Marine Biodiversity of Southern Sydney Harbour's Journal

We thought we'd do something a little different for the Photo Observation(s) of the Month of December, and include four amazing observations of a particular group of fish. And so congratulations to Erik Schlogl and Nic Katherine for their observations of two Common Stingarees (Trygonoptera testacea) (observation one and observation two) and two Coffin Rays (Hypnos monopterygius) (observation one and observation two) at Parsley Bay.

The reason that these observations are both timely and important is that in December 2023, a research project commenced on characterising the Stingaree and Stingray population at Parsley Bay and Camp Cove in Southern Sydney Harbour led by Nic Katherine. Rays in the order Myliobatiformes (which includes cownose rays, devil rays, eagle rays, manta rays, stingarees, and true stingrays, among others) and Torpediniformes (which includes coffin rays, numbfishes, and torpedo rays) started diversifying in the late cretaceous (~100 million years ago), with the former having 63 species and the latter 7 species known from Australia.

In New Zealand for example, these amazing creatures are believed to be spiritual guardians (or Kaitiaki) protecting the shellfish beds within their harbours and estuaries. In Māori culture, a Stingray barb, deeply thrust in, which cannot be withdrawn, is a metaphor to describe an idea that has taken hold in the mind or a grudge between people that was difficult to overcome. Nicole is excited to learn more about the amazing lives of rays right here in Southern Sydney Harbour.

Nicole's first observation at Parsley Bay as part of her standardised, "timed swim" visual survey approach was a 2 metre Smooth Stingray (Bathytoshia brevicaudata), gliding around and underneath the wharf, eating the bait from the sea floor discarded by fishers on the jetty. The Smooth Stingray is the largest species in the world within the Dasyatidae family of true stingrays. On her first survey at Parsley Bay, Nicole observed one Smooth Stingray, ten Estuary Stingrays (Hemitrygon fluviorum), two Kapala Stingarees (Urolophus kapalensis), one Coffin Ray (Hypnos monopterygius), and three Common Stingarees (Trygonoptera testacea). Not bad for her first time out to survey rays in Parsley Bay!

This self-directed project is supported by Dr Joseph DiBattista, now at Griffith University in the Gold Coast, and complementary data collected by fellow citizen scientists as part of this Marine Biodiversity in Southern Sydney Harbour iNaturalist page. The project aim is to learn more about the diversity and residency of rays in Southern Sydney Harbour. Nicole has been enjoying the experience of immersing herself in the rays world, with some of the juveniles dancing and chasing one another in the shallow waters, whereas others were more cryptic, tucked beneath overhangs or covering themselves with sand. The surveys will continue over the next 4 months.

This journal post was written by project leader and iNaturalist member, Dr Joseph DiBattista, as well as iNaturalist member, Nic Katherine.

I am here asking for everyone's help with the habitat restoration component of the Blue World funded Valerie Taylor Prize project on "Marine Biodiversity of Southern Sydney Harbour". Our seahorse hotels have now been deployed for just over 10 months in Parsley Bay but we have not had the opportunity to dive and photograph them for at least 4 months. The four seahorse hotels were installed by Sealife Aquarium on March 23rd, 2023 in approximately 6 metres of water about 10-15 metres north of the swimming net, which is in the process of being replaced with a new one. The approximate location of the four seahorse hotels is flagged in the Google Earth image displayed above. Time permitting, I encourage everyone (anyone!) to get in for a dive in the month of February and report back with photographic evidence demonstrating that these structures remain in place after the new swimming net construction (which began January 22nd, 2024 and included the anchoring of barges to import construction materials), the state of marine growth and accretion on the seahorse hotels themselves, and whether any White's Seahorses are using this habitat as their new home.

This journal post was written by project leader and iNaturalist member, joseph_dibattista Dr Joseph DiBattista.