Acute and Sublethal Effects of Deltamethrin Discharges from the Aquaculture Industry on Northern Shrimp (Pandalus borealis Krøyer, 1838): Dispersal Modeling and Field Investigations

Abstract

Pharmaceutical deltamethrin (Alpha Max), used as delousing treatments in aquaculture, has raised concerns due to possible negative impacts on the marine environment. A novel approach combining different scientific disciplines has addressed this topic. Acute (mortality) and sublethal effects (i.e., fitness, neurological, immunological, and oxidative responses) of exposure of northern shrimp (Pandalus borealis) were studied in laboratory experiments. Passive water sampling combined with sediment analyses revealed environmental concentrations. Finally, dispersal modeling was performed to predict environmental concentrations. Ecotoxicological analyses showed mortality in shrimp after 1 h of exposure to 2 ng L–1 (1000-fold dilution of treatment dose), revealing a high sensitivity to deltamethrin. Sublethal effects included induction of acetylcholinesterase and acyl CoA oxidase activities and oxidative impairment, which may be linked to neurotoxic responses. Field concentrations of 10–200 ng L–1 in water (100 m from the pens) and <LOD-0.19 ng g–1 dw in sediment (0–400 m from pens) were measured. Ecotoxicological values were compared with measured and modeled concentrations. They showed that concentrations higher than those causing mortality could be expected up to 4–5 km from point of release, in an area of 6.4 km2, with lethal concentrations remaining up to 35 h in some areas. Hence, the study demonstrates that there is a considerable risk for negative effects on the ecologically and commercially important shrimp.

Conventional Anthelmintic Concentration of Deltamethrin Immersion Disorder in the Gill Immune Responses of Crucian Carp

“…DEL is an insecticide widely applied to treat parasitic infections on the gills of fish species during freshwater culturing [ 5 ]. In practical application, the conventional anthelmintic concentration of DEL immersion on aquatic animals varies in different ranges such as 0.3–0.6 μg/L [ 16 , 17 , 18 ]. However, as a chemotherapy agent, DEL may have potential adverse effects on the external mucosa of fish when used for the treatment of parasitic diseases due to the external mucosa (such as gill and skin) having direct contact with the external environment [ 5 , 11 ].…”

“…After DEL misuse and overdose after administration, mortality and sublethal effects on aquatic organisms including oxidative impairment, neurotoxic responses, immunotoxic effects, and gut microbiota dysbiosis have been observed [ 10 , 11 , 12 , 13 , 14 , 15 ]. Indeed, the aquaculture industry frequently employs a conventional anthelmintic concentration of DEL within the range of 0.3 to 0.6 μg/L [ 16 , 17 , 18 ]. Notwithstanding the evidence previously obtained, which suggests that chronic exposure to low doses of DEL has a disruptive effect on both intestinal health and the intestinal microbiota [ 12 ], insufficient data exist regarding the negative impacts of prolonged exposure to DEL at therapeutic levels on the external mucosal tissue of aquatic organisms.…”

Antiparasitic approaches and strategies in European aquaculture, with emphasis on Mediterranean marine finfish farming: Present scenarios and future visions

“…Particularly, these drugs have the potential to reduce physiological and reproductive adaptive capacity in target and non‐target organisms 144 . The lethal effects of DEL on Northern shrimp ( Pandalus borealis ), 145 copepods ( Acartia clausi , Pseudocalanus elongatus , Temora longicornis , Oithona similis ) 146 and amphipods ( Eohaustorius estuaries ) 123 were in the range of ng/L. As in the case of AZA, the use of pyrethroids cannot be proposed as bath‐antiparasitics in Mediterranean aquaculture, regardless of the positive results associated with their preliminary use against European seabass ectoparasites.…”

Effect of chronic deltamethrin exposure on brain transcriptome and metabolome of juvenile crucian carp

“…For example, the discharge of Del into aquatic environments causes high northern shrimp mortality, and discharged Del can spread several kilometers away and remain in the environment for a long time. 6 Bioaccumulation of Del in wild fish species in the Pearl River has been reported, which poses environmental risks and health effects to humans. 7 Compared to mammalian species, fish lack degrading enzymes, such as carboxylesterase, and are thus more sensitive to the adverse effects and toxicity of Del.…”

“…Despite being considered safe initially, the environmental impact of Del and its toxic side effects on aquaculture animals have gradually drawn research attention recently. For example, the discharge of Del into aquatic environments causes high northern shrimp mortality, and discharged Del can spread several kilometers away and remain in the environment for a long time 6 . Bioaccumulation of Del in wild fish species in the Pearl River has been reported, which poses environmental risks and health effects to humans 7 …”