Project number: 1998-107
Project Status:
Completed
Budget expenditure: $19,437.00
Principal Investigator: John Stevens
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 28 Jun 1998 - 23 Mar 2000
Contact:
FRDC
SPECIES

Need

Along with a growing international concern over the status of pelagic shark stocks, the by-catch of pelagic sharks in Australia's tuna longline fisheries is a management issue which is rapidly gaining momentum. There is a need to collate available information on Australian stocks which can serve as the starting point of an information base for management, should this be necessary.

Currently there are restrictions on the landing of shark fins by Japanese vessels fishing inside the EEZ unless the whole carcass is landed, but no such restrictions apply to domestic vessels. At present there is only a small demand for pelagic shark meat. There is, however, some recent interest in target fishing for pelagic sharks and this raises issues over the activation of latent effort if suitable markets are developed for the meat. No specific research has been carried out on pelagic oceanic sharks in Australia and nothing is currently known about the level of fishing which the stocks can support. While logbook information on pelagic shark catches is probably of limited value there is a considerable volume of catch and size data collected through the observer program; these data have not been subject to any detailed analysis.

In assessing the impacts of fishing on pelagic sharks in Australia, there is a need for information on movements and stock structure. Some limited tagging of blue and mako sharks has been carried out by the principle investigator in his own time out of Hobart. Some interesting recaptures have resulted such as a blue shark recaptured from Java and mako sharks recaptured near Lord Howe Island. The opportunity now exists to tag pelagic sharks (mainly blue sharks) at minimal expense using observers on Japanese longliners. While results are unlikely in the time frame of this 6 month study, on-going recaptures should provide valuable information for future studies of pelagic sharks.

Pelagic sharks are one of the 1997/98 research priorities for STBMAC under the category of ecologically related species.

Objectives

1. Document the species found in Australian waters and describe their local and broader distributions
2. Document Australian and overseas catch rates and catches
3. Review their biology in terms of productivity, spatial structure, movements and stock structure
4. Review information on population dynamics, stock status, vulnerability to fishing and management of these species from areas where they are fished.
5. Where possible, determine the impacts of fishing on the stocks in Australian waters using logbook and observer catch and effort data
6. Tag blue sharks on Japanese longliners operating inside the AFZ through the observer program
7. Make recommendations for future research on pelagic sharks in Australia

Related research

Industry
Environment
Environment
PROJECT NUMBER • 1998-107
PROJECT STATUS:
COMPLETED

Review of Australia's pelagic shark resources

1. Document the species found in Australian waters and describe their local and broader distributions
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart