Shiprock 12 Hour Environmental Survey 2017

Repeating a Milestone in Marine Research after 50 years

Shiprock is a small Aquatic Reserve sanctuary zone in Port Hacking, Sydney, renowned for the high diversity and abundance of its marine life. In the early days of discovery of Shiprock, in the 1960s, URG systematically recorded the benthic and free-swimming marine life at Shiprock. This included two detailed transect surveys perpendicular to shore and hundreds of hours of diving over a five year period. In November 1966 URG conducted a 12 hour survey of Shiprock, focusing on currents, temperatures and other environmental factors.

On 12th November 2017, URG returned to Shiprock to repeat the environmental study.

Social

We had a great turnout, with many members comparing notes and sharing stories. Social researcher from UNSW, Yolana Kajlich, interviewed several URG members.

Divers entered the water in the morning before low tide, then surveyed on the hour until the late afternoon:

TIMEDIVERSSHORE SUPPORTCOMMENTS
8amPablo Bolomey, David MassihJohn TurnbullGetting the gear set up first!
9amKathy Giles, David MassihJohn Turnbull
10amJohn Turnbull, Kathy GilesPablo BolomeyLow tide
11amJohn Turnbull, Pablo BolomeyDavid Massih
MiddayDavid Faulks, Eric FuentesPablo Bolomey
1pmDavid Faulks, Eric FuentesPablo Bolomey
2pmMartin Puchert, Lou de BeuzevillePablo Bolomey
3pmMartin Puchert, Lou de BeuzevillePablo Bolomey
4pmMartin Puchert, Lou de Beuzeville, Duncan GrahamPablo BolomeyHigh tide, biodiversity survey
5pmPablo BolomeyCharlie Elliot
6pmCharlie Elliot, Duncan GrahamPablo Bolomey

Environmental survey

A range of environmental measurements were taken:

TIMETEMPCURRENTSALINITYpHORPDOVIZSG
8am20.37out36.267.163817.445.21.0256
9am20.4out36.257.173757.6871.0256
10am (L)20.48slack36.277.153737.5351.0256
11am20.53in36.277.123727.5651.0256
Midday20.76in (0.6)36.277.093647.564.61.0255
1pm21.08in (1)36.277.033617.594.41.0254
2pm20.09in (0.8)36.397.833637.834.81.0256
3pm20.09in36.397.893668.075.51.0256
4pm (H)20.91slack36.397.93668.1771.0256
5pm21out36.417.913678.076.21.0256
6pm21.04out36.47.923698.0841.0256

Interpretation

  • Temp – water temperature in degrees Celsius.
  • Current – outgoing or incoming, with measurable speed in knots (slight current was not able to be detected by the instrument we were using)
  • Salinity – in parts per thousand (grams of salt per litre). Seawater is around 35.
  • pH – a measure of water quality – pH greater than 7 is alkaline. Seawater pH is around 8.1
  • ORP (REDOX) – a measure of water quality, mV – clean oxygenated water reads up to 400. ORP below 200 is low in oxygen.
  • DO – dissolved oxygen saturation mg/l – 4 and above is safe (ie not hypoxic)
  • Viz – visibility, m – measured by two divers using Secchi disk
  • SG – specific gravity – pure water is 1.0

Biodiversity Surveys:

Biodiversity surveys were also conducted, in line with the year-long effort to do monthly surveys:

Transect A runs from the intertidal zone down to the Pinnacle at 16 m.

Transect B runs from the intertidal zone, slightly further upstream, down to the base of the wall at 12 m.

Species identified in the two biodiversity surveys to date are:

Method 1 (Free swimming fish)Method 2 (Cryptic fish and mobile macroinvertebrates)
Black-spotted goatfish
Blue-lined goatfish
Crested morwong
Eastern blue groper
Eastern hulafish
Eastern talma
Estuary catfish
Fan-belly leatherjacket
Gunthers wrasse
Half-banded seaperch
Hit and run blenny
Immaculate damsel
Luderick
Moon wrasse
Old wife
Pied cormorant
Red morwong
Sawtail surgeonfish
Silver sweep
Silver trevally
Siz-spine leatherjacket
Snapper
Stripey
Sydney cardinalfish
White-ear
Yellow fin bream
Yellow-back puller
Yellow-finned leatherjacket
Yellow-tail scad
Black tip bullseye
Black-throat triplefin
Comb star
Common threefin
Eastern fortescue
Eastern Frogfish
Eastern Red Scorpionfish
Eastern slate-pencil urchin
Gloomy octopus
Half-banded seaperch
Hawkfish
Hoeses sand goby
Indian sea urchin
Murex shell
Sand sifting star
Sweet ceratosoma
Sydney cardinalfish
Triton shell

Thanks

A big thanks goes to Pablo Bolomey for organisting the day, Marine Pollution Research Pty Ltd for providing the measuring gear, and all the divers and shore support who contributed their time.

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