Recent multibeam and towed video surveys at Port Stephens have disclosed additional information on habitat extent and diversity on Australia’s temperate southeast coast. Multibeam identified previously undescribed soft-sediment features at Seal Rocks and Broughton Island while also confirming broader geomorphological characteristics including the presence of a shelf sand body. While soft unconsolidated sediments dominate the seabed, reef, and mixed habitats covered 20%–40% of the seafloor over the inner- and mid-shelf and supported morphologically diverse sponge communities. Kelp, urchins, branching algae, and encrusting sponges were common to shallow sites (20–40 m) where depth variability was greatest. Sponges dominated over mid to deep-reef and mixed substrate areas and coexisted with ascidians (50–70 m) or sea whips and gorgonians (80–100 m). Multibeam was effective for identifying reef (82%) and soft-sediment (71%) areas but relatively less accurate at identifying mixed seabed. Further subdivisions within the current classification scheme are warranted if a more detailed and park-specific scheme is required.

Depth range
20- 100 m

Mesophotic “mentions”
4 x (total of 4877 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'temperate mesophotic ecosystem'

Fields
Community structure
Biodiversity

Focusgroups
Overall benthic (groups)

Locations
Australia - Southeastern Australia

Platforms
Drop / Towed Video
Sonar / Multibeam