Multivariate evaluation of the effectiveness of delousing treatment efficacy of azamethiphos (Salmosan®) against the salmon louse (Lepeophtheirus salmonis) in Atlantic salmon (Salmo salar) using wellboat, skirt and tarpaulin treatment modalities

• Published in: Aquaculture Vol. 450; pp. 301 - 307
• Main Authors: Whyte, S.K., Jimenez, D., Revie, C.W., Hammell, K.L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2016; Elsevier Sequoia S.A
• Subjects: Aquaculture; Atlantic salmon; Azamethiphos; Effectiveness; Efficacy; Lepeophtheirus salmonis; Marine; Multivariate analysis; Parasites; Salmo salar; Salmon; Salmosan; Sea lice; Topical treatment; Sea lice; Topical treatment; Lepeophtheirus salmonis; Efficacy; Atlantic salmon; Salmosan; Azamethiphos; Aquaculture
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2015.08.009

Sea lice (Lepeophtheirus salmonis) are the most costly parasitic infestation in the culture of Atlantic salmon (Salmo salar) with control strategies relying heavily on the use of a limited number of chemotherapeutants and traditional univariate analytical tools to evaluate and optimize their delivery. Azamethiphos (Salmosan®) is a powerful delousing agent, which has been administered as a topical treatment using three different modalities: skirt-style enclosures, fully-enclosed tarpaulin enclosures and wellboats. In this study, we analyzed and evaluated the efficacy of azamethiphos treatments between these three modalities against PAAM (pre-adult males and females and, adult males) and adult female (AF) stages using a multivariate approach. The exploratory analysis revealed efficacy in the fully-enclosed tarpaulin modality to be 2.2 times greater compared to skirt-style and wellboat modalities; whereas efficacy against adult females in the wellboat modality was two times larger than in the other modalities. Using the multivariate analysis, treatment efficacy in the fully-enclosed tarpaulin modality was greater than the skirt-style modality, but no significant differences were observed between the wellboat and skirt modalities. These results should be interpreted with caution as differences existed in the abundances and proportions of sea lice stages before treatment that may affect the observed treatment efficacies. For an evaluation and comparison of treatment modalities, multivariate techniques offer added advantages over the more traditional univariate methods, in that simultaneous analysis of multiple sea lice stages and any dependencies or correlation between these stages can be effectively addressed. Control of sea lice infestation of Atlantic salmon. •Evaluating efficacy of azamethiphos in three treatment modalities against sea lice•Comparing univariate and multivariate analyses•Greater efficacy against mobile stages is compared to juvenile stages in all modalities.•Reduction in post-treatment is significantly greater in tarpaulins compared to skirts.•No significant difference in efficacy was observed between wellboat and skirts.