Terms of Reference

Science Advice on Methods for Estimating Fishing Mortality for Porbeagle

Regional Peer Review - Maritimes Region

May 30-31, 2023
Dartmouth, NS

Chairperson: Lei E Harris

Context

Porbeagle (Lamna nasus) is a species of mackerel shark in the family Lamnidae. Porbeagle in the Northwest Atlantic Ocean is considered one population. The Northwest Atlantic population ranges from northern Newfoundland and Labrador to New Jersey, and may extend as far south as South Carolina, with mature females ranging farther south to the Sargasso Sea. This species is widely distributed in the Canadian Atlantic, occurring in the Gulf of St. Lawrence, around Newfoundland and Labrador, on the Scotian Shelf, and in the Bay of Fundy. Most of the Northwest Atlantic population is found within Canadian waters at some point in its life history. Porbeagle was first assessed as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in May 2004, and was re-assessed as Endangered by COSEWIC in May 2014 (COSEWIC 2014). Porbeagle Sharks in the Northwest Atlantic are currently being considered for listing under the Canadian Species at Risk Act. Regardless of any listing decision, quantifying bycatch and total fishing mortality will be necessary to implement and monitor management measures for the species, inform fisheries management decisions, and to track recovery. Therefore, DFO Maritimes Region Species at Risk Program submitted a request to DFO Maritimes Region Science to estimate total annual fishing mortality of Porbeagle Sharks.

Objectives

The specific objectives of this meeting to address the request for advice are as follows:

• Estimate the total commercial catches of Porbeagle Shark in the Maritimes, Gulf, Newfoundland and Labrador, and Quebec regions, in both tonnage and number of animals.
• Determine the proportion of Porbeagle bycatch attributed to specific fisheries and retained by each.
• Evaluate the spatial and temporal distribution of bycatch and estimate how it has changed over time
• When bycatch is discarded, estimate post-release mortality for each fishery/gear type
• Describe uncertainties in the estimates of bycatch and mortality and identify gaps in available data sources.
• Explore various methods to address the above objectives, including approaches used in other jurisdictions (e.g., ICCAT, USA)

Expected Publications

• Science Advisory Report
• Research Document

Expected Participation

• Fisheries and Oceans Canada (DFO) Science, Aquatic Ecosystems, and Fisheries Management
• Provincial government representatives
• Academia
• Indigenous communities/organizations
• Fishing industry
• Non-government organization representatives

References

• COSEWIC. 2014. COSEWIC assessment and status report on the Porbeagle (Lamna nasus) in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xi + 40 pp.