Assessing fine-scale variability in habitat and fish assemblages on mesophotic pinnacle reefs

Supervisory Team:

Dr Joel Williams (IMAS)

Dr Tim Ingleton (NSW Department of Planning and Environment)

Dr Jac Monk (IMAS)

Brief project description:

Temperate mesophotic reefs are characterised as a low light environment that is beyond recreational diving depths but isn’t considered deep sea. They are poorly understood and difficult to sample ecosystems. Off the Australian east coast there are many small, high relief, isolated patches of reef that extend from the surface to depths below 60m. It is unclear how the algal and sessile invertebrate assemblage changes as rocky reefs descend from the shallows through the upper mesophotic layer and into the lower mesophotic zone. These offshore reefs likely provided important habitat for maintaining biodiversity and supporting fisheries and threatened species. This project seeks to understand how these reefs function within the seascape. How are they connected to coastal reefs. Do they provide stepping stones for migratory species or range shifting species.

In recent years researchers, with the support of IMOS, NSW Government, and NESP Marine Biodiversity Hub have used multibeam echo sounder (MBES), baited remote underwater video (BRUV) and autonomous underwater vehicle (AUV) to collect data on reef structure, habitat, and fish assemblages from these offshore pinnacle reefs. This project will use existing underwater imagery and mapping data to explore variability in habitat and fish across a depth gradient and among reefs. This project will include annotating AUV and BRUV imagery and video and using modelling methods such as GLM/GAM and species distribution models to investigate the association between reef structure, habitat and fish. If the opportunity arises and funding allows there will be opportunities to collect additional imagery

Skills students will develop during this research project:

Biodiversity mapping, image annotation, species identification, study design, species distribution modelling, mapping, possibly include fieldwork to collect multibeam mapping data or towed video.

Authorised by the Executive Director, Institute for Marine and Antarctic Studies
November 24, 2022