HABITAT UTILISATION: HOW REDCLAW USE VARIOUS TYPES OF HABITAT.
Proponents: QCFA
Broad Aim: To understand how Redclaw use various types of habitat.
Specific Objectives:
To observe and document crayfish interaction with habitat of various types
(at selected levels of crayfish size and density, light and turbidity):
1) Smooth vs. rough pipes.
2) Solid pipes vs. mesh pipes.
3) Pipes with and without one end blocked.
4) Pipe stacks of various configurations (height, width).
5) Pipes of various diameters and lengths.
6) Prawn mesh of various configurations.
To recommend future direction for habitat development.
To ensure current knowledge is shared within the industry and researchers.
The development of suitable habitat has been identified a critical factor in the success of the
Redclaw industry. An understanding of how crayfish use habitat as a function of pond conditions
will allow better habitat to be used and therefore increase farm productivity.
Methods:
Set up laboratory based tanks under various conditions using selected types of habitat
and record the crayfish behaviour over time.
Analyse results and summarise trends.
Hold workshops on the results.
Resources required:
Tanks, crayfish and various types of habitat, video recording gear.
Expected Outcomes:
An analysis of how Redclaw utilise various types of habitat under selected conditions.
Recommendations of the work required for habitat optimisation.
HABITAT UTILISATIONS AS A FUNCTION OF POND CONDITIONS
Proponents: QCFA
Broad Aim: To understand how Redclaw use habitat as a function of pond conditions.
Specific Objectives:
Methods:
To survey and document conditions in farm ponds.
To observe and document crayfish interaction with habitat of various types under varying conditions of:
1) Light levels
2) Temperature
3) Stocking density
4) Crayfish size
5) Turbidity
To recommend future direction for habitat development.
To ensure current knowledge is shared within the industry and researchers.
The development of suitable habitat has been identified a critical factor in the success of the
Redclaw industry. An understanding of how crayfish use habitat as a function of pond
conditions will allow better habitat to be used and therefore increase farm productivity.
Visit farms and document pond conditions.
Set up laboratory based tanks under various conditions using selected types of habitat
and record the crayfish behaviour over time.
Analyse results and summarise trends.
Hold workshops on the results.
Resources required:
Access to farms, underwater light meter & turbidimeter.
Tanks, crayfish and various types of habitat, video recording gear.
Expected Outcomes:
A summary of pond conditions on farms.
An analysis of how Redclaw utilise selected types of habitat under various conditions.
Recommendations of the work required for habitat optimisation.
Increased knowledge, awareness and interest of habitat by farmers.
REDCLAW HABITAT: LITERTURE SEARCH
Proponents: QCFA
Broad Aim: To understand the current state of knowledge of habitat for crayfish.
Specific Objectives:
Methods:
To summarise research work already published for crayfish.
To track down and summarise any unpublished research work on crayfish
habitat.
To recommend the methodology for further work.
The development of suitable habitat has been identified a critical factor in the success of the
Redclaw industry. Development work should not proceed until the current state of knowledge is assessed.
Conduct a literature search on habitat R&D in Redclaw and similar species.
Contact Don Fielder, David Rouse (USA) and other known researchers to
track down unpublished information.
Resources required:
Access to literature research facilities,
Telephone and face to face access to selected farmers, researchers.
Expected Outcomes:
A collection of available literature, and a summary of the findings,
A summary of unpublished research and contact details of researchers
interested in habitat development.
Recommendations of the work required for habitat development.
AIRLIFT DESIGN
Proponents: QCFA
Broad Aim: To bring rigour to the application ofairlift aeration in Redclaw ponds.
Specific Objectives:
To measure the water transfer rate ofairlifts as a function of:
1) Air injection rate,
2) Air injection depth,
3) Air injection method,
4) Pipe diameter and length,
5) Pipe discharge configuration,
6) Pipe entrance configuration.
To measure the oxygen transfer rate at several airlift configurations.
To generate a best practice manual for airlift operation.
Airlift aeration are of fundimental importance to Redclaw farming with their use now universal.
Of all the equipment on crayfish farms, the design of airlifts always raises the most lively discussion.
All farmers have their pet designs and reasons for these designs but there is little scientific evidence
for all these theories. As the output from farms increase it is predicted that the productivity
of ponds may be limited by airlift performance, and the performance of some current designs are
almost certainly influencing the pond output. Power usage is a significant cost component of farm
operation and efficent design will minimise this cost.
Methods:
Conduct a literature search of current design information.
Set up an airlift in a large tank and measure water transfer rate with various airlift configurations.
Design and conduct a set of experiments to measure oxygen transfer rate.
Apply the knowledge to generate a best practice manual for airlift design.
Resources required:
Large water tank
Instrumentation to measure air and water flows.
Air supply.
Oxygen consumption wherewithal 1.
Expected Outcomes:
Design equations for submerged airlifts.
Best practice manual for airlift design.
Reduced operational costs and improved productivity for redclaw farms.
