Data Collection Form
Click here to download the form used to record GPS and sighting data. Requires Adobe Acrobat Reader.
GPS Setting Protocol
The GPS must be pre set to WGS 84 map datum…in the decimal mode…it is currently in this mode, and we hope to keep it there for the next few months.
Check the read-out; It should look like 151° 17.*** and 33° 48.***
It should read accurate to 3 decimal places. If it does not then undertake the following steps:
Drop the weight into the water as someone hits the "MARK" button on the GPS (whatever datum is set). This saves a 'way point' and shows position.
To save this mark as a way point in the GPS… hit ENTER.
Make sure you record which way-point (if recorded) on the data recording sheet. We can retrieve it later and convert it to WGS 84 if necessary.
(Even if GPS read out IS obviously set to the correct datum, you can still save the way-point in the GPS).
In Water Methodology Used to Locate & Record caulerpa taxifolia
Anywhere at all is of interest, in about 5-10 meters of water.
The rig to conduct the research is permanently on the boat…a yellow weight with "Tony URG" on it, attached to a rope with a dive flag float on the end. The other necessary ingredients are a minimum of 3 divers and a pencil to record the GPS location. The GPS must be pre set to WGS 84 map datum…in the decimal mode…see separate sheet.
What is NOT on the boat is a marked come-home line.
I have marked my come-home reel with a marker pen at 5m intervals; One black mark on the line at 5m and 2 marks at 10m Then, another black mark at 15m and another double one at 20m makes it very easy.
The in water process can be described as follows:
Drop the anchor in 5 to 10 metres of water, and let out a reasonable amount of rope…we have found that in VERY STILL conditions, the reef anchor and chain is enough to hold the boat comfortably…though if it is windy…there is a sand anchor in the forward cabin. Wait till the boat settles down. Have the weight/rope and float ready to drop over the side next to the steering wheel. Remember, the float will not necessarily always be alongside to boat due current/wind.
Drop the weight and IMMEDIATELY record the GPS data. It will be something like
151° 17.??? and 33° 48.???
3 divers enter the water. More are of course possible and welcome! Good buoyancy is vital on the bottom
Diver 1 stays with the yellow weight; He/she is the overall supervisor of the operation.
Diver 2 has the come home line, which is then attached to the D ring on the yellow weight. He/she swims out a distance of 10 metres.
Diver 3 stops at the 5m mark on the line. (Can be more than one diver 3).
Diver 2, when reaching the 10m radius notes a compass heading, and then begins to swim in a circle, by keeping the line taut. Diver 3 follows the line around at the 5m mark. When the compass heading comes around again, it means that the 360° has been done. Diver 1 also monitors this from the weight.
Diver 2 then goes out to the 20m mark on the line, and diver 3 to the 15m mark. Repeat the circle (a little more difficult this time).
All 3 (or more) divers are looking for caulerpa taxifolia of course. It's important that none of the divers following the line around actually hold on to it! Just follow it. You might have to lightly 'lift' the line to clear bottom objects…and the occasional anchor/mooring might pose a challenge to all concerned…but it can be done.
With a few more divers, it is possible to do just a single 20m sweep, making sure that the area of the circle swept is covered visually. In really bad viz, it might only be possible to do one 5m sweep at a time, (requiring 4 circles) but we do need the 20m radius covered on all these dives.
It is of course possible to do an even larger sweep, if numbers and conditions allow.
If Caulerpa taxifolia IS found…please record where; magnetic direction from the centre weight, approximate distance from weight and the depth .
Maps showing Caleurpa taxifolia in North Harbour (click to enlarge).
Background 2003 - 2004
This project was established as part of the North Harbour Aquatic Reserve Biodiversity Study, which the Underwater Research Group has been funded to undertake by the Commonwealth Government's "Envirofund Australia". At a meeting at the URG President's home on January 20th 2003, I volunteered to co-ordinate that part of the project to confirm whether or not Caulerpa taxifolia was present in the North Harbour Aquatic Reserve. It was also decided to include the reaches of Middle Harbour, up as far as the Spit Bridge.
