Date of Award

12-2004

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Wildlife Ecology and Wildlife Conservation

Advisor

James Gilbert

Second Committee Member

Kevin Boyle

Third Committee Member

Frederick Servello

Abstract

Harbor seal (Phoca vitulina concolor) predation has been cited as a major cause of mortality, injury, and escapement at Atlantic salmon (Salmo salar) marine aquaculture sites in the State of Maine. Escapements of farm-raised Atlantic salmon are of particular concern due to the potential for breeding and competition with the endangered wild Atlantic salmon. I documented the nature and frequency of seal predation at finfish aquaculture facilities in Maine and whether the severity of seal predation was related to the proximity of farms from one another and nearby harbor seal haul-outs. Managers at operational M s h aquaculture facilities in Maine were surveyed annually from 2001 - 2003 and asked specifically about farm management techniques, husbandry practices, predator deterrence methods employed, and predation. Aerial surveys documenting harbor seal haul-outs along the Maine coast were conducted concurrently. Empirical estimates from generalized linear models, using a negative binomial distribution for the random component, suggest the importance of maximizing the distance between farms and neighboring harbor seal haul-outs and minimizing the number of surrounding harbor seal haul-outs when attempting to deter seal predation at marine salmon farms in Maine. This study further highlighted the ineffectiveness of Acoustic Harassment Devices (AHDs) and the need for Where investigation into the effectiveness of different pen types and predator nets at deterring seal predation.

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