Acute toxicity of emamectin benzoate (SLICEtm) in fish feed to American lobster, Homarus americanus

Abstract

SLICE™ (active ingredient 0.2% emamectin benzoate (EMB)), a feed premix developed by Schering‐Plough Animal Health for the control of sea lice on cultured salmonids, is registered for use in several countries and is being prescribed on an emergency basis in Canada and the United States. The concentration of EMB in feed administered to farmed salmon ranges from 1 to 25 μg g−1. To determine the acute toxicity of the compound to juvenile and adult American lobster (Homarus americanus), commercial salmon feed was coated with SLICE™ at a range of concentrations and provided to the animals for 7 d in the laboratory. The LC50 is estimated to be 644 μg g−1 (95% CI=428, 1275) for adult lobsters and >589 μg g−1 for stage V and VI juvenile lobsters. The consumption of medicated pellets by adult lobsters decreased significantly with increasing concentration of EMB. Adult lobsters that died during the study had a significantly greater concentration of emamectin B1a in their muscle tissue than those that survived. These results support the conclusion that salmon feed medicated with EMB at the concentrations used by the aquaculture industry is unlikely to pose an acute lethal threat to adult and small juvenile American lobsters.

Horizontal and vertical distribution of sea lice larvae (Lepeophtheirus salmonis) in and around salmon farms in the Bay of Fundy, Canada

“…This approach does have challenges, as some sea lice populations now are starting to show significant signs of resistance to the chemicals controlling their population growth, a trend that is similar to that experienced by the agriculture industry (Agusti et al., ; Burridge et al., ; Carmichael et al., ; Chávez‐Mardones, Valenzuela‐Muños, & Gallardo‐Escárate, ; Denholm et al., ; Espedal, Glover, Horsberg, & Nilsen, ; Helgesen, Bravo, Sevatdal, Mendoza, & Horsberg, ; Helgesen, Romstad, Aaen, & Horsberg, ; Jones, Hammell, Gettinby, & Revie, ; Sevatdal & Horsberg, ; Valenzuela‐Muños & Gallardo‐ Escárate, ). There are also concerns regarding the potential environmental effects occurring within wild species as these chemicals are released into the natural environment (Burridge, Haya, & Waddy, ; Burridge et al., , ; Ernst et al., ; Medina, Barata, Telfer, & Baird, ,; Van Geest, Burridge, Fife, & Kidd, ; Willis, Gillibrand, Cromey, & Black, ). This has driven a search for alternative, non‐chemical‐based strategies to control sea lice such as cleaner fish (Skiftesvik, Bjelland, Durif, Johansen, & Browman, ; Skiftesvik, Durif, Bjelland, & Browman, ; Treasurer, ; Treasurer & Laidler, ), new cage designs (Stien et al., ) and light traps (Flamarique, Gulbransen, Galbraith, & Stucchi, ; Pahl, Cole, & Bayer, ,).…”

Effect of emamectin benzoate on the molt cycle of ovigerous American lobsters Homarus americanus is influenced by the dosing regimen

“…The measured quantity of emamectin benzoate (Table 1) was determined by ETL/Xenos Laboratories (Nepean, Ontario, Canada) using high-performance liquid chromatography (see Burridge et al 2004 Table 2). *Significantly different from the control group (p < 0.05; Kruskal-Wallis analysis of variance, ANOVA, on ranks and Dunn's test).…”

Environmental issues in Chilean salmon farming: a review

“…The potential effect of pharmaceuticals used in salmon farming has been explored in non-target species (mainly metazoan) in recent years (DeLorenzo et al 2001;Burridge et al 2004;Canty et al 2007;Bhanu et al 2011), but our understanding of potential impacts on the structure and functioning of aquatic ecosystems is still poor (Buschmann et al 2006;Burridge et al 2010).…”