talking points for nature guides
index of concepts
Prawn farming is destructive
updated Dec 2019
if you learn only 3 things about the issue...
Commercial prawn farms can be highly destructive.
Find out where your prawns come from.
Eat less prawns, don't throw prawns away.

Traditional prawn farming is sustainable: In traditional prawn farming, a small prawn pond is created in the mangrove with bunds or a wall of mud and earth. A sluice gate controls the water flowing in and out of the pond. At first, the sluice gate is kept closed so that little prawns that naturally occur in the water can develop within the pond. After some time, the sluice gate is opened and the water is let out of the pond, but a net is placed at the sluice gate to catch any prawns that move out with the water.

Large scale-prawn farming is destructive: The large prawns that we eat often come from prawn farms or are harvested from the wild by trawling or traps. While traditional farming and harvesting methods are sustainable, large-scale commercial prawn farms and prawn trawling are more destructive and unsustainable.

How do large scale commercial prawn farms impact the environment?
  • Destroying large tracks of mangroves and other intertidal habitats to create the farms;
  • Harvesting egg-bearing adults from the wild to provide stock for the farms;
  • Introducing non-native prawns, which requires foreign exchange. These could upset the natural balance if they escape;
  • The prawns are fed with wild caught fish;
  • The prawn ponds are treated with antibiotics, pesticides and water additives to prevent diseases or boost growth.
  • Water from these farms, laden with prawn waste and chemicals, further damage the surroundings;
  • Diseases that develop resistance to antibiotics devastate not only prawn farms but also other aquacultures and marine wildlife; and
  • Saltwater from the ponds eventually seep into groundwater and affects supplies of freshwater to humans and wildlife in surrounding areas.

How do large scale prawn farms impact the local population?

  • These farms are capital-intensive and do not generate jobs for the low income low skill people that live near the mangroves.
  • The farms displace these locals, who previously relied on the mangroves for food and income.

Why should we care that mangroves are lost?

  • Mangroves provide income and food for subsistence coastal dwellers. These families are displaced in such developments.
  • Mangroves are an important part of the spectrum of marine ecosystems that extend to reefs. Many commercially important fish and other seafood spend their younger days in the shelter of mangroves.
  • Mangrove protect the land from events such as tsunamis, cyclones and high waves. The destruction of mangroves for shrimp farming is believed to have aggravated the impact of the Indian Ocean Tsunami of Dec 04.

What about prawns caught by trawling?

  • Dragging large heavy nets repeatedly over shallow areas. This damages everything on the sea bottom and has been equated to strip mining the reefs and shores. Recovery of the habitat can take 1-20 years.
  • An enormous waste: commercially valuable prawns often make up only 10% of what is caught, the rest is thrown back often dead. In some estimates, for every 1kg of prawns caught, 9-12kg of 'by-catch' are thrown away, amounting to 55 000 tonnes of discards every year. The 'by-catch' includes juvenile fishes and sea turtles.
  • Trawling is seen by some to be a key cause of the decline of some sea turtle species.

So what should we do about eating prawns?

  • Find out where your prawns come from.
  • Tell your supplier and supermarket you prefer prawns from sustainable sources.
  • Eat less prawns.
  • Eat what you take. Don't throw away prawns! (or any food for that matter). Many marine animals have died and people have suffered to put that prawn on your plate!

Status and threats: Some of our shrimps and prawns are listed among the threatened animals of Singapore. However, like other creatures of the intertidal zone, they are all affected by human activities such as reclamation and pollution. Trampling by careless visitors and overharvesting can also have an impact on local populations.

Links References
  • Ong, Jin Eong & Gong, Wooi Khoon (eds.), 2001. The Encyclopedia of Malaysia (Vol. 6): The Seas Didier Millet, Malaysia. 144 pp.
links | references | about | email Ria
Spot errors? Have a question? Want to share your sightings? email Ria I'll be glad to hear from you!
wildfactsheets website©ria tan 2008