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.
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:
|8am||Pablo Bolomey, David Massih||John Turnbull||Getting the gear set up first!|
|9am||Kathy Giles, David Massih||John Turnbull|
|10am||John Turnbull, Kathy Giles||Pablo Bolomey||Low tide|
|11am||John Turnbull, Pablo Bolomey||David Massih|
|Midday||David Faulks, Eric Fuentes||Pablo Bolomey|
|1pm||David Faulks, Eric Fuentes||Pablo Bolomey|
|2pm||Martin Puchert, Lou de Beuzeville||Pablo Bolomey|
|3pm||Martin Puchert, Lou de Beuzeville||Pablo Bolomey|
|4pm||Martin Puchert, Lou de Beuzeville, Duncan Graham||Pablo Bolomey||High tide, biodiversity survey|
|5pm||Pablo Bolomey||Charlie Elliot|
|6pm||Charlie Elliot, Duncan Graham||Pablo Bolomey|
A range of environmental measurements were taken:
- 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 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)|
Eastern blue groper
Hit and run blenny
Yellow fin bream
|Black tip bullseye
Eastern Red Scorpionfish
Eastern slate-pencil urchin
Hoeses sand goby
Indian sea urchin
Sand sifting star
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.