1.College of Fisheries and Life Science， Dalian Ocean University， Dalian 116023， China； 2.Engineering Research Center of Shellfish Culture and Breeding in Liaoning Province， Dalian 116023， China
Abstract: Acute toxicity of NO2-N to fertilized eggs and larval yesso scallop Patinopectenyessoensis with shell length of (129.4±14.8)μm， (145.4±7.4)μm and (238.0±47.7)μm was conducted in a 2 L polyethylene tub at water temperature of 15-18 ℃ in order to evaluate the effect of NO2-N concentration on hatching rate of fertilized egg, growth and survival of larvae, and metamorphosis rate of eye-spot larvae. The results showed that the 72 h EC50 of NO2-N was 1.07 mg/L in the fertilized eggs, with the 72 h maximum acceptable toxicant concentration (MATC) of 0.026-0.257 mg/L. The 96 h LC50 was 0.306 mg/L in 129.4 μm planktonic larvae and 3.24 mg/L in 145.4 μm planktonic larvae, with the 96 h effective concentration of relative growth decreased by 5% (EC5) of 0.026 mg/L and MATC of 0.008-0.273 mg/L in 129.4 μm planktonic larvae and 0.076 mg/L and MATC of 0.016-0.291 mg/L in 145.4 μm planktonic larvae. The 216 h EC50 was 5.94 mg/L, with 216 h MATC of 0.699-1.824 mg/L in metamorphic the eye-spot larvae and 216 h EC5 of relative growth was 0.078 mg/L in metamorphosis stage. It was found that small size D shaped larvae had more sensitive to nitrite nitrogen than larger size D shaped ones did. It is suggested that nitrite nitrogen be controlled below 0.030 mg/L for indoor breeding and below 0.080 mg/L for juvenile culture in scallop breeding. The findings provide reference for improving ecology and the water quality control during seedling culture.
2019, Vol. 34 
