Biological and fisheries data for managing deep sea crabs in Western Australia

Funded Activity Summary

Since the snow crab is presumably slow growing and long-lived and therefore vulnerable to overfishing, there is a pressing need for collecting baseline biological and fishery data that can be used to produce a preliminary stock assessment for assisting in the management and conservation of this species in Western Australia. Mechanisms for obtaining data on size compositions and catch statistics for the fishery in the early stages of its development need to be established so that the extent to which large animals are depleted as a result of fishing pressure can be determined.

In the early stages of the proposed work, it will be necessary to determine the catch and distribution of the commercial fishery and the size (carapace length), sex ratio and relative abundance by depth of the crabs that form the basis for the fishery. This will enable any future changes that occur in these characteristics as a result of fishing pressure to be detected.

Since snow crabs are expected to have long intermoult periods, it will be necessary to tag crabs as soon as possible to provide, in the relatively near future, information on growth rates, movements, and estimates of yield and eggs (or spawning biomass) per recruit.

Accurate information is needed on the size at which snow crabs first reach maturity and how frequently spawning occurs within a year.

Information is required on the size of gaps in traps that would allow sublegal sized crabs to escape and thereby prevent unnecessary mortality and displacement.

A basic stock assessment is required to meet Environment Australia’s Schedule 4 exemption in the short term and Fisheries WA/Environment Australia requirements whch are to be initiated in December 2002.

Objectives:
1. Implement a voluntary log book system in which fishers will record the number, size and location of capture of crabs and establish the data bases that are necessay to record and maintain logbook, size composition and tagging data.
2. Collect and process biological research data on the size, weight, moult stage, shell state, sex ratio, gonadal weight and gonadal stage of snow crabs caught by commercial fishers at regular intervals during the year.
3. Determine the relative abundance of snow crabs in the various depths and regions in which this species is fished.
4. Determine the patterns of movement, growth and frequency of spawning of snow crabs.
5. Determine the size of snow crabs at first maturity.
6. Determine the effectiveness of the escape gaps currently in use in the fishery in reducing the catch of sub-legal sized crystal crabs.
7. Undertake an experiment to infer short-term movement and changes in density resulting from localized depletion of the fishing grounds.
8. Produce an initial assessment of the status of the snow crab stock on the west coast of WA.

Funded Activity Details

Start Date: 25-07-2001

End Date: 02-07-2007

Funding Scheme: Funding Scheme not available

Funding Amount: $347,674.00

Funder: Fisheries Research and Development Corporation

Research Topics

ANZSRC Field of Research (FoR)

There are no FoR codes available for this funding activity

ANZSRC Socio-Economic Objective (SEO)

There are no SEO codes available for this funding activity

Other Keywords

Fishing Gear | Habitat | Laboratory Procedures | Otolith | Stock Assessment

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