Sea lice infestations are one of the most significant welfare challenges in farmed salmon production. Control methods vary widely in their impacts on fish welfare.
Sea lice are a persistent challenge that creates difficult welfare trade-offs in salmon farming. Untreated infestations cause chronic suffering through tissue damage and physiological stress, but many treatment methods themselves carry welfare costs. Mechanical treatments like hydrolicer use water pressure that can injure fish, while chemical treatments stress the animals. The welfare of cleaner fish used as biological control is often overlooked entirely. A welfare-centered approach requires evaluating all control methods against their animal welfare impacts.