The Acute and Delayed Mortality of the Northern Krill (Meganyctiphanes norvegica) When Exposed to Hydrogen Peroxide

Abstract

Bath treatment pharmaceuticals used to control sea lice infestations in the salmonid industry, such as hydrogen peroxide (H2O2), are released directly into the environment where non-target organisms are at risk of exposure. The aim of this study was to determine the threshold concentrations for mortality of the Northern krill, Meganyctiphanes norvegica, a major component of the north Atlantic marine ecosystem. To assess the lethal effects of H2O2, we carried out a series of 1 h acute toxicity tests and assessed mortality through a 48 h post-exposure period. One-hour exposure to 170 mg/L, corresponding to 10% of the recommended H2O2 treatment, caused 100% mortality and a subsequent acute median-lethal concentration LC50 value of 32.5 mg/L. Increased mortality was observed with time in all exposed groups, resulting in successively lower LC50 values during the post-exposure period. The suggested H2O2 concentrations have the potential of causing negative effects to the Northern krill.

Drug and pesticide usage for sea lice treatment in salmon aquaculture sites in a Canadian province from 2016 to 2019

“…Unlike the other compounds considered in this report, hydrogen peroxide should not at all accumulate in the environment as it splits quickly into water and oxygen, and is therefore considered environmentally benign 37 . However, recent findings document potential short-term toxicity on non-target species present around farms 38 – 40 . We can note that overall chemical input in the environment was reduced in 2019 (not for hydrogen peroxide) and that this trend has not been consistent within the 4 years.…”

Drug and pesticide usage for sea lice treatment in salmon aquaculture sites in a Canadian province from 2016 to 2019.

“…Unlike the other compounds considered in this report, hydrogen peroxide should not at all accumulate in the environment as it splits quickly into water and oxygen, and is therefore considered environmentally benign 37 . However, recent ndings document potential short-term toxicity on non-target species present around farms 38,39,40 . We can note that overall chemical input in the environment was reduced in 2019 (not for hydrogen peroxide) and that this trend has not been consistent within the 4 years.…”

Analysis of spatial conflicts of large scale salmonid aquaculture with coastal fisheries and other interests in a Norwegian fjord environment, using the novel GIS-tool SEAGRID and stakeholder surveys

“…Deformities may ultimately entail increased mortality. Recently, effects of chemical delousing agents used in bath treatments have come into attention (Bechmann et al, 2019;Bechmann et al, 2020;Escobar-Lux, 2016;Escobar-Lux et al, 2019;Escobar-Lux and Samulsen, 2020;Fagereng, 2016;Fang et al, 2018;Frantzen et al, 2019;Frantzen et al, 2020;Parsons et al, 2020;Refseth et al, 2019). Of particular interest for coastal fisheries is the delayed mortality, occurring 2-4 days after the first pulse of exposure to hydrogen peroxide observed in northern shrimp (Bechmann et al, 2019).…”

“…Hydrogen peroxide (H 2 O 2 ) was long viewed as the most environmentally friendly agent as it degrades to water and oxygen, but recent laboratory experiments have shown detrimental effects on non-target organisms (Bechmann et al, 2019;Escobar-Lux et al, 2019;Escobar-Lux and Samulsen, 2020). Similarly, bath treatments like azametiphos and in particular deltametrin have been shown to adversely affect non-target crustaceans (Bechmann et al, 2020;Parsons et al, 2020).…”