Project Leader: Peter Doherty

Fisheries throughout the world have become over-exploited, yet they can be made economically and ecologically sustainable if based on a sound knowledge of how stocks are replenished.

Fish research at AIMS has progressed from mapping diversity and habitats within the Great Barrier Reef to studying the response of fish populations to fishing pressure. Selected sites have been monitored for almost 20 years to learn how fish populations change over decadal time scales in response to natural disturbances like cyclones, crown-of-thorns starfish outbreaks, and natural variations in replenishment. These observations have resulted in recruitment being identified as a key process, which in turn has led to a focus on the ecology of the pelagic larvae. The Great Barrier Reef and north Western Australia has been extensively sampled over the last seven years to locate preferred nurseries of selected species and to determine travel between spawning ‘sources’ and recruitment ‘sinks’. This work is currently being assimilated into models of water circulation to predict these larval source-sink connections.

The development of robust models of larval connectivity will clearly benefit the management and conservation of fish resources within ecologically sensitive areas, including the Great Barrier Reef. Ultimately, their most beneficial application may be in the design of networks of marine protected areas to sustain fish production in the small fisheries of subsistence economies, where traditional controls are unaffordable. This approach will be pursued through training and partnership projects with scientists from developing nations in the Asia-Pacific region.

In a new initiative for this triennium, scientists from several disciplines are collaborating on an intensive study of the structure and function of pelagic food chains in tropical coastal waters. This work will have immediate relevance to the seasonal use of the Ningaloo Reef by whale sharks and other large plankton feeders, which support a growing ecotourism industry. In the longer term, it will document the nature of seasonal production pulses and their effect on food chain dynamics, and thus replenishment of fish stocks in different geographic regions.

Goals

• to provide information relevant to the conservation and management of tropical fish stocks;
• to understand the responses of fish populations to natural and anthropogenic pressures;
• to predict the effects of fishing on fish stocks, and to provide quality advice to the full range of potential users.

Connectivity of the Great Barrier Reef ( Leader: John Carleton)

Models of propagule dispersal will be used to link source and sink reefs in the central section of the Great Barrier Reef Marine Park, allowing optimum zoning of reefs by the Great Barrier Reef Marine Park Authority.

Population dynamics of tropical fish populations (Leader: David Williams)

Connectedness of populations over greater scales of space and time are being examined to link historical data sets on migratory fish stocks with data on oceanographic variability, to hindcast patterns of gene flow and past colonisation from existing data sets on the biogeographic distributions of reef fishes, and to examine links between habitat quality and the productivity of inshore fisheries.

Replenishment of fish populations in Western Australia (Leader: Mark Meekan)

Fish larvae have been sampled from numerous sites near Exmouth Gulf and Dampier Archipelago. These samples are being analysed to determine seasonal cycles in the Western Australian fauna, nursery habitats for exploited species, and the dependence of Ningaloo Reef on propagules from upstream sources.

Primary production and pelagic food chains (Leader: Miles Furnas)

Patterns of primary production were monitored simultaneously with the fish sampling in Western Australia to follow the linkages between climate, primary production and successful reproduction in coastal fish populations.

Secondary production and larval fishes (Leader: David McKinnon)

The availability of planktonic foods were monitored simultaneously with the fish sampling in Western Australia to determine the effect of food quantity and quality on the growth and survival of larval fishes, which ultimately determines the replenishment of fish stocks. New work has started on the mariculture of copepods to supply live foods for finfish aquaculture.

Sustaining tropical fisheries (Leader: Peter Doherty)

This sub-project includes tasks supported by external funds. In 1999-2000, these include: 1. Capture and culture of postlarval reef fish (Solomon Islands), 2. Effects of line-fishing on the Great Barrier Reef, 3. Dynamics of megabethos on the inter-reef seabed of the Great Barrier Reef Marine Park.

Human Impacts on Coastal Marine Ecology

• data assimilation of larval fish catches into hydrodynamic models.

Monitoring Change in Tropical Marine Biota

• visual surveys of effects of fishing on the Great Barrier Reef.

Predicting the Coastal Marine Environment

• hydrodynamic model of circulation for North West Cape (WA);
• ground-truthing of satellite images of ocean colour (chlorophylls).

Links with other organisations

University of Technology, Sydney, Sydney University, University of Western Australia, Australian Museum, West Australian Fisheries, New South Wales Fisheries Research Institute, CSIRO Marine, Queensland Department of Primary Industries, James Cook University, Australian National Antarctic Research Expedition (ANARE), as well as 13 overseas universities and research organisations from within Indonesia, Papua New Guinea, Philippines, Panama, Solomon Islands, United States and Canada.

Links with strategic directions

1998/99 funding base
Total budget $1,658,000 (80% appropriation; 20% external)

Major external sources:
Australian Centre for International Agricultural Research (ACIAR)
Woodside Offshore Petroleum Pty Ltd
CRC for the Great Barrier Reef World Heritage Area
Fisheries Research and Development Corporation (FRDC)

Scientific staff

Research scientists: Peter Doherty (25%), Miles Furnas (50%), David McKinnon (50%), Mark Meekan, David Williams (50%).

Scientific support: Vicki Bates, Mike Cappo, John Carleton (50%), Samantha Duggan, Andrew Halford, Alan Mitchell (50%), Peter Speare.

Postdoctoral: Laurent Vigliola.

Postgraduates: Anja Hansen, Iris Hendricks, Jennifer McIlwain, Anja Retzel, Melita Samoilys, David Wilson, Steve Wilson.