Abstract:

In order to study the acute toxicity and explore the safety concentration of methylene blue, copper sulfate and ferrous sulfate mixture(5∶2) and povidone-iodine to juvenile Konosirus punctatus, the acute toxicity test of three fishery durgs to juvenile Konosirus punctatus with body length of (2.68±0.24)cm and body weight of (1.97±0.23)g were investigated at water temperature of (25±0.6)℃, pH value of 7.43±0.33 and dissolved oxygen content>6.56 mg·L^-1. The results showed that the half lethal concentrations(LC₅₀) of methylene blue, copper sulfate and ferrous sulfate mixture(5∶2) and povidone-iodine to juvenile Konosirus punctatus under 24 hours' treatment were 36.282 mg·L^-1, 8.984 mg·L^-1 and 7.004 mg·L^-1, respectively. The LC₅₀ under 48 hours' treatment were 29.577 mg·L^-1, 7.545 mg·L^-1 and 6.551 mg·L^-1, respectively. The LC₅₀ under 72 hours' treatment were 28.199 mg·L^-1, 7.400 mg·L^-1 and 6.031 mg·L^-1, respectively. The LC₅₀ under 96 hours' treatment were 24.613 mg·L^-1, 7.063 mg·L^-1 and 5.900 mg·L^-1, respectively. The safety concentration of methylene blue, copper sulfate and ferrous sulfate mixture(5∶2) and povidone-iodine to juvenile Konosirus punctatus were 2.461 mg·L^-1, 0.706 mg·L^-1 and 0.590 mg·L^-1, respectively. According to the evaluation criteria for toxicity of toxic substances to fish, methylene blue was low toxic drug, copper sulfate and ferrous sulfate mixture(5∶2) and povidone-iodine were medium toxic drugs.

Key words: Konosirus punctatus, fishery drug, acute toxicity test, semi-lethal concentration, safety concentration