Selective breeding for sea lice resistance in farmed salmon offers a long-term welfare solution to the industry's biggest challenge. Research is advancing rapidly.
Genetic breeding for sea lice resistance represents a fundamentally welfare-positive approach to the salmon farming industry's most significant welfare and economic problem. Rather than repeatedly treating fish with mechanical or chemical interventions that cause acute stress, resistant strains require fewer interventions, experience lower lice burdens, and suffer less from the secondary infections that lice cause. The welfare benefit compounds across the production cycle: resistant fish experience less cumulative stress, lower rates of wound infection from lice feeding damage, and better overall health outcomes. The research itself involves welfare considerations — lice challenge testing requires exposing fish to the parasites they are being tested against — but this is a limited and justified welfare cost for a research objective that could benefit billions of fish in commercial production. Regulatory support and industry adoption of resistance traits is advancing but requires continued investment.