Research Document - 2008/049

Abundance-Based Index Assessment Options for Dungeness crab, (Cancer magister) and Spot Prawn, (Pandalus platyceros)

By K.H. Fong, and G.E. Gillespie

Abstract

Allocation issues are especially prevalent for Dungeness crabs (Cancer magister) and prawns (Pandalus platyceros) because they are economically and socially important species. Periodically, Department of Fisheries and Oceans (DFO) resource managers in the Pacific Region receive undefined requests from First Nations for improved access to shellfish for food, social and ceremonial purposes. In most cases, there is little information available on local stock abundance to guide decisions and often, requests are met through effort limitations of the commercial fishing industry such as commercial area closures, seasonal closures or gear limitations.

Canada, British Columbia (B.C.), and First Nations are working to develop treaties, which clearly define the rights for First Nations, via a negotiation process. Numerous First Nations have expressed interest in abundance-based allocations for Dungeness crab and prawn species; however, the current management and assessment frameworks for Dungeness crab and prawn fisheries in British Columbia do not rely on abundance estimates and the data to support an abundance-based approach are lacking.

This paper evaluates the utility of historical catch as a means for delivering allocations for Dungeness crabs and prawns. We also describe fishery dependent and fishery independent CPUE (catch per unit effort) as indices of abundance and describe how allocations can be delivered from abundance indices for Dungeness crabs and prawns. Other abundance estimation models such as change-in-ratio, index-removal, mark-recapture and video assessment are presented.

For comparative purposes, we reviewed the Washington State models for allocation of Dungeness crab and prawn resources.

We conclude that historical catch information for Dungeness crabs and prawns are incomplete. We also conclude that final determination of the most successful approach will depend largely on the spatial scale, stock characteristics, dynamics of each fisheries sector, testing of assumptions and cost.

We provide the following recommendations:

1. Improve and develop catch monitoring programs for all Dungeness crab and prawn fisheries (commercial, recreational and First Nation FSC).
2. If abundance-based index methods are considered, then multiple programs should be initiated, developed and tested to determine which methods are most appropriate in each area prior to implementation of treaties.

Complete document (PDF, 452 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.