Danielle Edwards: Can we expect our own Great Barrier Reef at the Opera House?
Professor David Booth: That’s interesting, but no, we won’t. We actually have three species of coral that natively occur here and maybe one day we will see a big shift towards a tropical ecosystem, but that’s not going to be for a while yet. Meanwhile we have nearly 600 species of fish and huge biodiversity here despite the edges of the harbour being man-made with seawalls.
DE: So what will the Opera House Reef Project involve?
DB: After initial scoping this year, we’ll install a modular artificial reef made up of nine pods, three each of low, medium and high complexity, each around one metre in depth and width. Over the 18-month period the artificial reef is submerged in the harbour, we’ll record baseline data on fish numbers and diversity and assess its impact on marine life. Our earlier research has shown habitat enhancements such as artificial reefs can help improve biodiversity and provide suitable habitat for native species including leatherjackets, juvenile blue groper and seahorses so we’re hopeful for similar success here.
DE: How does this project with the Opera House build on your work from 2014?
DB: We’ve been interested in how fish interact with artificial habitats for a long time and one of those projects involved looking at pontoons around the harbours of Sydney (that’s Botany Bay), Pittwater, Port Hackney and Sydney Harbour itself. In 2014 we conducted a two-year study looking at small enhancements under those pontoons and found we attracted some fish that would have not otherwise have been there including some commercial species juveniles, and so this naturally leads on from that.
DE: What’s the state of Sydney Harbour at the moment? Is it healthy?
DB: Like any urban harbour with millions of people around it there are some issues but I’m pleased to say Sydney Harbour is one of the finest examples of a working harbour that actually has biodiversity. In spite of pressures with stormwater, sewage run-off, dredging and seawalls it’s doing pretty well at least in the water column. If you dig into the sediment there are some issues there of course, with the past use of heavy metals and dioxins so we have to be very careful to not release those, but as it stands it’s in surprisingly good shape.