Research Document - 2015/072

Physical containment approaches to mitigate potential escape of European-origin Atlantic salmon in south coast Newfoundland aquaculture operations

By C.J. Bridger, D.W. Fredriksson, and Ø. Jensen

Abstract

Escapes from aquaculture operations affect the fish farm operator through a loss of potential profits and negative public perception that can generally affect the marketability of farm raised products. Land-based freshwater production hatcheries are essential to the grow-out cycle but are not entirely free of escapes. The vast majority of escapes occur from marine fish farm installations that experience energy on a continual basis from ocean surface currents, wind-driven waves that frequently occur but with higher energy during storms, and tidal currents that affect all aspects of the deployed farm infrastructure regardless of depth. Escapes from marine Atlantic salmon aquaculture operations may occur following structural failures of the net pen and mooring components, operational/management failures during routine fish handling and farm management procedures, and biological failures that include successful predator attacks and vandalism. The first line of defence to minimize any negative effects due to escapes must include all feasible mitigation strategies to prevent the occurrence of escape from the farm operation. Evaluating specific mitigation measures to calculate return on investment to mitigate risks is difficult as often many of these measures cannot be isolated within the very integrated fish farming system. However, specific mitigation measures may be more broadly presented within a short list of high level recommendations including:

• Consideration should be given to whether Codes of Containment should become mandatory within jurisdictional legislation and a condition of the appropriate approval to operate or the aquaculture license. Furthermore, regulatory departments should consider developing an industry standard similar to the Norwegian standard for marine fish farms given the compelling evidence that implementation of the Norwegian standard has resulted in a dramatic decrease in total fish farm escapes throughout its aquaculture sector.
• All existing and potential freshwater and saltwater Atlantic salmon aquaculture sites should be extensively surveyed to collect pertinent information that may contribute to escapes from the operations.
• Selection of appropriate equipment should involve a professional engineer to properly design and dimension all components for the collected site specific data prior to installation of Atlantic salmon fish farms. Deployed equipment should be regularly audited for compliance with the engineered design to ensure proper maintenance continues during use.
• All equipment and operations implemented should include aspects of redundancy, fail-safe design and safety margins for the specific environment to increase the likelihood for full containment of the Atlantic salmon stock throughout the grow-out cycle.
• All operators should ensure that its entire staff is properly trained and understand all standard operating procedures to operate required equipment and facilitate necessary fish handling and farm operations to mitigate fish farm escapes.
• Finally, the Atlantic salmon industry generally remains an innovative sector and this attitude should continue with regards to escape mitigation and might include aspects associated with new equipment (e.g., net pen design, new net materials) and handling procedures.

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