Shrimp and tsunamis


December 13, 2012

Industrial shrimp aquaculture is one of the main reasons for the destruction of coastal mangrove forests. These wilderness areas act as a natural buffer against stormy weather. Areas with intact mangrove zones suffered fewer human deaths due to the Dec 2004 tsunamis.

The tsunami disaster that occurred in the Indian Ocean is beyond comprehension – over 200,000 people dead, scores more injured, and massive destruction. Earthquakes and tsunamis are unavoidable, but the severity of this disaster could have been greatly lessened had healthy mangrove forests and coral reefs been conserved along these now devastated coastlines. Instead, these vital protective buffers known for reducing flood and storm damage, have been uprooted for unsustainable developments such as industrial shrimp aquaculture, tourism and urban expansion.

Like other supposedly “natural” disasters – mudslides after torrential rains or drought and desertification in Africa – there’s a human-made element, according to Meyer Brownstone, former chair of Oxfam Canada and Oxfam International (as reported by NOW Magazine, Jan. 13, 2005).

Brownstone used to manage a project on Sulawesi Island off the coast of Indonesia. Sulawesi was one of the places devastated by the recent tsunamis. During the 1990s, coastal mangrove forests still served as a windbreak that protected coral reefs, and cushioned the force of battering storm waves. Those mangrove forests, habitat over millennia for fish and other wildlife, have since all been dynamited and bulldozed to make way for shrimp farms.

The world’s addiction to cheap shrimp “destroyed nature’s protective barrier,” Brownstone says.

Mangroves buffer wild weather

There is scientific evidence that shows that a 15 meter tsunami wave’s destructive force is greatly dissipated as it passes through intact, healthy coastal zones containing coral, sea grass and mangroves. Coastal wilderness acts as a buffer and greatly reduces soil erosion.

According to a report from India, “When the tsunami struck India’s southern state of Tamil Nadu on 26 December… areas in Pichavaram and Muthupet with dense mangroves suffered fewer human casualties and less damage to property compared to areas without mangroves….’

Several reports have verified that fewer losses of life and property occurred in mangrove zones. In many places where the devastation was greatest, mangroves were gone.

In October 1999, mangrove forests reduced the impact of a ‘super-cyclone’ that struck Orissa on India’s east coast, killing at least 10,000 people. But, human settlements located behind healthy mangrove stands suffered little, if any, losses.

In 1960, a large tsunami hit the coast of of Bangladesh. There was not a single fatality. Yet in 1991, thousands of people were killed when a tsunami of similar magnitude hit the same area. Why the difference? Shrimp farms had destroyed all the mangrove swamps between 1960 and 1991.

Mangroves under threat

Over half the world’s mangrove forests have been lost. Less than 16 million hectares remain on coastlines that were once lined with thick stands of resilient mangroves.

Malam Sambat Kaban, Indonesia’s forestry minister, says that his country has lost about 1.6 million acres of mangroves over the past several decades — or about 30 percent of its total — to commercial fish farms and other development.

Mangroves are one of the world’s most important ecosystems, only exceeded by tropical rain forests and coral reefs. Mangrove swamps areturtle inhabited by migratory birds, sea turtles, manatees, dolphins; and a great number of fish species spend part of their life cycles there. Loss of the mangroves has ironically led to a drop in the wild population of shrimp as their nurseries are lost.

Several endangered species depend on mangroves during part of their life cycle – Olive Ridley Turtle, White-Breasted Sea Eagle, Tree-Climbing Fish, Proboscis Monkey, Dugong and Bengal Tigers.

Mangrove forests also help to protect offshore coral reefs. Their roots filter out the silt that runs off from the land.

Mangrove Action Project is calling on aid agencies and governments to back a plan to re-establish protective mangrove greenbelts. Denuded coastlines, if left unprotected, will bear the brunt of future tsunamis and storms. As sea levels rise, and as hurricane and tsunamis threats mount, extensive mangrove restoration and conservation programs must be supported and undertaken.

Shrimp aquaculture

Over 85% of worldwide farmed shrimp is produced in Asia. Approximately two-thirds of it is exported to Japan and the United States, with the remainder divided among other foreign and luxury domestic markets. Farmed shrimp account for about one-third of global consumption, but production is skyrocketing, rising from 100,000 metric tons in the early 1980s to over 700,000 metric tons in 1995. The industry has an annual retail value of over $20 billion dollars US.

A report by the Environmental Justice Foundation (see link below) has exposed wide-ranging environmental damage that can be directly attributed to shrimp farming.

Photo – illegal mangrove cutting, southeast coast of Thailand

Shrimp farming is destroying wetlands, polluting the land and oceans and depleting wild fish stocks. As much as 38% of global mangrove destruction is linked to shrimp farm development. Global mangrove deforestation rates now exceed those of tropical rainforest.

The farming of shrimp is extremely wasteful – shrimp are fed over twice their weight in wild-caught fish before they are sold. This places enormous pressure on wild fish populations.

Pesticides and antibiotics, harmful to human health, are often added to shrimp ponds, polluting water supplies and poisoning plants and animals.

Threat to human health

The often unrestricted use of chemical inputs, such as antibiotics, pesticides and water additives, combined with the buildup feces and unused feeds on the bottoms of ponds creates a harmful accumulation of toxic effluents. This has led to epidemic shrimp diseases. Some of the antibiotics used in shrimp aquaculture are closely related to those used in human medical treatment – this can lead to the development of resistant strains of human pathogens.

Child labour has been reported from a number of countries. Children either collect shrimp fry, spending long hours in water, or work in processing plants in often squalid conditions.

Shrimp trawling in the ocean

Trawling for shrimp typically involves dragging large, fine nets along the bottom of wild marine ecosystems. 25% of seabed life can be removed in the pass of a single trawl. And up to 20kg of marine life is caught and discarded to obtain just 1kg of shrimp.

All fish nets reel in non-targeted species including seabirds, turtles, seals and dolphins. Biologists calculate that around 27 million tonnes of fish are wasted per year because they are the wrong kind or size. Marine mammals frequently get tangled in fishing gear – a problem that kills 1,000 whales, dolphins and porpoises around the world every day (CP June 16, 2003).

Globally, shrimp fisheries account for a third of wasted ‘bycatch’, yet produce only 2% of seafood. Shrimp trawlers are the greatest threat to the continued survival of sea turtles – currently 150,000 are killed each year.

European shrimp fishing vessels are heavily subsidized and exploit shrimp stocks in some of the world’s poorest countries.

References and more information:

Tsunami Action Alert
Loss of mangrove forests contributed to greater impact of tsunamis!
Mangrove Action Project, January 4, 2005.

When aid’s no help
NOW Magazine, Jan. 13, 2005

Mangrove forests seen as life-savers in tsunami
Indonesia, for one, speeds up replanting after decades of neglect   Reuters, Jan. 24, 2005

Clearly presented information on all aspects of shrimp production from the Environmental Justice Foundation. Includes many photographs.

Tropical Shrimp Farms
Article includes links and references.

The Rise and Fall of the Blue Revolution
Long article on the devastating affects of aquaculture. Many excellent photos.

Shrimp farms ‘harm poor nations’

Filed under: Sustainability