Viability, growth, development, and performance of juvenile sockeye salmon (Oncorhynchus nerka) exposed to neonicotinoid pesticides

The effects of the neonicotinoid insecticide imidacloprid on sockeye salmon (Oncorhynchus nerka) exposed from 1 h post-fertilization to the swim-up fry developmental stage were evaluated using a gravel-bed flume incubator designed to simulate a natural streambed environment. This chronic exposure tested nominal imidacloprid concentrations of 0.15, 1.5, 15, and 150 µg/L to investigate the effects on hatching success and timing, deformity rates and growth. The effects of the neonicotinoid insecticides thiamethoxam, imidacloprid, and clothianidin, and mixtures of all three on burst swimming performance and routine metabolism in sockeye salmon (Oncorhynchus nerka) were also examined after acute 96-h exposures. There was no evidence that chronic exposures impacted growth, development, hatch timing and success or survival in sockeye salmon during the embryonic pre-hatch and post-hatch alevin developmental stages. There was also no evidence that acute exposures to environmentally relevant concentrations of neonicotinoids impacted swim performance or routine metabolism in swim-up fry.