A COMPARATIVE STUDY ON THE TOXICITY OF A NATURAL NEEM OIL AND SYNTHETIC PYRETHROID DELTAMETHRIN, CYPERMETHRIN CHEMICAL ON DAPHNIA (ZOOPLANKTON) IN FISH NURSERIES

Fisheries are a sunrise sector with varied resources and potentials of aquaculture. Carps fishes contribute the large share in the total global aquaculture production. The zooplankton is the best food source for Carp fishes and fish larvae and an important part of the food chain in fish ponds. Zooplankton’s high density is necessary in fish nurseries for the dynamic growth of fish larvae. Indian Major Carps are breed in the rainy season and this time duration aquatic insects are also developed and increase in number in freshwater fish ponds. Same aquatic insects are harmful to fish spawn and fish fry because they are competing with fish food (zooplankton) and heavily predators on fish spawn and fry in freshwater fish nurseries. Mostly chemical-based insecticide is used for the eradication of aquatic insects in fish nurseries but they give deleterious effects on the zooplankton density in fish nurseries and plant - based pesticides are less toxic to zooplankton and fish larvae. Bioassay of a natural insecticide Neem oil and synthetic Pyrethroid Deltamethrin and Cypermethrin were separately done on a Daphnia. This experiment was conducted in 15 glass beaker of 1 litre water capacity and wide range of selected insecticide optimum doses were used for desired time 96 hours till mortality to Daphnia, the static bioassay tests were conducted under the laboratory condition and calculated LC50 and monitored Physico – Chemical parameter of treated water in the experiment. The toxicity test of Deltamethrin LC50 were recorded 0.000030ppm, 0.000028ppm, 0.000026ppm and 0.000023 ppm at 1hr, 2 hr, 3hr and 4hr respectively. In the case of the toxicity test of Cypermethrin LC50 were recorded 0.000016ppm, 0.000018ppm, 0.000015ppm and 0.000013ppm at 1hr, 2 hr, 3hr and 4hr respectively and no mortality observed in Toxicity test of Neem Oil. Neem Oil is origin from Azadirachta indica plant seed and leaf naturally. This study was done to compare the non-target toxicity of a natural pesticide of neem plant origin Neem Oil and Synthetic Pyrethroid Deltamethrin, Cypermethrin Chemical on Daphnia (Zooplankton) in Fish Nurseries and provide a detailed overview of present thinking into the mode of action and effects of Neem oil as an eco-friendly insecticide in fish nurseries.