Poster Presentation Australian Marine Sciences Association 2026 Conference

Revealing the role of the swash zone in larval and juvenile fish settlement within urbanised estuarine seascapes (139542)

Jessica JN Nguyen 1 , Clare CJ Jackson 1 , Nathan Knott 2 , Matt Taylor 3 , Daniel Hewitt 1 , Will Figueira 4 , Iain Suthers 1 , Matt Rees 2
  1. University of New South Wales, Kensington, NSW, Australia
  2. Fisheries, NSW DPIRD Fisheries , Husskison , NSW, Australia
  3. Fisheries, NSW DPIRD Fisheries , Port Stephens , NSW, Australia
  4. School of Life and Environmental Sciences, William Figueira, Sydney, NSW, Australia

The swash zone is a ubiquitous habitat across estuarine seascapes, linking habitats between shallow patches of vegetation or intertidal hard structures. However, the role of this habitat in the early life history of fishes has not yet been considered. We assessed the swash zone as a settlement habitat relative to seagrass and examined how proximity to hard structures influenced post-settlement larval and juvenile fish abundance and diversity. Sampling occurred in Gamay (Botany Bay, Sydney),a highly modified estuary, and Jervis Bay, a relatively undeveloped estuary. Post-larval fish were sampled using a fine-mesh beach seine in the intertidal swash zone of estuarine beaches. We found high abundances of larval and juvenile fish within the turbulent swash zone including several commercially important species, whilst seagrass habitats had larger and more predatory fish. Whilst close proximity to structures showed increased fish abundances. Together, this shows the importance of understanding overlooked habitats like the swash zone for spatial management to better support connectivity, biodiversity, and fisheries in estuarine ecosystems.