Pulsed exposure of Northern shrimp (Pandalus borealis) to salmon lice treatments
It is important to find out if discharges of salmon treatment water can explain the losses of shrimp, and in particular egg carrying females, from fishing areas, as reported by Norwegian coastal fishermen. The proposed experiments will provide valuable new information about how a keystone species in the marine ecosystem, the commercially and culinary important northern shrimp (Pandalus borealis) responds to three chemicals used as medicine against salmon lice in Norwegian aquaculture. We will test the commercial medicines: AlphaMax (a.i. deltamethrin, DEL), Salmosan (a.i. azamethiphos, AZA) and Paramove (a.i. hydrogen peroxide, H2O2). Moderate stress to the shrimp may be expected during the procedures. The experiments will focus on the effects of treatments on egg carrying female shrimp. A screening test will be carried out to find sub-lethal concentrations of the treatment chemicals. Once these are established, a series of experiments using multiple pulse exposures of shrimp to the three chemicals will take place. No more than 500 adult shrimp will be used throughout the entire run of experiments. There are currently no effective replacement methods available to avoid the use of shrimp in this complex experimental investigation. The minimum number of shrimp required to achieve acceptable statistical strength will be used. Surviving non-exposed control shrimp will be returned to the fjord at the end of the experimental procedures.
Endpoints at different levels of biological organization will be studied in adult females during the pulsed exposures and recovery periods. There is evidence that the concentrations of H2O2 used in sea lice treatments can cause gill damage (Carvajal, et al. 2000; Fagereng 2016) and decreased respiration rate (Abele-Oeschger, et al. 1997). At the end of the recovery period, tissue damage in the gills and hepatopancreas will be investigated in order to assess long-term effects of oxidative stress (Mezzasalima, et al. 2008). Investigation of swimming behaviour and immobilization is relevant for the AZA and DEL and for H2O2 exposures, as these compounds are known neuro-toxicants (Burridge et al. 2014).
Description of the shrimp larvae experiments can be found in the attached file.
Endpoints at different levels of biological organization will be studied in adult females during the pulsed exposures and recovery periods. There is evidence that the concentrations of H2O2 used in sea lice treatments can cause gill damage (Carvajal, et al. 2000; Fagereng 2016) and decreased respiration rate (Abele-Oeschger, et al. 1997). At the end of the recovery period, tissue damage in the gills and hepatopancreas will be investigated in order to assess long-term effects of oxidative stress (Mezzasalima, et al. 2008). Investigation of swimming behaviour and immobilization is relevant for the AZA and DEL and for H2O2 exposures, as these compounds are known neuro-toxicants (Burridge et al. 2014).
Description of the shrimp larvae experiments can be found in the attached file.