Sources, Quantities and Cultivation Methods
Sources and Quantities
The terms shrimp and prawn are often used interchangeably however in this profile the term prawn is used. The two warm water prawns that dominate world markets are farmed penaeids (i.e. prawn species from the Penaeidae family); namely the Asian, black or giant tiger prawn (Penaeus monodon) and the white leg prawn (Litopenaeus vannamei, known as “vannamei”). Monodon inhabits tropical marine coasts of Australia, South and SE Asia, and East Africa1.
Today warm water prawns are cultured in over 60 countries, and the industry is an important source of jobs worldwide2. Asia-Pacific (China, SE Asia and India) is by far the largest prawn farming region with over 80% of the production, followed by Latin America, which represents around 10%. Other nations including Madagascar, Australia and some in the Middle East make up the remaining 10%3. Farmed warm water prawns are the most valuable of all aquaculture sectors, worth over US$20 billion annually4.
Monodon is cultured across the Asia-Pacific region as the map illustrates. Monodon makes up ~15% of global production of farmed warm water prawns; much lower than vannamei which accounts for ~75%. The remaining ~10% is made up of minor species3. Globally monodon farming was worth some US$5.3 billion from a 2016 total production of some 7o1,801 tonnes4.
Europe is a major market for warm water prawns, with Spain, France, Italy, the UK, Belgium, Germany, and the Netherlands accounting for 90% (€3.3 billion) of the total frozen prawn import value in 20145, 6.
Domestic Market Information7, 8
Warm water prawns are the number one shellfish species in Great British retail (i.e. in England, Scotland and Wales). Although consumers often see all types of prawns as the same, over the past 20 years the consumption of warm water prawns has significantly increased and overtaken that of wild captured cold water North Atlantic prawns such as Pandalus borealis. Warm water prawns such as monodon and vannamei are favoured for their size and meatiness, and perceived to offer better value than smaller prawns.
Warm water prawns were one of the few shellfish products to see market growth during recent periods of financial austerity in the UK. Over the past ten years (from 2008 to 2018), they grew in value and volume by 48.2% and 25% respectively from a base of £185 million and 14,788 tonnes in 2008.
In June 2018, UK retail sales of warm water prawns were worth £307 million (+1.1% compared to the previous year) with a volume of 21,135 tonnes (-2.3%), and an average price £14.52 per kg; ranking as the 4th most popular species by value in the 52 weeks up to 16/06/2018 (including discounters).
In 2018, the UK imported 38,252 tonnes of warm water prawns; the vast majority being frozen.
Note: the difference between the volume of warm water prawns sold in UK retail and that which is imported is due to its use in the foodservice industry (e.g. restaurants) (no data available) and that which is re-exported.
Modern warm water prawn farming began in the 1960s, became a significant industry in the 1990s, and has grown rapidly ever since. Farms are generally located on or near the coast, and use brackish water in their ponds.
Wild monodon spend their post-larval and juvenile stages in coastal estuaries, lagoons or mangrove areas. They migrate to deeper water when they become adolescent and move to spawning grounds as adults. Females produce as many as 500,000-750,000 eggs. Larval stages remain planktonic while tidal currents carry them towards the shore. At this point the young monodon post-larvae become benthic, feeding on detritus, worms and small crustaceans. Traditional pond culture of warm water prawns involved trapping and holding wild post-larvae occurring naturally in coastal zones and this practice continues9.
During the 1970s breeding techniques were developed for some prawn species enabling hatcheries to supply farmers with post-larvae. However, this is generally not the case for monodon, its farming still relies almost entirely on wild stocks10; either by recruiting passively collected wild seed for more traditional production, or the capture of wild broodstock for producing hatchery-reared post-larvae. Wild broodstock are induced to spawn through unilateral eyestalk ablation (removal of one eye) which stimulates the endocrine system and results in ovarian development. However, the mechanism is not fully understood and research continues to find alternative methods.
Although several companies and institutions are developing, or have already developed, fully domesticated monodon stocks11, 12, 13, progress in domesticating monodon (therefore eliminating the industries dependence on wild stocks) lags behind that of vannamei, and broodstock and post-larvae supplies from such sources are still low. Advances in captive breeding on a commercial scale will eventually reduce and eliminate the need for wild collection, and enable supply of disease-free (Specific Pathogen Free or SPF) and disease resistant (Specific Pathogen Resistant or SPR) post-larvae14.
Quality and health status of post-larvae is extremely important as farmed prawns can suffer from several diseases which can cause massive losses, both in production and value. This is perhaps best illustrated by the recent outbreak of Early Mortality Syndrome (EMS) (also knowns as Acute Hepatopancreatic Necrosis Syndrome or AHPNS) and the subsequent slump in global production between 2012 and 201315.
A schematic of modern monodon production is given. Shrimp farms are typically characterised by their intensity level i.e. production per unit area. There are three basic practices: extensive, semi-intensive and intensive pond culture, which represent low, medium and high stocking densities respectively.
- Extensive and Improved-extensive cultivation is carried out using wild post-larvae either entering the ponds on the tide or purchased from collectors, or cultured post-larvae from hatcheries. Extensive ponds are large and fertilised with organic and inorganic fertilisers with a daily water exchange of 10-15%. Stocking density is low and the prawns feed on natural foods (enhanced by pond fertilisation) which are supplemented by artificial diets. Prawn yields are relatively low but polyculture is often practiced and the ‘side-species’ (e.g. mudcrab16) can make major contributions to farmer incomes.
- Semi-intensive cultivation ponds are stocked at moderate densities with hatchery produced post-larvae. Water exchange is regularly carried out by pumping and aerators are used to maintain dissolved oxygen levels. Supplementary feed is provided by the farmer.
- Intensive cultivation ponds are generally small and they are stocked at higher densities. There is vigorous aeration, and regular feeding. Water exchange is limited, especially where there is risk of disease. When such closed systems are used careful monitoring and management of water quality is required. High production harvest volumes can be achieved.
Many monodon farmers have switched to cultivating vannamei17 although vannamei often commands a lower market price. Advantages of switching can be larger yields produced more quickly and in less saline water, as well as better disease resistance.
- FAO FishstatJ
- AC Nielson
- Benzie, J.A.H., 2009. Use and Exchange of Genetic Resources of Penaeid Shrimps for Food and Aquaculture. Reviews in Aquaculture Special Issue on Use and Exchange of Genetic Resources of Cultured Aquatic Organisms, Vol. 1, Issue 3-4
- Kona Bay
- Cocker, L.M., 2014. Farmed Marine Shrimp in Vietnam. Seafood Watch (in prep)