Shrimp FarmShrimp Farms and the s and the Environment Environment

Yont MusigYont Musig

Shrimp culture has been expanded rapidly in Asia. Shrimp culture has been expanded rapidly in Asia. Farmed shrimp is now being a major exporting Farmed shrimp is now being a major exporting commodity for several countries, providing job commodity for several countries, providing job opportunity and income for shrimp farmers and opportunity and income for shrimp farmers and other personnel in relating sectors.other personnel in relating sectors.

Shrimp farmingShrimp farming

Rapid expansion of Rapid expansion of intensive shrimp farming intensive shrimp farming without proper planning without proper planning has created various has created various environmental problems. environmental problems. Destruction of mangrove Destruction of mangrove is one of the major is one of the major environmental impact of environmental impact of shrimp farming in several shrimp farming in several countries. countries.

SShrimp farmhrimp farms and mangrove s and mangrove –– Kung Kung KabenKabenBay, ThailandBay, Thailand

SShrimp farmhrimp farms and mangrove s and mangrove –– Kung Kung KabenKabenBay, ThailandBay, Thailand

Low salinity shrimp farming Low salinity shrimp farming in inland areain inland area

Vertical distribution:Vertical distribution:mostly within 15mostly within 15--20 20 cm(maximum 40cm(maximum 40--50 50 cm)cm)

Horizontal distribution:Horizontal distribution:Within 3Within 3--5 meters5 meters

Salt distributionSalt distribution

Low salinity shrimp farmLow salinity shrimp farminging

Shrimp pond effluentsShrimp pond effluentsShrimp pond effluent containing high load of Shrimp pond effluent containing high load of organic matterorganic matter,, nutrientsnutrients, chemicals, and , chemicals, and antibioticsantibiotics also affect also affect the environmentthe environment. .

Chemical and biological productsChemical and biological products

Several chemicals and biological products Several chemicals and biological products used in shrimp ponds can affect the used in shrimp ponds can affect the environment. These substances includenvironment. These substances include e antibioticsantibiotics, , toxic chemicalstoxic chemicals, , and nutrientsand nutrients..

AntibioticsAntibiotics

The release of antibiotics from shrimp The release of antibiotics from shrimp ponds or hatcheries can cause resistance ponds or hatcheries can cause resistance among the pathogens, and a change in among the pathogens, and a change in micromicro--organism population in aquatic organism population in aquatic environment.environment.

AntibioticsAntibiotics

The release of antibiotics from shrimp The release of antibiotics from shrimp ponds or hatcheries can cause resistance ponds or hatcheries can cause resistance among the pathogens, and a change in among the pathogens, and a change in micromicro--organism population in aquatic organism population in aquatic environment.environment.

AntibioticsAntibiotics

Resistance towards some of the antibiotics Resistance towards some of the antibiotics commonly used in shrimp farming, e.g. commonly used in shrimp farming, e.g. chloramphenicol and tetracycline, is chloramphenicol and tetracycline, is already developing in human, as well as already developing in human, as well as shrimp pathogens. shrimp pathogens.

ChemicalsChemicals

Some chemicals released into the Some chemicals released into the environment from shrimp farms can be environment from shrimp farms can be acutely toxic, mutagenic or have other acutely toxic, mutagenic or have other negative effects on aquatic organisms.negative effects on aquatic organisms.Their potential effect on nonTheir potential effect on non--target target organisms depends on toxicity and on the organisms depends on toxicity and on the degradation rate and dispersion.degradation rate and dispersion.

The toxicological mechanisms of pollutants The toxicological mechanisms of pollutants cause different stress levels to different cause different stress levels to different groups of organisms and can potentially groups of organisms and can potentially change the community structure of marine change the community structure of marine sediments.sediments.

The discharge of shrimp pond water The discharge of shrimp pond water treated with teaseed has been associated treated with teaseed has been associated with mass fish kills in adjacent with mass fish kills in adjacent waterwater. . There were There were reportreportss that insecticides such that insecticides such as as DipterexDipterex have been ushave been useded to kill disease to kill disease vectors such as crabs and small shrimps, vectors such as crabs and small shrimps, thus posing a threat to the environmentthus posing a threat to the environment

Some of theSome of the substances substances used in shrimp used in shrimp farmsfarms might have an might have an important important impact on impact on the environment. For example, copper the environment. For example, copper compounds, some organotin compoundscompounds, some organotin compounds, , and certain other substances with a high and certain other substances with a high affinity to sediment affinity to sediment that that leave persistent leave persistent and and toxic residuestoxic residues..

OrganotinOrganotin compoundscompounds

Organotin compounds e.g. triphenyltin Organotin compounds e.g. triphenyltin acetate (Brestan), triphenyltin chloride acetate (Brestan), triphenyltin chloride (Aquatin) were used in south(Aquatin) were used in south--east Asia to east Asia to remove molluscs before the stocking of remove molluscs before the stocking of shrimp pondsshrimp ponds..

NutrientsNutrients

Nutrient input to shrimp ponds by adding Nutrient input to shrimp ponds by adding fertiliser and feed can result in the fertiliser and feed can result in the eutrophication of waters receiving the eutrophication of waters receiving the shrimp pond effluentsshrimp pond effluents..

Environmental impactEnvironmental impact

IIt t is is very difficult to assess the impact of very difficult to assess the impact of shrimp farming chemicals on the shrimp farming chemicals on the environment environment because of the because of the lack of lack of information about the quantities of information about the quantities of chemicals used in shrimp farming. chemicals used in shrimp farming.

Environmental impactEnvironmental impact

It is necessary to collect more information It is necessary to collect more information about the types of chemicals and the about the types of chemicals and the quantities used in shrimp farming. Without quantities used in shrimp farming. Without this, it is impossible to draw any this, it is impossible to draw any conclusions on impact on the environment. conclusions on impact on the environment.

Situation of researchSituation of researchThe literature on degradation and The literature on degradation and environmental effects of aquaculture environmental effects of aquaculture chemicals is dominated by studies on chemicals is dominated by studies on antibiotics.antibiotics.Little is known about the degradation and Little is known about the degradation and environmental effect of these chemicals, environmental effect of these chemicals, especially in tropical environmentsespecially in tropical environments,, and and studies in this field are needed.studies in this field are needed.

Another field that needs to be investigated further Another field that needs to be investigated further is the environmental fate and biological effects of is the environmental fate and biological effects of the substances, more specifically under the the substances, more specifically under the conditions prevalent in marine aquaculture ponds conditions prevalent in marine aquaculture ponds and in a tropical environment. and in a tropical environment.

Eutrophication is often mentioned as an Eutrophication is often mentioned as an important negative impact of shrimp farming on important negative impact of shrimp farming on the environment. However, studies showing the the environment. However, studies showing the connection between shrimp farming, connection between shrimp farming, eutrophication and changes in the ecological eutrophication and changes in the ecological community structure have not been found in community structure have not been found in international journals. Data from such studies international journals. Data from such studies would be very valuablewould be very valuable..

Sustainable culturing technique with Sustainable culturing technique with least environmental effect is also least environmental effect is also needed to be developedneeded to be developed to decrease to decrease the use of antibiotic and chemicals in the use of antibiotic and chemicals in shrimp farming and to decrease the shrimp farming and to decrease the load of organic matter and other load of organic matter and other pollutants in shrimp pond effluents.pollutants in shrimp pond effluents.

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