Chemicals used in Aquaculture

Presented by- Jyoti Saroj Department.- Fisheries Resource

ManagementCollege of Fisheries, Veraval, Gujarat

Introduction

Chemicals are essential for- Control of pathogens and diseases.

Increased and controlled production of seed in

hatcheries, increased feeding efficiency and

improvement of survival rates.

Production efficiency increased and animal welfare

enhanced

Chemicals used in aquacultureDisinfectants- Hypochlorite(Sodium or calciumhypochlorite)• Used for disinfection of tanks and equipment.• Chlorine decays with time by the action of sunlight and

consumption of chlorine through its oxidation of organic matter. Quaternary Ammonium compounds (Benzalkonium chloride)

• It have detergent and antibacterial activity • Widely used in shrimp ponds• Now only limited use in food fish

Chemicals used in aquaculture Disinfectants(conti.) -EDTA• Added to larval rearing water in some shrimp

hatcheries• Reduce the bioavailability of heavy metals . -Lime• Widely used to neutralise acidity, increase total

alkalinity• Lime applied to the pond bottom during pond

preparation at 100-8,000 kg/ha

•Burnt lime also used (at 50-100 g/m2) in conjunction with ammonium phosphate to kill pests and predators.

Lime applied in pond

Chemicals used in aquacultureFeed additives (Sulfonamides)

– Sulfamerazine and Romet-30• Effective for bacterial infections• 220 mg/kg fish for 14 days.• Some treatments recommend 3 days, fewer

side-effects.– Toxicity may occur -

• Kidney damage (drug crystal formation in renal tubules)

• Clinical signs – bloating/dropsy (stomach full of water)

Chemicals used in aquaculture

Continued-

– Romet-30

• Suggested dose (furunculosis) – 50mg/kg

fish/day for 5 to 7 days

• Also effective for ESC

• Still used in the catfish industry.

Chemicals used in aquaculture

Terramycin (oxytetracycline) – TM50 Effective against gram neg. bacteria and gram

positive bacteria.Recommended dose – 55-83mg/Kg fish/day for

10 days Should not be fed on prophylactic basis!

• Resistance to oxytetracycline can occur in most bacterial fish pathogens

Chemicals used in aquacultureTherapeutants added to water

– Methods• Static bath – most reliable for

raceways/tanks• Constant flow – safe and can be used in most

situations when fish reared in running water

Chemicals Formalin

• Employed as an antifungal agent • Used to control ectoparasites • 15 to 250 ul/l used for fish and crustaceans

Chemicals used in aquaculture

Chemicals (cont.) Potassium Permanganate

• Great for fungus!! • Strong oxidizing agent

NaCl (salt) (uniodized!!)• Most overlooked treatment• Can be very effective• 3% recommended if possible (10-30 min)

Chemicals used in aquaculture

Copper Sulfate (<6.4 mg copper/L water)

– Also called Cutrine

– Algaecide/bactericide/parasiticide

• Effective on scaled fish, but can cause

problems with scaleless fish (catfish).

• Can produce kidney necrosis, destruction

of hematopoietic tissue, increased liver fat

and inhibition of digestive enzymes.

Chemicals used in aquacultureMalachite green

• Global use as an antifungal and antiprotozoal

• Its use is not permitted in the USA and some Southeast

Asian countries.

Methylene blue

• Effective against fungal and protozoan infections

• May also provide protection against nitrite intoxication