Finding inshore fish nurseries

Inshore nursery habitats are vital for many fish species. The rich abundance of fish using these nurseries is valuable for recreational, commercial, and cultural purposes.

Despite their importance, these nurseries are often overlooked. Data on fish communities, especially juveniles, in habitats like seagrass and mangroves are scarce.

Identifying fish nurseries ensures appropriate management to support adult populations. Understanding fish size, distribution, and habitat connectivity is essential for effective species management.

TropWATER scientists, in partnership with Traditional Owners and Rangers, are addressing this gap in the central Great Barrier Reef by monitoring a wide range of inshore fish habitats to collect key baseline data.

Surveying fish nursery habitats

Our team are conducting fish surveys of inshore habitats between Dunk Island and Magnetic Island over two years. We are monitoring nursery seascapes of habitats of a variety habitats – from mangrove, seagrass, shoals, algae, and reef habitats using underwater stereo camera systems.

The project is a collaboration with Traditional Owners and Rangers from Girringun Aboriginal Corporation, Minga Minga Rangers, and Wulgurukaba Rangers. They contributed to the survey design, using local and cultural knowledge for site selection, and participated throughout the field surveys.

Monitoring surveys for inshore nurseries incorporate the following:

• Surveys in three seascapes: coastal, inter-reef, and islands.

• A variety of habitats, such as mangroves, seagrass, shoals, algae, the bottom of reef slopes, and reef flats.

• Use of stereo non-baited Remote Underwater Video Stations as well as Baited Remote Underwater Video Stations for fishes and drop cameras for benthic habitats.

• Two surveys conducted per year, for two years.

These surveys will increase our understanding of the role that habitat plays in fish abundance and size. They will also be integrated with inshore fringing reef and deep-water inter-reef monitoring undertaken by the Australian Institute of Marine Science, the University of the Sunshine Coast, and other TropWATER researchers to deliver a more comprehensive look at reef fish status and trends.

Creating a monitoring baseline

This project will develop a baseline of monitoring data for inshore fish habitats. Future assessments of the status and trends in fish communities, including how they respond to environmental changes, can then be compared to this baseline.

So far, over 221 fish species have been identified as part of this project. These include many species of commercial, recreational, and cultural importance such as:

• Barramundi (Lates calcarifer)

• Coral trout (Plectropomus maculatus)

• Great hammerhead shark (Sphyrna mokarran)

• Mackerel (Scomberomorus sp.)

Results also showed distinct fish communities in inshore habitats, with certain species associated with particular habitat types. These findings are critical for conserving these habitats to maintain adult populations into the future.

This research supports healthy fish populations and sustainable fisheries. It informs strategies to protect critical habitats, supports the replenishment of adult populations, and guides efforts to maintain biodiversity and ecosystem health.

Project details

This project is supported by the Great Barrier Reef Foundation and is a collaboration with the University of the Sunshine Coast, the Australian Institute of Marine Science, Girringun Aboriginal Corporation, Minga Minga Rangers, and Wulgurukaba Rangers.