Effects of the sea lice bath treatment pharmaceuticals hydrogen peroxide, azamethiphos and deltamethrin on egg-carrying shrimp (Pandalus borealis)

• Published in: Marine Environmental Research
• Main Authors: Frantzen, Marianne, Bytingsvik, Jenny, Tassara, Luca, Reinardy, Helena C., Refseth, Gro Harlaug, Watts, Ellie J., Evenset, Anita
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2020
• Subjects: Pandalus borealis
• Online Access: https://hdl.handle.net/10037/30933; https://doi.org/10.1016/j.marenvres.2020.105007

This study investigated effects of sea lice pharmaceuticals on egg-bearing deep-water shrimp (Pandalus borealis). Both mortality and sub-lethal effects (behavior, embryo development, and reproductive output) were studied for each of three pharmaceuticals alone and in different sequential combinations. The most severe effect was observed for deltamethrin where 2 h exposure to 330 times diluted treatment dose (alone and in sequential application with hydrogen peroxide and azamethiphos) induced almost 100% mortality within a few days after exposure. Similar effects were not observed for hydrogen peroxide or azamethiphos. However, sequential treatment of hydrogen peroxide and azamethiphos (2 h exposure to each pharmaceutical; 500 times dilution) resulted in >40% mortality during the first week following treatment. No sub-lethal effects or loss of eggs in female shrimp could be related to exposure to the bath treatments. Future studies should investigate potential sub-lethal effects at exposure concentrations close to the no-effect concentration.