Sea Lice & Disease

Sea lice and disease outbreaks are the most pressing environmental and economic challenges of aquaculture. Sea lice, or parasitic copepods, feed on the mucus, skin, and blood of fish. They cause painful lesions, scale loss, stress, and secondary infections. These infestations compromise fish health, stunt growth, and in severe cases, lead to mass mortality. The high stocking densities in aquaculture facilities create ideal conditions for rapid lice transmission and disease spread, intensifying the problem.

Treatments to manage sea lice and disease carry significant environmental costs. Chemical pesticides, widely used to kill sea lice, are toxic to marine life and persist in the surrounding water. Their overuse has led to the development of resistant lice strains, rendering treatments increasingly ineffective. Similarly, frequent use of antibiotics to combat bacterial infections raises concern over antibiotic resistance, which can spread to wild fish and harm human health.

Disease transmission from farms to wild populations is another major issue. Farmed fish often live along wild migration routes, allowing infective sea lice larvae and pathogens to pass between populations. Waste and untreated discharge from farms exacerbate the spread of parasites and disease into marine ecosystems. Infected wild fish, especially juveniles, may suffer lethal impacts from low lice exposure.

While biological controls such as cleaner fish offer promising alternatives, they are not widely adopted. Economic losses from disease management and production threaten the aquaculture industry without systematic changes. Current disease and parasite control practices threaten fish farming and the health of the surrounding ecosystem.