Terms of Reference

A Framework for the Assessment of Snow Crab (Chionoecetes opilio) in Maritimes Region (NAFO Division 4VWX)

Regional Science Advisory Process – Maritimes Region

February 25-26, 2020
Dartmouth, NS

Chairperson: Tana Worcester

Context

Snow Crab (Chionoecetes opilio, O. Fabricius) is a subarctic species with a distribution from northern Labrador to near the Gulf of Maine. Snow Crab has been a dominant macro-invertebrate in the Scotian Shelf ecosystem since the decline of the groundfish during the late 1980s to early 1990s.  They are observed in large numbers in deep, soft-bottom substrates ranging from 60-280 m water depths and at temperatures generally less than 6 °C. Scotian Shelf Snow Crab are in the southern-most extreme of its spatial distribution in the Northwest Atlantic.

The Snow Crab fishery on the Scotian Shelf has been in existence since the early 1970s. It occurs annually throughout the year dependent upon the Crab Fishing Area (CFA).  In 2005, many CFAs and subareas were merged with the resulting divisions being North-Eastern Nova Scotia (N-ENS; formerly CFAs 20-22), South-Eastern Nova Scotia, S-ENS; formerly CFAs 23, 24), and Northwest Atlantic Fisheries Organization (NAFO) Area 4X.

This meeting will provide an introduction to an operationally viable way of providing a stock assessment for snow crab in Maritimes Region. The proposed approach is an ecosystem-based spatiotemporal one that uses discrete (Conditional Autoregressive) models in a flexible framework to replace the previously used continuous space-time modelling approaches; the latter are no longer operational due to time and computational limits.

Objectives

The objectives of this science advisory meeting are to:

• Review the proposed spatiotemporal modelling approach
• Demonstrate the utility of the proposed models for estimating abundance and for use in future assessments

Expected Publications

• Research Document
• Proceedings

Expected Participation

• DFO Science
• DFO Resource Management
• Aboriginal Communities/Organizations
• Fishing Industry
• Provincial representative
• Non-government organizations
• Other invited experts