Prawn, King (whiteleg), prawns

Litopenaeus vannamei

Method of production — Farmed
Production country — UK
Production method — Closed land based system
Picture of Prawn, King (whiteleg), prawns

Sustainability rating one info

Sustainability overview

Updated: November 2019.

Land based warmwater prawn farming is a new development, particularly in the UK. Producing prawns in this way addresses many of the issues of environmental concern associated with conventional open water intensive prawn production as this is a fully closed system. This includes issues such as habitat damage; pollution of groundwater; escapes and disease transfer. Feed sustainability is a concern as it cannot be verified that prawns in this system are using a certified feed source.

Feed Resources

Criterion score: -2 info

King prawns are fed a commercial pelleted diet that includes fishmeal, fish oil and other proteins and oils including soya. They have a low requirement for fish oil, but higher for fishmeal. As it cannot be verified that prawns in these systems are using a certified feed source, or are indeed certified to any independent production standards, we are assuming a standard prawn feed is being used with traceability to ingredient level and responsible sourcing at feed mill. A mean food conversion ratio is used for this species.

Environmental Impacts

Criterion score: 8 info

King prawns farmed in a recirculating aquaculture system (RAS) have little environmental impact. They can be built and operated anywhere and tend to utilize previously existing buildings, thereby avoiding sensitive habitats. When purpose-built, this is done on previously converted land and therefore there is no loss of habitat or loss of ecosystem functionality. As the system is completely closed, there is also no depletion of freshwater supplies as water is only used to top up due to evaporation.

Pathogens are an ongoing challenge in RAS systems due to their rapid spread within the system. However, the inherent design of RAS systems means that there is physical isolation from the surrounding environment. This means that there is no risk of the spread of pathogens or parasites to wild species. This also means that there is no environmental impact from chemical usage. Chemicals are not widely used in UK RAS prawn farming and any wastewater leaving the facility has the ability to be treated and sterilized prior to discharge, indicating that the risk of active chemical compounds being released into the environment is very low. For waste produced, biofilters can also transform any uneaten food/animal waste into fish food, making it almost waste free.

Juveniles used are hatchery produced. They are imported from hatcheries based in the United States and therefore, are not depleting wild stocks. As they are farmed in a closed system, there is no risk of escapes and no measures are needed to control predators.

Fish Health and Welfare

Criterion score: 1 info

Animal welfare is not applicable for crustaceans as it is not covered by EU regulations on welfare. Humane slaughter has been carried out by RSPCA definitions.


Criterion score: 3 info

Land based recirculation systems score well for regulation and management. Marine spatial planning is not applicable to land based systems that are subject to terrestrial planning. There is regulatory framework that covers the protection of valuable habitats and species. As the system is fully closed, regulations regarding EIA, land and water resources, chemicals, discharges, bio-security and species introduction are not applicable and none of the environmental assessment questions scored negatively due to poor regulation. No certification scheme or AIP/FIP is available for UK RAS prawns.

Production method

Closed land based system

A new development in warmwater prawn farming is the use of land based, closed tank system that uses brackish water.


The king prawn (or whiteleg prawn, white shrimp) belongs to the largest of the prawn and shrimp family, the Penaeidae. It is a native species of the Eastern Pacific coast. Its lifecycle may be divided into 6 stages or phases, from embryo to adult, which it completes in one year. The age of sexual maturity varies from 5 to 7 months. They can live up to 2 years in the wild although farmed prawns are usually harvested at 6 months.


Monterey Bay Aquarium Seafood Watch. 2014. Recirculating Aquaculture Systems (RAS) - Global, All Species. Available at [Accessed on 11.11.2019].

Seafish. 2015. Responsible Sourcing Guide: Marine Warm Water Prawns. Available at [Accessed on 12.11.2019].

Pauly, Daniel and Watson, Reg. 2009. Spatial Dynamics of Marine Fisheries In: Simon A. Levin (ed.) The Princeton Guide to Ecology. Pages 501-509. Available at [Accessed on 03.09.2019].

FloGro Fresh. 2019. Available at [Accessed on: 11/11/2019].

Great British Prawns Limited. 2019. Available at [Accessed on 11/11/2019].