Risk from Diarrhetic Shellfish Toxins and Dinophysis to the Australian Shellfish Industry
Optimising the collection of relative abundance data for the pipi population in New South Wales
Long-term information on the abundance and size structure of pipi stocks in NSW is needed to support new management arrangements for the pipi component of the Estuary General fishery. This will provide data that can be used to assess how successful management measures have been at rebuilding stocks and maintaining sustainable levels of harvest. It will also be useful as input information in modelling exercises that may be used in the future, particularly if output controls are used in managing the fishery. Catch per unit effort (cpue) data is not a reliable measure of relative abundance for pipis because the species forms dense aggregations so that catch rates can remain high whist abundance on a beach is actually declining. Also, the unit of fishing effort may not be standard and catches may not be representative of all sizes of pipis so that estimates of spawner and recruit abundance are biased. Further, it can be difficult for industry to sample the whole population such that abundances outside fished areas and sizes of pipi clumps remain unknown. Therefore, it is important that a fishery independent strategy be developed to verify patterns from fishery dependent sources and to collect information on those life stages of the pipis not representatively sampled during normal fishing operations. Combining the expertise of fishers with the use of non-selective sampling equipment provides the best opportunity to develop a cost-efficient fisher-independent strategy. Adopting a collaborative approach which incorporates information from fishery-dependent and independent sources gives the best chance of developing an overall cost-efficient sampling strategy. It s important that fishers be included in all aspects of the survey strategy so that they are familiar with the data collected, have confidence in the stock assessment, and are comfortable in discussing management options.
Final report
Developing clam aquaculture in Australia: a feasibility study on culturing Donax deltoides and Katelysia sp on intertidal and subtidal leases in South Australia
The need for development of an Australian clam aquaculture industry comes from the fact that a large international market is prepared to pay a premium price for quality Australian clams, demand cannot be met by the wild fishery, and clam aquaculture has been successfully developed on a large scale overseas.
CCPL and other cockle fishers are finding that further expansion of their businesses is severely limited by the level of wild catch and as such are actively exploring aquaculture, the basis of this project proposal, to realise the potential of the markets they have developed. Their level of commitment is demonstrated by their contribution of $75,000 cash and $51,160 in-kind towards this project.
We believe that the potential viability of a clam culture industry compares well with the South Australian oyster industry:
- the price per kilogram is as good or better than for oysters;
- stocking levels are likely to be much higher per unit area of a lease, or per cylindrical basket on a longline;
- infrastructure costs are likely to be less if cultured in the sediments, or similar if using a longline system;
- handling, including rumbling and grading are likely to be less frequent; and
- the development of a clam culture industry is likely to occur in a shorter time frame due to the technical, biological and resource management experience gained from the shellfish industry.
Intertidal waters currently identified as being suitable for oyster culture are fully allocated in South Australia and the opportunities for growers to increase business revenue are limited. Clams can offer a new income stream from the same leases, from leases that have proven to be unsuitable for oyster culture, and from new areas.