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Environment

Production technology for redclaw crayfish (Cherax quadricarinatus)

Project number: 1992-119
Project Status:
Completed
Budget expenditure: $230,278.00
Principal Investigator: Clive Jones
Organisation: Department of Primary Industries (QLD)
Project start/end date: 21 Nov 1992 - 30 Jun 1997
Contact:
FRDC

Objectives

1. To evaluate the biological characteristics of the recognised stocks of redclaw, determine thier genetic basis and assess their relative suitability to cultivation.
2. To investigate the nutrition of redclaw through studies of digestive physiology/morphology, natural food availability and comparative feeding trials.
3. To develop standard growout techniques in relation to pond preparation, stocking density and size, pond management and harvesting, and to prepare a practical manual for the industry.
4. To investigate the feasibility of polyculturing redclaw and silver perch

Final report

Author: C.M. Jones I.M. Ruscoe
Final Report • 1996-08-06 • 3.47 MB
1992-119-DLD.pdf

Summary

This research and development project aimed to define specific guidelines for the aquaculture production of redclaw crayfish, Cherax quadricarinatus. This aim was achieved, and a comprehensive list of such guidelines is now documented.

Redclaw crayfish aquaculture was a small industry when this project was initiated, generating less than 40 tonnes of product per year. Production technology was undefined and extremely variable across the industry. Now, in 1996, production has risen to around 100 tonnes and a more consistent and appropriate approach is applied to production. This is due to a large extent to the technologies developed by this project, the full benefits of which are still flowing to industry.

Armed with a ‘best practice’ approach, the redclaw aquaculture industry is poised for significant expansion, which will enable it to more fully exploit the excellent export opportunities which have been clearly identified for the product.

A study of the sand crab (Portunus pelagicus) and its exploitation in a sub-tropical multi-sector fishery

Project number: 1984-023
Project Status:
Completed
Budget expenditure: $0.00
Principal Investigator: Mike Potter
Organisation: Department of Primary Industries (QLD)
Project start/end date: 28 Dec 1986 - 31 Dec 1986
Contact:
FRDC

Objectives

1. Compare, contrast life history parameters of sand crab in sub-tropical sth Qld vs. Gulf of Carpentaria & temperate waters.
2. Assess Moreton Bay sand crab stocks
relative impact of recreational, otterboard trawl & commercial crab pot fisheries
effectiveness existing mgt strategies & alternatives

Final report

Author: M.A. Potter W.D. Sumpton
Final Report • 1986-12-31 • 1.77 MB
1984-023-DLD.pdf

Summary

Based on logbook records the sand crab commercial pot fishery in Moreton Bay is worth in the vicinity of $2 million wholesale annually. Sand crabs are also taken as an incidental by-catch by otter trawlers and in addition Moreton Bay supports a substantial recreational fishery.

Sand crabs are caught throughout the year but fishing effort is greatest from October to June. Peak catches in the pot fishery occur during March and April when daily catch rates may exceed 3 legal males per pot. Gravid females are present throughout the year but the highest proportion of egg bearing females is found in the population during August and September. Peaks in mating activity occur in autumn and spring with recruitment of juvenile crabs commencing in November. The parasitic barnacle Sacculina granifera infects 3% of all sand crabs in Moreton Bay and a previously unreported microsporidian parasite is found in 0.7% of the population.

Tagging studies show that fishing effort and mortality of sand crabs is highly variable throughout the Bay. Recapture rates for different areas vary from 1% to 65% with an overall return rate of 14%. The pattern of tag returns does not indicate any ordered directional movement of crabs either into or out of the Bay.

Male and female sand crabs exhibit differences in preferred habitat. Large males are generally more abundant in deeper water, whereas females predominate in shallower water, particularly on the top of sand banks.

Management recommendations arising from the project work include a change in the method of sand crab measurement to the width at the base of the antero-lateral spines, lowering of the existing size limit, the introduction of a bag 1 limit for recreational fishermen and an abolition of the prohibition on taking females provided that suitable management conditions can be maintained.

Environment
Industry
PROJECT NUMBER • 1998-221
PROJECT STATUS:
COMPLETED

Impoundment stocking strategies for eastern and northern Australia

Fish stocking is a valuable and widely used fisheries management tool. If managed well, a fish stocking program can improve the status of declining or threatened fish stocks, restore species diversity to a degraded waterway, and even create a fishery where there was none before. The positive image...
ORGANISATION:
Department of Primary Industries (QLD)
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