South-west Corner Marine Park Survey

PROJECT 1.4

Final report, December 2022

The South-west Corner Marine Park has a rich marine biodiversity with high levels of endemism that supports a range of socio-economic values including important recreation and commercial fisheries. Partnership with Wadandi Traditional Owners and Custodians for this region provided guidance through cultural maps and knowledge to inform the discovery of remarkable biodiversity across submerged ancient coastline features that document the dynamic history of the region.

This survey of the ‘Capes region’ of the South-west Corner Marine Park revealed one of the best-preserved examples of submerged ancient coastlines and lowlands currently observed across the Australian Marine Park network. We found 80% more mesophotic and rariphotic rocky reef habitats within the National Park Zone than expected based on a previous national reef model, with extensive kelp, seagrass and sponge gardens out to the last interglacial paleo shoreline in ~120 m. This survey found the deepest seagrass and kelp recorded in the South-west Network. The survey only reached the shelf break, but here in 220-250 m we found aggregations of Hapuku (Polyprion oxygeneios), a deep-water grouper highly valued by commercial and recreational fishers. We recommend the creation of national benchmarks to enable meaningful comparison of the status and trend of natural values.

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