DOI: 10.1577/T04-133.1 Nonlethal Assessment of Juvenile Pink and Chum Salmon for Parasitic Sea Lice Infections and Fish Health

Abstract.—Industrial salmon farming has been corre-lated with infestations of parasitic sea lice Lepeophthei-rus salmonis in adjacent wild juvenile salmonids and declines of sympatric wild salmonid populations. Pro-hibitively large financial, human, and logistical resource requirements prevent the implementation of long-term, large-scale monitoring programs to assess the effect of farms on wild salmonids. We report a novel nonlethal sampling procedure for quantifying louse abundances and measures of fish health on wild juvenile pink salmon Oncorhynchus gorbuscha and chum salmon O. keta dur-ing their early marine life history phase. The method significantly reduces the resource requirements of sam-pling programs and provides a desirable nonlethal al-ternative for studying depressed or threatened popula-tions. The simplicity of the protocol facilitates public participation, further decreasing costs while increasing the potential spatiotemporal coverage and resolution of future research–monitoring programs. Industrial salmon farming now occurs sympat-rically across the native and introduced ranges of most anadromous salmonids. Many studies have correlated the presence of salmon farms with in-creased infection levels of parasitic sea lice Le-peophtheirus salmonis on adjacent wild salmonid