Oral Presentation Australian Society for Fish Biology Conference 2025

Connecting nursery function, biodiversity values and conservation outcomes across coastal seascapes (124953)

Andrew Olds 1 , Jesse Mosman 1 , Hayden Borland 1 , Ashley Rummell 1 , Sam Allan 2 , Alec Bannam 1 , Stacy Bierwagen 3 , Michael Bradley 4 , Alex Carter 2 , Daniela Ceccarelli 3 , Rob Coles 2 , Mike Emslie 3 , Ben Gilby 1 , Lucy Goodridge Gaines 1 , Edward Hay 1 , Katrina Kaposi 2 , Dmitry Konovalov 4 , Theo Murphy 2 , Jordan Murray 1 , Marcus Sheaves 4 , Timothy Smith 2 , Marcus Stowar 3 , Christopher Henderson 1
  1. University of the Sunshine Coast, Sunshine Coast, Queensland, Australia
  2. James Cook University, Cairns, Queensland, Australia
  3. Australian Institute of Marine Science, Townsville, Queensland, Australia
  4. James Cook University, Townsville, Queensland, Australia

Background

The juveniles of many reef and offshore fish species use a diversity of inshore ecosystems as nurseries, but despite decades of research on nursery function many of these habitats and their interconnections are overlooked in coastal conservation and fisheries management. This is because the fish and functions of coastal habitats are largely studied in isolation, or in some cases are rarely considered at all, and there are little data that can be used to identify and describe key habitats and seascape linkages at scales that are relevant to management. We addressed these shortcomings by surveying juvenile fishes in the full diversity of inshore habitats on the Great Barrier Reef, and by testing which features of local habitats and seascapes were linked to changes in biodiversity and the conservation benefits of local reserves.

Methods

Fish were surveyed from six habitat types (i.e. coastal mangrove, island mangrove, inter-reef seagrass, mixed back-reef communities, fringing reef and isolated reef) using stereo-remote underwater video stations. Surveys were conducted four times over two years and included 3,600 deployments along 200 km of the inshore Great Barrier Reef, Australia.

Results

There were clear differences in the biodiversity and fisheries values of focal habitats, which were typically highest for deeper shoals and back-reef environments that are rarely monitored or considered as priorities for management. The biodiversity and fisheries values of all focal habitats were also strongly linked to variation in their spatial context, and to a lesser degree to changes in habitat condition or composition. Distinct seascape features were, however, important to assemblages in different habitats, and these had significant effects on the performance of local marine reserves.

Conclusion

Our findings illustrate the importance of seascape connectivity and diversity for nursery function, biodiversity and conservation, and we suggest that a deeper understanding of patterns of seascape use is needed to support coastal management decisions for fish and fish habitats.