Wildfish Organisation campaigns against open-net salmon farming: ‘poorly run and badly sited open-net salmon farms put wild salmon at risk from parasites and diseases. Farmed fish that escape these open-net pens threaten the genetic integrity of wild salmon and further compromise their future survival.’

Overview

Atlantic Salmon are anadromous fish, meaning they live in both fresh and saltwater. Salmon hatch in the shallow gravel beds of freshwater headstreams and spend their juvenile years in rivers, lakes and freshwater wetlands. They migrate to the ocean as adults and live like sea fish often travelling far into the ocean, before returning to their freshwater birthplace to reproduce. Salmon have a unique ‘homing’ instinct that allows them to return home as far as 2,000 miles.

In the natural environment the fish spawns in freshwater and alevins (~ 2 cm) emerge from eggs, subsisting off the attached yolk sac until reaching the fry stage when they are ready to accept exogenous food. The young remain in freshwater for 2 to 5 years depending on the water temperature and food supply. Prior to migration, smolts undergo physiological and behavioural changes, a process called smoltification that prepares them for their life at sea. After spending 1–2 years at sea, they return to their freshwater rivers to spawn. At sea, the Atlantic Salmon prefers temperatures from 4 to 12 ˚C. Salmon farming requires both freshwater and saltwater operations. Because of the efficiencies of farm husbandry practices, the farming process accelerates the life cycle to 1 year or less in freshwater and from 10 to 15 months at sea. (Source FAO)

Atlantic Salmon are much larger than trout; they are silvery with a few dark spots on the back and may have a pinkish flush to the belly. They typically grow to around 120cm but can be as large as 150cm. They live for a maximum of 13 years.

The Salmon diet changes during their life. Beginning with plankton early in their life, they eat aquatic insects, small crustaceans, tadpoles and small fish as Juveniles before moving on to mid-sized fish such as herrings, mackerels, lanternfish and squid as adults.

They are preyed upon by larger fish like tuna and sharks, as well as marine mammals like seals and orcas. In freshwater, birds such as herons, and mammals like otters.

A deeper look into Fish Farming

Farmed Salmon, from Norway and Scotland, is by far the most popular fish in the UK, with 35% of the total seafood retail sales value, selling over 76,000 tonnes in a year (Nielsen Scantrack YE 14/06/25). Farmed Atlantic salmon global production in 2025 could reach 2.93 million tonnes with Norway expected to reach 1.56 million tonnes. (FAO).

The global salmon farming industry is projected to grow 40% by 2033, according to a report from seafood market analysis firm Kontali. This is driven by advances in fish health, land-based farming, and new technologies.

Wild Alaskan (Pacific) Salmon catches are expected to remain stable at 800,000 to 900,000 tonnes per year.

The discussions around fish farming are complicated but include concerns around the use of wild caught fish used to feed Salmon. However this has reduced substantially from, 2–4 kg of wild-caught fish to 0.67kg needed to produce one kilogram of Salmon, between 2000 and 2020 (Naylor, Rosamond and IFFO). This has been achieved through advances in finding alternative feed ingredients including using vegetable based proteins like soy (100% sourced from certified deforestation free sources). Other concerns are the risk of escapes from farms and the presence of sea lice in farms that can spread to wild fish and harm the salmon if they are not monitored and removed. Farming environmental conditions and fish health are addressed in the farming standards developed by the Aquaculture Stewardship Council and GlobalGAP, both of which are checked via independent audits.

Sources

FAO - https://www.fao.org/fishery/affris/species-profiles/atlantic-salmon/atlantic-salmon-home/en/ and https://openknowledge.fao.org/server/api/core/bitstreams/b0e8467b-3a2d-4b88-89e3-9dbf3569485e/content

https://www.pittmanseafoods.com/

Naylor, Rosamond L. "Nature's Subsidies to Shrimp and Salmon Farming" (PDF). Science; 10/30/98, Vol. 282 Issue 5390, p883. Archived from the original (PDF) on 26 March 2009.

IFFO - https://www.iffo.com/ffdr-data (origin data from FAO)

Wikipaedia https://en.wikipedia.org/wiki/Salmon

Marine Conservation Society - https://www.mcsuk.org/goodfishguide/species/atlantic-salmon/?search=salmon

IUCN – https://www.iucnredlist.org/species/196579912/196580931

Greenpeace - http://www.greenpeace-fishforlife.50webs.com/redlists.html

Wildfish - https://wildfish.org/project/atlantic-salmon-campaign/

Nielsen Scantrack data from Seafish report Seafood consumption 2025

https://www.seafish.org/document/?id=36326

Joseph Cox