This flythrough combines bathymetry with high-resolution imagery to highlight canyon environments within the Gascoyne Marine Park located offshore northwestern Australia. The Cape Range Canyon is a relatively narrow, linear canyon that initiates on the continental slope, but is connected to the shelf via a narrow channel. The walls of the canyon are steep and reveal a history of slumping and retrogressive failure, that have broadened the canyon over time. The floor contains a series of deep plunge pools, indicative of the action of sediment-laden turbidity currents in further eroding this canyon. Epibenthos within the canyons was relatively sparse and likely regulated by disturbance associated with sedimentation in the canyons. Rock overhangs often supported the highest densities of benthic suspension feeders, including glass sponges, octocorals and ascidians.

Link to video:    Seafloor Bathymetry of the Gascoyne Marine Park

This is a technical report for the Hunter Marine Park surveys as part of the NESP Marine Biodiversity Hub D3 project. The report summarises five years worth of multibeam echo sounder, towed video, stereo-baited remote underwater video and remotely operated vehicle surveys to provide Parks Australia with baseline information for the Hunter Marine Park. The Hunter Marine Park is located of the mid-NSW coast and continental shelf rocky reef was identified as a key ecological feature of the Park. The MBES surveys mapped 30% of the continental shelf component of the Marine Park and identified approximately 5.5km2 of rocky reef. Towed video surveys found these reefs to covered in a diverse range of sessile invertebrate assemblages. The stereo-BRUV surveys focused on three distinct regions across a depth range of 35-120 m. Up to 112 species of fish were identified, including three threatened and protected species. Each of the three locations were deemed to support a unique species assemblages. However, the patterns in distribution where highly species specific and often related to reef structure and season. These are the first mapping and biological surveys of the Hunter Marine Park region.

In early 2020, a team aboard the RV Falkor explored two deep-sea canyons within the Gascoyne Marine Park. More than 30 new species were discovered, 2570 seafloor images were annotated, and 11,250 km2 were mapped. This survey confirmed that canyons within Gascoyne Marine Park are ecologically important systems, supporting numerous deep-sea species, many of which were discovered to be new to science. The advanced capabilities of the ROV SuBastian to navigate and image complex (near vertical) walls and overhangs within the canyons revealed patterns in the distribution of the seafloor taxa consistent with small-scale environmental variability. Repeat multibeam mapping revealed a dynamic canyon system that continues to be shaped by turbidity currents. The occurrence of reworked seagrass blades within the canyons provided a new understanding of these canyon systems as an active conduit between shallow shelf and abyssal environments. The distribution of the seabed biota revealed through quantitative ROV transects emphasised the importance of disturbance patterns in shaping the canyon ecosystems.

In October 2019, opportunistic mapping and imagery of the Wessel Marine Park on the RV Investigator revealed a localised band of high biodiversity linked to a unique and culturally important geomorphological feature in the otherwise uniform seascape prevalent in the Wessel Marine Park. Our findings help contribute to an understanding of the values of a northern marine park, including an inventory of communities and habitats as well as potential relationships to geomorphic features and culturally important sites. This has national significance to the implementation of the northern marine park management plan, as well as informing future monitoring programs in northern Australia.

EXECUTIVE SUMMARY
This post survey report details the data collected within the Coral Sea Australian Marine Park onboard the RV Investigator (IN2019_V04) between the 7th of August and the 3rd of September 2019 associated with the primary voyage Hotspot dynamics in the Coral Sea- connections between the Australian plate and deep Earth’ (Whittaker 2020). The data and preliminary results in this report pertain to ongoing research to examine spatial patterns in deep-water seafloor biodiversity, in particular, how organisms are related to geomorphic features within the Coral Sea Australian Marine Park (AMP). The seafloor biodiversity and associated geomorphic habitats in this AMP are poorly understood, and given the recent release of the AMP rezoning, it is particularly important to understand the spatial variability of seafloor biodiversity and associated habitats to better quantify the biological assets within the AMP.