Question

Discuss the usage of pesticides in aquaculture and the issues caused by their usage.

Answer 1

Pesticides/ Chemicals used in aquaculture:

• The aquaculture operations will have a demand for chemicals.
• These are used for pond maintenance, spawning aids, disease prevention, fish health management, for controlling unwanted fishes as well as other harmful aquatic animals, pond preparation and water quality management.
• The major chemicals that are usually applied are Organophosphate, Carbamates, Organochlorine, Pyrethroids, and Necotenoides.
• The chemicals used in this regard are lime, slaked lime or unslaked lime, active iodine or potassium permanganate, sodium chloride, formalin, malachite green, methylene blue, hydrogen peroxide and glutaraldehyde.
• The drugs like geotox, green zeolite, zeolite, zeocare, mega zeo, bio aqua, gastrap, aquanone, zeo-fresh, zeo prime are used.
• Glyphosate-based herbicides are used globally to control aquatic weeds.
• Chlorine is an effective treatment for disinfecting hatchery tanks.
• Chlorination has practiced widely in aquaculture for disinfection of holding and rearing tanks for fish.
• Chlorine compounds are applied to puddles of water in the bottoms of empty ponds to eliminate wild fish before refilling ponds.

Issues caused by the use of Pesticides/ Chemicals in aquaculture:

• In recent years, the usage Glyphosate-based herbicides has increased tremendously and is likely to impact on non-target organisms in the environment.

• Spraying herbicides to kill all aquatic plants results in severe low oxygen levels and the suffocation of fish.
• Use of herbicides to completely clean up a pond will significantly reduce fish habitat, food supply, dissolved oxygen and fish productivity.
• Some long-term exposures of chemicals cause abnormalities or mutations in developing fish larvae.
• Acute exposure of chemicals cause immediate fish die-offs.

• Usage of pesticides alter both physical and chemical properties of water such as oxygen carrying capacity, turbidity, pH of water, effects growth, reproduction, movement, malfunction of organs such as eye and kidney.
• It also disturbs the normal distribution and also causes changes in behavior of aquatic organisms.

 Conclusion:

• It is concluded that although chemicals and drugs will continue to play an important role in the development of aquaculture.
• They must be used with caution to avoid adverse effects such as environmental damage and the development of resistant strains of pathogens.
• To minimize the chemical usage, additional emphasis needs to be placed on developing good management practices for aquaculture systems. 

 

Definition of Pesticide:

• Pesticides are the substances which are meant to control the pests.
• Pesticides includes herbicide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide and  lampricide.
• Aquaculture has been practiced in India in both freshwater and coastal saline waters.
• Many chemicals are being used to treat diseases of cultured aquatic animals and also to improve water quality in culture facilities.
• Now a days, usage of chemicals has also increased, particularly in marine shrimp culture.