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ARS Home » Northeast Area » Orono, Maine » National Cold Water Marine Aquaculture Center » Research » Publications at this Location » Publication #352106
Title: The infection dynamicsof sea lice on sentinel Atlantic salmon in Cobscook Bay, ME

Author
item FREDERICK, CATHERINE - University Of Maine
item BARKER, SARAH - University Of Maine
item Pietrak, Michael
item BOUCHARD, DEBORAH - University Of Maine
item BRADY, DAMIAN - University Of Maine
item BRICKNELL, IAN - University Of Maine

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/26/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: This study set out to understand the infection dynamics of sea lice, Lepeophtheirus salmonis an ectoparasite of Atlantic salmon in Cobscook Bay, Maine. Spatial and temporal patterns of parasite settlement were investigated between June 2013 and June 2015. The infective pressure was assessed on a monthly basis using lice free fish in sentinel cages exposed to natural lice infection for 7 days. Prevalence, parasite intensity and abundance peaked when surface waters were warming in the spring (May-June) and again during the fall (September- November). There were significant differences in prevalence (p = 0.001) and median abundance (p = 0.003) were detected between the 4 sites for most months. Generalized linear mixed models (GLMMs) were used to establish how key abiotic factors influenced total lice counts. The GLMMs identified 2 sites, Pembroke Landing and Broad Cove, that were significantly different from one another in a single model for the bay (p=0.001). Site-specific GLMMs also revealed a positive effect of temperature on lice counts (p = 0.01). Two of the sites, Pembroke Landing (p < 0.001) and Prince Cove (p=0.02), counts were negatively affected by current velocities. Pembroke Landing was significantly different from other sites with the onset of infection in all analyses, with greater abundance and occurrence of infection. Biologically relevant factors, such as temperature, influence infection by sea lice bay-wide. Other factors investigated were found to be site-specific and an improved understanding of these variables could reduce the risk of infection. There is evidence that an eddy dipole south, of Pembroke Landing, acts as a mechanism of physical retention in sea lice transport in that region accounting for the increased lice in that area.