Marine shrimp farming

Increasing ecological problems, repeated disease outbreaks, and pressure and criticism from both NGOs and consumer countries led to changes in the industry in the late 1990s and generally stronger regulation by governments.

In 1999, a program aimed at developing and promoting more sustainable farming practices was initiated, including governmental bodies, industry representatives, and environmental organizations.

[3] Wild juvenile shrimp were trapped in ponds and reared on naturally occurring organisms in the water until they reached the desired size for harvesting.

Taiwan was an early adopter and a major producer in the 1980s; its production collapsed beginning in 1988 due to poor management practices and disease.

Technological advances made more intensive practices possible that increase yield per area, helping reduce pressure to convert more land.

Inland shrimp farms have also been tried in some regions, but the need to ship salt water and competition for land with agricultural users led to problems.

Nursing is not absolutely necessary, but is favoured by many farms because it makes for better food utilization, improves the size uniformity, helps use the infrastructure better, and can be done in a controlled environment to increase the harvest.

Prevalent in poorer or less developed countries where land prices are low, extensive farms produce annual yields from 50 to 500 kg/ha of shrimp (head-on weight).

They require an advanced technical infrastructure and highly trained professionals for constant monitoring of water quality and other pond conditions; their production costs are in the range of US$4–8/kg live shrimp.

The feed conversion rate (FCR), i.e. the amount of food needed to produce a unit (e.g. one kilogram) of shrimp, is claimed by the industry to be around 1.2–2.0 in modern farms, but this is an optimum value that is not always attained in practice.

[27] Infectious hypodermal and hematopoietic necrosis (IHHN) is a disease that causes mass mortality among P. stylirostris (as high as 90%) and severe deformations in L. vannamei.

Most such bacterial infections are strongly correlated to stressful conditions, such as overcrowded ponds, high temperatures, and poor water quality, factors that positively influence the growth of bacteria.

[30] With their high mortality rates, diseases represent a very real danger to shrimp farmers, who may lose their income for the whole year if their ponds are infected.

[37] About 75% of the world production of farmed shrimp comes from Asian countries; the two leading nations being China and Thailand, closely followed by Vietnam, Indonesia, and India.

Besides the near-wipeout of P. chinensis in 1993, there were outbreaks of viral diseases that led to marked declines in the per-country production in 1996/97 in Thailand and repeatedly in Ecuador.

In Ecuador, where shrimp farming was a major export sector (the other two are bananas and oil), the whitespot outbreak of 1999 caused an estimated 130,000 workers to lose their jobs.

[49] All of these factors contributed to the slowly growing acceptance by farmers that improved farming practices were needed, and resulted in tighter government regulation of the business, both of which internalized some of the external costs that were ignored during the boom years.

[50] Shrimp farming offers significant employment opportunities, which may help alleviate the poverty of the local coastal populations in many areas, if it is properly managed.

A 1994 study reported a farmer in Thailand could increase their income by a factor of ten by switching from growing rice to farming shrimp.

[66] Mangroves, through their roots, help stabilize a coastline and capture sediments; their removal has led to a marked increase of erosion and less protection against floods.

Mangrove estuaries are also especially rich and productive ecosystems and provide the spawning grounds for many species of fish, including many commercially important ones.

[7] Many of these problems stem from using mangrove land that has high natural pyrite content (acid sulfate soil) and poor drainage.

[71] A joint programme of the World Bank, the Network of Aquaculture Centres in Asia-Pacific (NACA), the WWF, and the FAO was established in August 1999 to study and propose improved practices for shrimp farming.

Still, it was reported in 2012 that one pound of frozen shrimp adds one ton of carbon dioxide to the atmosphere, more than ten times that generated to produce the same weight of beef raised on cleared rainforest land.

Especially in the boom years of the 1980s and 1990s, when the business was largely unregulated in many countries, the very fast expansion of the industry caused significant changes that sometimes were detrimental to the local population.

Conflicts can be traced back to two root causes: competition for common resources such as land and water, and changes induced by wealth redistribution.

[80] With growing experience, countries usually introduced stronger governmental regulations and have taken steps to mitigate such problems, for instance through land zoning legislations.

In some cases, there is a widening gap between the general population and local elites who have easier access to credits, subsidies, and permits and thus are more likely to become shrimp farmers and benefit more.

[84] Land concentrations in a few hands has been recognized to carry an increased risk of social and economic problems developing, especially if the landowners are non-local.

This would be an ideal option for small scale shrimp farmers supplying for their own community as well as creating an independent food source.

A nauplius of a shrimp
Tanks in a shrimp hatchery
Farmers transferring postlarvae from the tanks on the truck to a grow-out pond
Global aquaculture of shrimp and prawn species in million tonnes, 1970–2009, as reported by the FAO [ 17 ]
Marsupenaeus japonicus (kuruma shrimp) in an aquaculture observation tank in Taiwan
From top to bottom: pieces of the carapace of Litopenaeus vannamei ; a harvested healthy L. vannamei of size 66 (17 g ); a dead L. vannamei infected by the Taura syndrome virus (TSV). The color of healthy shrimp is determined by the color of the plankton, the type of soil at the pond bottom, and the additional nutrients used. The white color of the shrimp at the bottom is due to the TSV infection.
Mangrove estuaries provide a habitat for many animals and plants.
Two false-color images show the widespread conversion of natural mangrove swamps to shrimp farms along the Pacific Coast of Honduras between 1987 and 1999. The shrimp farms appear as rows of rectangles. In the older image (bottom), mangrove swamps stretch across the estuaries of several rivers; one shrimp farm is already visible in the upper left quadrant. By 1999 (top image), much of the region had been converted to blocks of shrimp ponds.
Toxic sludge oozing out of the bottom of a shrimp pond of a farm in Indonesia after the harvest. The liquid pictured here contained sulfuric acid resulting from oxidation of pyrite contained in the soil. Such contamination of a pond leads to stunted growth of the shrimp and increased mortality rates; the growth of the plankton is reduced drastically. [ 62 ] Liming can be applied to counteract to some extent the acidification of the water in ponds on acid sulfate soil , [ 63 ] such as mangrove soils. [ 64 ]