ADDITION OF A SELECTIVE BREEDING PROGRAM FOR RESISTANCE TO SEA LICE Lepeophtheirus salmonis (Krøyer 1838) TO EXISTING LINES ATLANTIC SALMON, Salmo salar L., AT THE USDA'S NATIONAL COLD WATER MARINE AQUACULTURE CENTER  

Sea lice are likely the single most economically costly pathogen that has faced the salmon farming industry over the past 40 years. The most recent economic estimates put the annual cost of sea lice at just under $500 million USD in 2006. This is likely an underestimate of the current costs to industry given the increased resistance to various treatment methods. With the rise of resistance to multiple drugs used to treat sea lice, there has been a significant shift in sea lice management away from a dependence on drugs and towards an approach utilizing multiple non-drug and drug based control methods.

One of the non-drug based management methods gaining favor is the incorporation of sea lice resistance into existing genetic selection programs. Such selection has been implemented in existing commercial broodstock programs in Europe. However the restriction in the Northeast US on utilizing only Atlantic salmon stocks of North American origin means these advancements are unavailable to large segments of the US industry. In response, the USDA has begun a comprehensive program to test their family stocks each year and incorporate sea lice resistance into their existing broodstock program. Initial testing reveals a high level of variation between existing families. Selection of broodstock will be based on breeding values with information from phenotypes and genomic markers.