Terms of Reference

Review and Evaluation of Fishing-Related Incidental Mortality for Pacific Salmon

Regional Peer Review Process – Pacific Region

June 6-7, 2016
Nanaimo, BC

Chairperson: Mary Thiess

Context

Stock assessment methods for Pacific salmon require estimates of total mortality in order to obtain accurate exploitation rate and stock size estimates. Total mortality includes natural and fishing-related causes. The latter is composed of retained catch, plus any incidental mortalities associated with fishing activities. Fishing-related incidental mortality can be accounted for by assessing mortality prior to harvest (e.g. depredated and escaped fish), mortality at time of harvest (i.e. fish—other than retained catch—that are dead upon capture), and mortality post-release (i.e. non-retained fish).

Several issues have been raised with respect to the information currently used to generate estimates of different types of fishing-related incidental mortality, including the variability in the time course to monitor mortality after a fishing encounter, the lack of fishery context-specific information (e.g. water temperature), and the need for an efficient process to incorporate new research as it becomes available. For example, recent research indicates that longer-term (i.e. greater than 24 hours) post-release mortality rates are higher than those currently documented in the Integrated Fisheries Management Plans (IFMPs) based mainly on 24-hour holding studies that were conducted prior to 2001 (Raby et al. 2015). Similarly, recent studies relevant to other aspects of fishing-related incidental mortality have not been incorporated into current estimates of mortality used by DFO Fisheries Management and Stock Assessment.

Improved estimates of fishing-related incidental mortality will reduce the uncertainty in predicting the impacts of different fisheries. An improved understanding of factors that impact fishing-related incidental mortality estimates will aid in post-season accounting of both natural and fishing-related mortality. In addition, the evaluation of all types of non-retention related mortality will improve Canada’s commitment to quantify total mortality in the Pacific Salmon Treaty.

Fisheries Management has requested that Science Branch conduct a review of the available literature pertaining to factors relevant to fishing-related incidental mortality of Pacific salmon and provide recommendations on a process to derive and/or modify current estimates of fisheries-related incidental mortality rates for use in the assessment and management of Pacific salmon fisheries.

Advice arising from this CSAS Regional Peer Review (RPR) process will be provided to Fisheries Management in the form of a Science Advisory Report for their consideration in managing Pacific salmon fisheries, and to Stock Assessment for application in relevant Pacific salmon stock assessments. The recommendations may also be relevant to work conducted by the Pacific Salmon Commission Technical Committees.

Objectives

The following working papers will be reviewed, and provide the basis for discussion and advice on the specific objectives outlined below:

Part A.

Patterson, D. et al. Review and evaluation of fishing-related incidental mortality for Pacific salmon. CSAP Working Paper 2014SAL04a.

1. Identify and discuss potential impacts of key factors that can influence fishing-related incidental mortality for Pacific salmon.
2. Conduct a comprehensive review of the primary and grey literature that contains documented evidence (e.g. mortality rates) of fishing-related incidental mortality for anadromous salmonids.  
3. Identify uncertainties and knowledge gaps in the information that is currently available to inform estimates of fishing-related incidental mortality for Pacific salmon.   

Part B.

Patterson, D. et al. Case study:  A process to derive fishing-related incidental mortality rates for Interior Fraser Coho Salmon.  CSAP Working Paper 2014SAL04b.

4. Provide guidance with respect to a process to derive (or update existing) fishing-related incidental mortality rates (or range of rates) for Pacific salmon by species, gear type, location, and/or other factors deemed relevant to various fisheries (where possible and appropriate).
5. Provide guidance with respect to the future incorporation of new information and research on fishing-related incidental mortality of Pacific salmon.

Expected Publications

• Science Advisory Report
• Proceedings
• Research Documents

Participation

• Fisheries and Oceans Canada (DFO):  Science, Fisheries Management, Stock Assessment and Salmon Enhancement Program staff
• Pacific Salmon Commission Technical Committee members: Chinook, Coho, Chum, Fraser River, Northern Boundary, Transboundary representatives
• First Nations technical representatives
• Commercial and recreational fishing representatives
• Environmental non-government organizations
• Academia

References

Raby, G.D., M.R. Donaldson, S.G. Hinch, T.D. Clark, E.J. Eliason, K.M. Jeffries, K.V. Cook, A. Teffer, A. L. Bass, K.M. Miller, D.A. Patterson, A.P. Farrell, S.J. Cooke. 2015. Fishing for effective conservation: Context and biotic variation are keys to understanding the survival of Pacific salmon after catch-and-release. Int. Comp. Bio. 55(4): 554–576. doi:10.1093/icb/icv088

DFO. 2015a. Pacific Region integrated fisheries management plan, salmon, southern B.C., June 1, 2015 to May 31, 2016.   (Accessed February 18, 2016.)

DFO. 2015b. Pacific Region integrated fisheries management plan, salmon, northern B.C., June 1, 2015 to May 31, 2016.  (Accessed February 18, 2016.)

DFO. 2015c. Pacific region integrated fisheries management plan, salmon, transboundary rivers (Alsek, Stikine, and Taku), April 1st 2015 to March 31st 2016. (Accessed February 18, 2016.)