Trout, Rainbow

Oncorhynchus mykiss

Method of production — Farmed
Production country — UK
Production method — Open net pen and cage
Picture of Trout, Rainbow

Sustainability rating three info

Sustainability overview

Trout farming was introduced into the UK in the 1950’s, and now there are over 300 trout farms. Rainbow trout is the most popular farmed species of trout, with most of production occurring in a variety of enclosures in freshwater. In Scotland trout can be farmed in cages in freshwater lochs. It takes approximately 7-8 months for trout to reach harvesting size. Trout are carnivorous fish whose feed relies on wild fisheries. Buying organic farmed trout is the best choice to make as fish stocking densities are generally lower in comparison to non-organic farms, feed is sourced sustainably and welfare of a high standard.

Feed Resources

Criterion Score: -1 

Trout feed is traceable to ingredient level however the sustainability of the ingredients cannot be assured. Trout have a significant requirement for fish in their diet, much higher that Atlantic salmon.


Environmental Impacts

Criterion Score: -1

Rainbow trout farming is managed by the countries agencies who control water and chemical use and discharges. Escapes are small scale and have little effect on surrounding wild trout as the farmed fish are infertile. Lethal control of predators is permitted.


Fish Health and Welfare

Criterion Score: 1

Welfare and humane slaughter criteria are included as part of the production standards.



Criterion Score: 3

There is no regional level planning but there is a range of regulations to address most of the issues of environmental concern and these are deemed to be broadly effective although specific data is lacking. The species is farmed to British Quality Trout standards.


Production method

Open net pen and cage

Farming trout in open net pens in freshwater lakes and loch systems allows discharges of organic waste and nutrients directly into the environment. Production is such systems can also lead to escapes.


Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below. Click on a name to show the sustainable options available.

Anchovy, anchovies
Arctic char
Herring or sild
Salmon, Atlantic (Farmed)
Salmon, Chinook, King Salmon
Salmon, Chum, Keta, Calico or Dog salmon
Salmon, Coho , Silver, White
Salmon, Pink, Spring , humpback
Salmon, Sockeye , Red Salmon, Bluebacks, Redfish
Sprat, whitebait
Trout, Rainbow
Tuna, albacore
Tuna, bigeye
Tuna, skipjack
Tuna, yellowfin


A member of the salmonid family, rainbow trout are native to western North America and range from Alaska to Mexico. They can grow up to 120cm in length and live to an average age of 11 years. They prefer freshwater and require fast flowing water to breed


British Trout Association, Personal Communication. 17/10/2012

FAO 2005-2018. Cultured Aquatic Species Information Programme. Oncorhynchus mykiss. Cultured Aquatic Species Information Programme . Text by Cowx, I. G. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 15 June 2005. [Cited 12 September 2018].

Quality Trout UK standards. Available online at:

CEFAS.Details for Epizootic Haematopoietic Necrosis. Available online at:


Scottish Government:

Scottish Government:

Aquaculture and Freshwater Fisheries Act (2012) , WEWS Act 2003. EIA (Scotland) Regulation 1999, Alien and Locally Absent Species in Aquaculture (2007) Europe."Health requirements & disease control:Aquatic Animal Health (Scotland) Regulations 2009, which implement Directive 2006/88/EC. Available online at: