When we talk about the environmental impacts of shrimp farming, we need to first know that fifty-five percent of shrimp produced worldwide are farmed. Crazy right?
Shrimp aquaculture is most common in China, and it has produced significant revenue for these emerging nations. It is also practiced in Thailand, Indonesia, India, Vietnam, Brazil, Ecuador, and Bangladesh.
An enthusiastic, shrimp-loving population in the US, Europe, Japan, and other countries may now get shrimp more easily thanks to farming. Profit-seeking investors have increased the use of industrialized farming procedures, often at great environmental cost.
Traditionally, shrimp farming has been fractionalized, with a large portion of it taking place on small farms in Southeast Asian nations. Governments and development aid organizations in these countries have often promoted shrimp aquaculture as a means of helping those whose income is below the poverty line.
Wetland habitats have occasionally suffered as a result of these laws, in part because farmers can avoid the cost of high-elevation water pumps and ongoing pumping expenses by constructing shrimp ponds close to tidal zones.
Less than thirty years later, many in the shrimp farming industry are still interested in addressing the environmental and social implications, and there has been a revolutionary shift.
In Southeast Asia, Central America, and other regions, both big and small shrimp farms are attempting to produce shrimp in an environmentally friendly manner.
Many want to show that they are adhering to responsible agricultural practices independently by meeting the demanding ASC shrimp requirements.
Over the past three decades, there has been a sharp increase in the demand for shrimp. Shrimp farming increased nine times along tropical beaches in many developing nations between 1982 and 1995, and it has continued to grow ever since.
Many shrimp growers turned to intensive cultivation methods to meet the demand. Intensive shrimp farms consist basically of a grid-like arrangement of separate shrimp ponds. Whether a pond is intended for growing out or for nursery purposes determines its size.
Little shrimp larvae are kept in smaller pools called nursery ponds. The shrimp are moved to grow-out ponds, which are bigger to accommodate the shrimp’s size, once they reach a particular size.
But every pond, no matter how big or small, is connected to a supply canal on one side and another drain canal on the other. Water from a neighboring water source—typically the ocean or a sizable river—is transported into the farm via the supply canal.
The quantity and speed at which water enters and exits the ponds are managed by sluice gates, a kind of sliding gate. The water finally returns to the original water source after exiting the pond through the gate and entering the drain canal.
Aeration, or the mixing of the air and water in the ponds, is facilitated by strategically building the ponds to face the direction of the prevailing wind.
Shrimp farmers provide large amounts of feed to maximize the growth of shrimp raised in intensive farming practices and to meet their nutritional needs. The feed is frequently in the form of pellets.
The three main ingredients of a conventional shrimp diet are fishmeal, soybean meal, and wheat flour, which together supply the protein, energy, and amino acids required for a proper diet.
Up to 40% of the additional feed sinks to the bottom of the ponds uneaten because shrimp nibble rather than consume the entire pellet at once. Due to the high levels of nitrogen and phosphorus in feed, the buildup of uneaten feed in shrimp ponds has a detrimental effect on the ecosystem.
The amount of nutrients in shrimp ponds is greatly increased by the dissolving of uneaten feed. Numerous factors impact the rate of feed pellet breakdown, such as temperature, osmotic pressure, and pH.
Not only does the breakdown of feed pellets raise the concentration of suspended solids in the ponds, but it also releases nitrogen (N) and phosphorus (P) from the pellet as it breaks down. The system gets a considerable amount of these two nutrients because shrimp are expected to not absorb 77% of the N and 89% of the P in the feed pellets.
High levels of dissolved nutrients, particularly phosphorus and nitrogen, cause eutrophication, a form of pollution. Similar to terrestrial plants, aquatic plants also engage in photosynthesis, which depends on these nutrients.
The process by which plants develop is called photosynthesis, and the ecosystem depends on these plants to release oxygen, which is necessary for aquatic life. In a healthy ecosystem, the restricted availability of nutrients regulates the growth of aquatic plants.
But when too many nutrients leak into the environment from man-made sources, such as shrimp farms, the ecology gets too much algae and phytoplankton development. An ecosystem may suffer from algal blooms, which are typically brought on by unchecked phytoplankton development.
One of the most serious consequences of algal blooms is hypoxia, or the depletion of dissolved oxygen in the water. Because aquatic life depends on dissolved oxygen (DO), just like terrestrial life does, the depletion of DO is harmful to these creatures.
The water is cloudy due to the high density of suspended dissolved feed particles and phytoplankton in the water column. Less light thus reaches the water’s lower depths. In competition with the plants on the bottom for light, algae grow above and around them.
As a result, the primary oxygen producers—plants—die from a lack of light. The amount of oxygen released into the water is significantly less when these plants are absent.
To exacerbate the situation, microbes break down the dead plants and phytoplankton. The oxygen used in the breakdown process lowers the water’s DO level even more.
The ecology becomes hypoxic when the bacteria eventually absorb the majority of the oxygen in the surrounding air. Fish that live in hypoxic conditions have severely malformed eggs, smaller bodies, and impaired respiratory systems.
Shrimp and shellfish experience decreased growth, increased mortality, and lethargic behavior. A dead zone results from aquatic ecosystems losing their ability to support life when hypoxia levels are high enough.
Additionally, in a phenomenon known as hazardous algal blooms (HABs), some species of algae release poisonous compounds that can harm other animals. Their quantities are too low to be toxic in typical conditions.
On the other hand, eutrophication permits toxic phytoplankton populations to rise to hazardous proportions. HABs kill fish, shrimp, shellfish, and most other aquatic species when their concentrations are high enough.
Eating food contaminated with poisonous algae can cause serious health problems or even death. Because open-water aquaculture operations consume water from the surrounding environment, they are susceptible to HABs. Red tide can cause large livestock kills if it reaches facilities.
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Environmental Impacts of Shrimp Farming
Although there are many advantages to shrimp farming, the social and environmental patterns of coastal areas are steadily altered. The conflict has arisen from the competition for dwindling coastal resources and the unplanned and unregulated growth of shrimp cultures.
Numerous local, national, and international organizations have tackled the environmental and socioeconomic challenges related to the expansion of shrimp farming in coastal regions.
Research on shrimp production and its effects on the nation’s ecology and socioeconomic conditions is quite limited. Convert from a privately owned, single-function aquaculture system to a multifunctional mangrove ecosystem
The abrupt transition from a privately owned, multifunctional mangrove ecosystem to a single-function, privately owned aquaculture system is one of the primary environmental effects of shrimp farming.
The surrounding soil becomes salted from the seawater from the shrimp farms, making the land unfit for producing trees and other crops. Disease, pollution, sedimentation, and diminished biodiversity are further environmental effects.
Shrimp farming has not only resulted in a loss of livelihood but also in environmental deterioration. Outside investors entered the district and began producing grain on the agricultural lands in the village of Kolanihat in Khulna, a district in southwest Bangladesh.
For this reason, landowners received offers to purchase or lease their property, but they were rarely or never compensated. Similar stories were told in the nearby districts of Bagerhat and Satkhira.
- Destruction of Habitats
- Scarcity of Potable Water
- Outbreak of Disease
- Depletion of Wild Shrimp Stock
1. Destruction of Habitats
In several instances, habitats that are delicate to the environment have been destroyed to make ponds where shrimp are raised. Salt water has also contaminated a few aquifers that supply farmers with water.
Across the world, mangroves have suffered greatly as a result of some types of shrimp cultivation. These mangroves act as storm-effect buffers and are essential to coastal fisheries and wildlife. Whole coastal zones have become unstable as a result of their disappearance, negatively affecting coastal populations.
Shrimp farming can also have an impact on estuaries, tidal basins, salt flats, mudflats, and coastal marshes. For millions of coastal residents, including fish, invertebrates, and migrating birds, these places serve as vital habitats for hunting, nesting, breeding, and migration.
Raising market-sized shrimp takes three to six months in tropical regions, where most farmed shrimp are produced. Many farmers grow two or three crops annually.
Continuous flow of chemicals, organic waste, and antibiotics from shrimp farms can contaminate groundwater and coastal estuaries. Furthermore, salt from the ponds may seep into the agricultural land and contaminate it with groundwater. Long-lasting consequences resulted from this, altering the hydrology that supports wetland habitats.
Trees and other vegetation perish as a result of shrimp farms salinizing and flooding the surrounding area, creating harsher working conditions and less shade. Farmers used to raise an abundance of fruits and vegetables to share with their neighbors before this ecological shift. They can no longer buy produce locally and must fly abroad, with no extra to share.
3. Scarcity of Potable Water
A further factor in the lack of drinkable water is shrimp aquaculture, which forces communities to go several kilometers every day to retrieve drinking water. There are major health repercussions when people gather drinking water during the rainy season and ration it throughout the dry season.
4. Outbreak of Disease
Pathogen introduction has the potential to cause disastrous illness epidemics in shrimp. The shrimp swim on the surface of the production pond rather than the bottom when they are sick with certain infections.
The pathogen is dispersed by seagulls that descend, eat the sick shrimp, and then maybe urinate on a pond many miles away. Disease-related closures of shrimp farms have social repercussions, including job losses.
Two types of shrimp are cultivated for almost 80% of shrimp farmed today: Penaeus monodon (giant tiger prawn) and Penaeus vannamei (Pacific white shrimp). These monocultures are incredibly prone to illness.
5. Depletion of Wild Shrimp Stock
Because the fish stocks employed in the feed formulation for shrimp diets are located close to the base of the marine food chain, they have an extremely high environmental value. Shrimp farmers who gather young wild shrimp to restock their shrimp ponds may further diminish fish populations in the region.
Not just shrimp farming but aquaculture as a whole adversely affects the environment. Also, you cannot compare the nutritional value of a wild fish or shrimp to that of a farm-raised fish. We can see here that the nutrients are in the wild, not the stuff we normally fill our stomachs with, wanting more. Another thing to note here is that we need to cut down on overconsumption.
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A passion-driven environmentalist by heart. Lead content writer at EnvironmentGo.
I strive to educate the public about the environment and its problems.
It has always been about nature, we ought to protect not destroy.