Determination of reduced sensitivity in sea lice (Lepeophtheirus salmonis Krøyer) against the pyrethroid deltamethrin using bioassays and probit modelling

The effect of temperature and fish size on growth of juvenile lumpfish (Cyclopterus lumpus L.)

“…Due to the persistence of re-infections of sea louse, efficient control management strategies are hard to find (McVicar 2004). Today the density of lice is mainly regulated by the aid of chemoterapeutants, but increasing resistance to delousing agents such as avermectins (SLICE ®) (Burridge et al 2010), organophosphates (Salmosan ®) (Fallang et al 2004) and pyrethroids (Excis ®, Betamax ® and AlphaMax ®) (Sevatdal & Horsberg 2003;Burridge et al 2010) is an emerging problem in aquaculture (Jimenez et al 2012).…”

Effectiveness of emamectin benzoate for treatment of Lepeophtheirus salmonis on farmed Atlantic salmon Salmo salar in the Bay of Fundy, Canada

“…Bioassays have been used in New Brunswick (Westcott et al 2008), as well as in other salmon farming regions around the world for monitoring sea lice sensitivity to therapeutic agents (Sevatdal & Horsberg 2003, Sevatdal et al 2005, Bravo et al 2008. Westcott et al (2008) In conclusion, this analysis presents evidence of a reduction in emamectin benzoate treatment effectiveness over time and between geographical locations for the period of time examined, 2004 to 2008.…”

Novel point mutation in the sodium channel gene of pyrethroid-resistant sea lice Lepeophtheirus salmonis (Crustacea: Copepoda)

“…1). The selection was based partially on geography, but also on reports of treatment failure or reduced pyrethroid sensitivity documented by bioassays (Sevatdal & Horsberg 2003). Atlantic salmon were netted from cages at the fish farm, and anaesthetized lightly with benzocaine (50 mg l -1…”

“…Since the mid 1990s, the synthetic pyrethroid insecticides cypermethrin ('Excis' and 'Betamax', Novartis) (Hart et al 1997) and deltamethrin ('AlphaMax', Alpharma) have almost completely replaced organophosphates for lice treatments and were used in more than 90% of the treatments in Norway for sea lice in 1999 (Denholm et al 2002). Several clinical treatment failures with deltamethrin and cypermethrin have been reported from Norway (Sevatdal & Horsberg 2000), and reduced sensitivity has been documented using bioassays (Sevatdal & Horsberg 2003).…”