The ET&BF is presently dealing separately with a number of ecological issues. For example, impacts of longliners on shearwaters and turtles are current high profile problems. However, other issues such as depletion of swordfish, SBT bycatch, availability of tunas in relation to oceanographic features, bycatch of sharks and finning have all taken centre stage at different times in the short history of the domestic fishery. This approach is often reactionary, rather than strategic, and may not be the best use of research resources over the long-term. If the ET&BF is to move substantially toward ecosystem-based fishery management, as it is required to do under the EPBC act, rather than continue the individual species management approach, an ecosystem analysis providing ecosystem metrics must be developed. If, for example, ET&BF managers opt for time area closures as part of their management strategy to protect key species, developing these on a species-by-species basis has the potential to impact the whole fishery. To develop and evaluate time area closures that allow for minimizing risk of adverse impacts to the suite of key species, while allowing for optimal efficiency of fishing, understanding the associations, linkages and interactions between species is essential. This is the ecosystem approach. Developing an understanding of how ecosystem-associations relate to oceanographic features is also essential in open ocean systems where the dominant influence on distribution and local abundance is oceanography. The approach we are taking will provide the information needed to support an ecosystem-based management framework. Through the analyses we are proposing we will identify regional “hot spots”, detail their linkages and provide detailed scenarios as to how we think different management strategies and fishing practices will or will not impact pelagic food chains, ecologically related non-target species, competitors (e.g. sharks, marlins etc.) and their associated ecosystems. The need for ecosystem-based fishery management for the Western Pacific region has also been supported by PrepCon for the soon-to-be formed WCPFC (Working Paper 9, 2002).
Project number:
2004-063
Project Status:
Completed
Budget expenditure:
$562,357.40
Principal Investigator:
Jock Young
Organisation:
CSIRO Oceans and Atmosphere Hobart
Project start/end date:
14 Apr 2005
-
30 Nov 2008
Contact:
FRDC
1. Identify the spatial extent and the temporal stability of the main ecosystems of the eastern tuna and billfish fishery based on their species composition and physical environment.
2. Define the trophic structure within these ecosystems with emphasis on the relationship between target, bycatch and threatened and protected species.
3. Develop an ecosystem model for the ETBF fishery incorporating data on the relative abundance of the species, trophic linkages and the physical environment from which the impacts of longline fishing on the ecosystem can be investigated and from which alternative harvest strategies can be evaluated.
