Terms of Reference

Environmental Thresholds to Define Management Strategies for Atlantic Salmon Fisheries under Environmentally Stressful Conditions

Regional Peer Review – Gulf Region

March 15, 2012
Moncton, New Brunswick

Chairperson: David Cairns

Context

There is an overall concern for the status of Atlantic salmon under stressful conditions associated with exceptional climatic events. Inseason management measures have been introduced to reduce the impact of recreational fishing on Atlantic salmon during periods of warm water and low water levels. In eastern Canada, there has been an increased frequency of closures of inriver fisheries as a direct result of warm water and low water levels (Chaput et al. 2000; Dempson et al. 2001). Since 1962, there have been four inseason fishery closures in the Miramichi River; 1987, 1995, 1999, and 2001. The closures corresponded to the years with warm water temperatures and extremely low discharge conditions. In many other years, selected pools or locations were closed to angling due to concerns about illegal fishing activities.

The decision to intervene in season should be based on a demonstrated benefit to the resource and the intervention must be timely. There is overwhelming evidence that incidental mortality from catch and release angling increases with water temperatures above 20ºC (DFO 1998; Dempson et al. 2002). Mortality associated with any additional stress resulting from displacement of salmon from cool water seeps, burst swimming, and general unease would be expected to increase with increasing temperatures. To date, the criteria used for management intervention have been adhoc and not pre-defined which leads to delays in management response and reduced benefits to the resource.

DFO Fisheries and Aquaculture Management (FAM; Gulf Region) has requested advice on environmental thresholds for the management of Atlantic salmon fisheries. The specific questions are:

• What environmental thresholds could be used to trigger management actions to open or close Atlantic salmon fisheries?
• Given the size of the rivers (Miramichi and Restigouche), what are the options available for managing Atlantic salmon fisheries during environmentally stressful conditions?

Objectives

The objectives of the science peer review meeting are to address the questions from DFO FAM considering the following:

• Information on physiology / metabolic rates of Atlantic salmon and associations with level and duration of stress (warm water) and probability of survival.
• Possible temperature benchmarks associated with probabilities of mortality (for ex. maximum daily temperature, minimum daily temperature, and combinations with discharge).
• Possible environmental triggers associated with environmental stress on Atlantic salmon.
• Environmental (temperature, discharge/water level) characteristics (spatial and temporal) of the Miramichi and Restigouche rivers.
• Evidence that Atlantic salmon are susceptible to angling during warm water events and levels of mortalities associated with catch and release fishing.
• Evaluation of fishery management options for Miramichi and Restigouche rivers considering the areal extent of the intervention and the frequency and duration of management interventions.
• Identification of uncertainties and other considerations for managing activities associated with environmental stress.

Expected publications

• CSAS Science Advisory Report
• CSAS Research Document(s)
• CSAS Proceedings

Participation

To assist in the review and the drafting of the advice, participation is expected from:

• Relevant DFO Sectors
• Watershed and angling associations
• Aboriginal peoples
• University researchers
• Invited external experts

References

Chaput, G., D. Moore, J. Hayward, J. Sheasgreen, and B. Dubee. 2000. Stock status of Atlantic salmon (Salmo salar) in the Miramichi River, 1999. Canadian Stock Assessment Secretariat. Research Document 2000/004. 85 p.
(http://www.dfo-mpo.gc.ca/csas-sccs/publications/resdocs-docrech/2000/2000_004-eng.htm)

Dempson, J. B., M. F. O'Connell, and N. M. Cochrane. 2001. Potential impact of climate warming on recreational fishing opportunities for Atlantic salmon, Salmo salar L., in Newfoundland, Canada. Fisheries Management and Ecology 8: 69-82.

Dempson, J.B., G. Furey, and M. Bloom. 2002. Effects of catch and release angling on Atlantic salmon, Salmo salar L., of the Conne River, Newfoundland. Fisheries Management and Ecology 9: 139-147.

DFO. 1998.  Effects of hook and release angling practices. DFO Science Stock Status Report D0-03 (1998).