white yellow and black butterfly fish swim over a coral reef


Monitoring reef fish populations on the east and west coast

Monitoring reef fish supports reef management and helps AIMS scientists understand the influences of ocean currents, natural and anthropogenic disturbances, and climate change on reef fish populations and their ecology.

AIMS can compare fish diversity and abundance right across tropical Australia, thanks to the combination of our east coast surveys and our comprehensive assessment of coastal, nearshore, oceanic atolls and shoals from Ningaloo to Darwin.

Deep-water habitats are increasingly targeted for fishing as new technologies make them more accessible. AIMS uses baited remote underwater video stations (BRUVS) to monitor these deeper water fish communities These systems provide new insights into preferred habitats and common movements patterns of fish, which help managers identify areas that need protection.

Monitoring fish communities on the Great Barrier Reef

On the east coast, the AIMS Long-term Monitoring Program (LTMP) has been monitoring fish populations on the Great Barrier Reef for over three decades, using underwater visual survey techniques by expert scientists.

The work has revealed distinct inshore, mid-reef and outer shelf communities on the Reef. These communities also vary with latitude to some degree, with distinctive species in the far north (off Cape York) and south (in the Capricorn-Bunker reef system).

Fish communities on each reef change little over time unless a major disturbance, such as a cyclone, an outbreak of crown-of-thorns starfish or major coral bleaching, causes changes in the seabed community. When the reef is damaged fish numbers tend to decrease, but we have also documented rapid recovery during stable periods.

Our early survey work identified key regions of biodiversity, providing advice for the Great Barrier Reef Marine Park Authority's Representative Areas Program and the subsequent re-zoning of the Great Barrier Reef Marine Park in 2004.

The Long-term Monitoring Program also monitors the effects of zoning on target fish species, such as coral trout, and biodiversity in general. Findings suggest that coral trout are bigger and more numerous in protected areas than in reefs that are open to fishing.

Our current knowledge about fish populations on the Great Barrier Reef is specific to shallow reef areas. Information about fish in other reef habitats and in deeper waters is important for management and fisheries. 

To address the knowledge gaps in these under-surveyed areas, a new two year Integrated Monitoring and Reporting (IMR) Program is observing:

  • juvenile fishes in nursery areas close to shore,
  • fish on fringing reefs surrounding islands close to the coast,
  • and species that live in deeper waters between reefs. 

The Program is being co-developed with Traditional Owners. Hands on training is being provided to Sea Rangers to empower them to conduct their own monitoring in future. The knowledge from Traditional Owners is helping scientists to choose sites for monitoring.

WARNING: Aboriginal and Torres Strait Islander viewers are warned that the following program contains images and voices of deceased persons.

The monitoring of fish in reefs surrounding inshore islands will re-instate 15 years of research in the Whitsundays, the Palm and Keppel Islands, and Magnetic Island, whilst expanding to include four more island groups (the Turtle Group, Frankland and Family Islands, and the cluster of islands off Mackay). 

Technology, such as BRUVS and remotely operated vehicles (ROVs) will be used to observe and record fish in deep water areas between reefs that are beyond the depths of scientific scuba diving, and in shallow areas that we know little about.

The IMR Reef Fish Monitoring Program is funded by the partnership between the Australian Government's Reef Trust with the Great Barrier Reef Foundation. This is a joint program with support from AIMS, TropWATER, James Cook university, M-data Tech, University of the Sunshine Coast, Great Barrier Reef Marine Park Authority and Department of Agriculture and Fisheries (Queensland), and Traditional Owners from Girringun, Manbarra and Wulgurukaba.

Fish monitoring in Western Australia

In Western Australia, our team has been monitoring fish communities over the past two decades in collaboration with various industry, university and state government institutions.

Underwater visual surveys have shown distinct fish communities at remote oceanic atolls and isolated coastal reef environments, with limited genetic mixing between reef systems. They have also found that these fish communities react strongly to natural disturbances such as cyclones and coral bleaching, with key groups declining rapidly with declines in coral cover.

The Western Australian team has also combined resources and expertise with east coast team members to cover marine environments in difficult-to-access and deeper sites using BRUVS to complement visual surveys.