Photos | Study reveals Botany Bay's rich but largely unknown marine life

A new study reveals the rich but largely unknown marine life that lies beneath the surface of Botany Bay.

John Turnbull, a scuba diver who knows the bay well, wrote about and photographed the hidden treasure for his PhD in community perspectives on marine conservation.

They include weedy seadragons, red-toed or Bare Island anglerfish, Sydney pygmy pipehorses, blue devil fish, pink soft coral and several species of hard coral.

"Botany Bay is well known for its historic and terrestrial values," Mr Turnbull wrote.

"Perhaps less well known, but equally important, are its marine natural values."

Mt Turnbull said Towra Point provided important habitat for many marine species, but his study focused on areas just inside the bay "where some of the most surprising animals can be found".

"Both La Perouse and Kurnell, are home to a wide diversity of marine life," he wrote.

"Many are endemic to Australia, such as wobbegongs, leatherjackets, sponges and seaweeds.

"Threatened and rare species can also be found here, some of which live in this region and nowhere else in the world."

Mr Turbull said Botany Bay was popular with many users, including swimmers, divers, snorkelers, fishers, walkers and paddlers.

"Despite being of immense natural and social value, the unique marine life at the entrance to Botany Bay has no local geographic protection," he said.

"With good management, including well-placed sanctuary zones, we can preserve this diverse marine community for generations to come."

Gary Schoer, secretary of Southern Sydney Branch of National Parks Association of NSW (NPA) , said the paper was timely coming soon after death of Bernie Clarke, who did so much for Botany Bay conservation.

"NPA has urged the NSW Government to extend marine protections via some well-considered sanctuaries and a modest extension to Towra Point waterways conservation to better protect the Botany Bay values that Bernie Clarke was so passionate about," Mr Schoer said.

"Regrettably, the government had a knee jerk reaction to some limited opposition and decided not to consider any more marine sanctuaries for Greater Sydney's waters.

"NPA urges the community to continue to listen to the more objective scientific arguments that would, if applied to Botany Bay's waters and beyond, do much to ensure that the environment and fishers have fish and other important marine creatures for the future."

Mr Schoer said the association was engaging with local state election candidates across the political spectrum, "urging them to stand up for our rich local marine environment as illustrated in the wonderful images captured by John Turnbull".

Mr Turnbull's paper describes the bay's marine life:

  • Weedy seadragons are endemic to southern Australia. The Botany Bay population, which lives on both north and south heads of the bay, is at the northern-most extent of their range, and is the biggest population that we know of in Sydney. Scientists are concerned that this population may be in decline, and together with citizen scientists they are monitoring it closely.
  • The red-toed, or Bare Island anglerfish, was only described in 2014. It is only known to live in in this area and south to Jervis Bay, and the best information we have on this species is from Botany Bay. We don’t know its status though; whether it’s in trouble or not.
  • Sydney pygmy pipehorses have a similar story - local yet little-known. They are only the size of the tip of your pinkie, so can be very hard to find even when they’re right under your nose.
  • Blue devil fish are a protected species which is threatened by aquarium collection, as it is a large colourful species. It’s a favourite fish for SCUBA divers to see, as it hides under ledges and in the back of caves.
  • The pink soft coral, Dendronephthya australis, is only known from this region and is in the process of being listed as threatened. It suffers from poor water quality, anchor damage and entanglement. The biggest population we know of in Sydney is just inside the entrance to Botany Bay.
  • Botany Bay has several species of hard coral too, like this Coscinaria mcneilli at Bare Island. Members of the Underwater Research Group, who found it in the 1960s and have been monitoring it since, estimate it to be over 300 years old.