Sustainable (biological) control of sea lice in Norwegian Atlantic salmon farms: a system dynamics approach

• Main Authors: Hamza, Kanar, Rich, Karl
• Format: Conference Object
• Language: English; unknown
• Published: International Institute of Fisheries Economics and Trade
• Subjects: Fisheries > Economic aspects > Congresses; Sustainable fisheries > Congresses; Aquaculture: Disease Management; Fisheries Economics; Aquaculture; Norway; Atlantic salmon; Salmo salar
• Online Access: https://ir.library.oregonstate.edu/concern/conference_proceedings_or_journals/bv73c1565

Sea lice (lepeophtheirus salmonis) are a type of ectoparasite that hosts on Atlantic salmon (Salmo salar), weakening the fish and slowing its growth rate. In addition to the direct loses associated with reduced fish growth, sea lice also cause significant economic losses to salmon industries in Norway due to the costs associated with conducting chemical treatments to control sea lice populations. Moreover, chemical treatments can induce mortality in salmon themselves. Biological treatments such as sea wrasse (natural predators that prey on sea lice in farmed Atlantic salmon) are a promising alternative to control lice populations, but their cost-effectiveness vis-a-vis conventional treatment options has not been adequately explored quantitatively. A system dynamics model was developed that looks at the cost-effectiveness of sea wrasse control, taking into account the feedbacks between host-parasite interactions and fish management strategies. Model results showed that using sea wrasse is extremely efficient in controlling sea lice at low levels in salmon farms, which significantly reduced the need of using multiple chemical treatments to control lice populations. In turn, the reduced use of chemical treatments leads to a significant reduction in costs to control sea lice relative to conventional measures. Reducing the dependency on chemicals further benefits the salmon industry through reducing environmental footprints and enhancing the social responsibility of the industry.