Method
Most dives have been done using a simple circular search pattern with a 10-30 metre radius from a central point. One dive, (No 10) was done inside the pool at Manly Cove using a straight line search pattern. Nicky Cooper sighted Caulerpa taxifolia near Marineland on the Clean-up Australia day, (dive 10a) and Simon Dakin and the author sighted and photographed a small area of Caulerpa taxifolia in Little Manly Cove on June 19th…2 days before dive number 15 in the data sheet. We failed to find this patch on the Caulerpa dive!
Diving
As the accompanying spreadsheet indicates, the URG has undertaken 21 dedicated 'caulerpa dives', that is, dives where the sole purpose was to search for evidence of the weed. All 21 dives have been carefully plotted on to a chart, the first on January 15th 2003 and the last on February 14th 2004. These include 2 days of caulerpa research only dives, which account for 9 of the 21 dives undertaken. Five were done on February 16th, and four more on June 21st,. Another six were done on days when NHAR research dives were convened, one was incorporated into the Clean up Australia Day on March 2nd and five were conducted after regular URG scheduled dives, on the return from outside dives.
In all, 20 URG divers have taken part in the project dives at their own expense (see accompanying chart), and a total of 361 minutes have been spent underwater. The deepest dive in the project has been 19m, but mainly, diving has been above the 10m mark. Three dives (5, 6, 7) were carried out in the Clontarf/Spit Bridge area, three (1,2,19) in the Quarantine/Spring Bay area, eight (8, 9,11, 12,13,14, 20, 21) in the Reef Beach/Forty Baskets area. Three were done in the Manly Cove/Marineland area (4, 10, 10a), four in Little Manly Cove/Collins Beach area ( 3, 15, 16,17) and one (18) at Grotto Point.. My original idea with this project was that dives would be undertaken on the way back in, from scheduled URG dives, but in fact, only 5 such dives took place. This accounts for about 25%, but I had hoped there might have been more.
Results
"The area of interest is all of North Harbour, and Middle Harbour up to Spit Bridge. Of special interest is the Forty Baskets Beach/Reef Beach area of North Harbour." This quote is from the initial notice about the project, and it has proven to be accurate, as it is in the Forty Baskets/Reef Beach area that Caulerpa taxifolia has been found in abundance. Dives 8,12,13, 14 and 21 all provided positive proof that the weed was present. A frond attached to our anchor at the conclusion of dive 14 may indicate just one of the ways that the weed is spread. Following positive identification by fisheries after dive no 8, the patch was visited by them, and treated. We returned to the same site on June 21st, and Feb 15th (2004) and while it was noticed that the area of infestation had spread to become larger on the June dive, it is a moot point whether the area was any worse on dive 21 on Feb 15th 2004.
As far as the initial purpose of the project is concerned, I would have to say that we have been successful. That is, we have proof that Caulerpa taxifolia is present in the North Harbour Aquatic Reserve, and the fact that Caulerpa taxifolia has been found in areas where there is high boating/anchoring traffic, off Reef, Forty Baskets and Quarantine Beaches, would indicate that it is very likely that it will spread. This information has been sent to James Sakker at fisheries, and I am pleased to report that the URG's work complements rather than duplicates that which fisheries are doing.
I am grateful to Tony Wright who set up the weighted rig to do the research, and I would like to thank all the divers who took part, with special thanks to Wayne Hack and Michael Abbott for assisting with the convening of the dedicated research days.
Colin J. Piper
24 February, 2004
Continuing Research...
In late 2007, David Roe, the Harbour Keepers and Coast Keepers coordinator at the National Parks Association of NSW asked the URG to undertake some further investigation into the presence of Caulerpa taxifolia in Sydney Harbour, and, while concentrating in areas outside the North Harbour Aquatic Reserve, to re-visit some of the sites visited in the 2004 survey.
We commenced this new research on Dec 31st 2007, and in 2 months, have conducted 14 dives looking for Caulerpa taxifolia, and while it is far too early to draw any conclusions, it would appear from early results that there is more of the weed present, than there was in 2004. On the 14 dives, we have found Caulerpa taxifolia at 11 sites, 2 of which were also visited in the 2004 project. Most of our activity has centered on the area from Parriwi point, just down-harbour from the Spit Bridge, to Cobbler’s Beach, which is just below HMAS Penguin. Significantly, we find Caulerpa taxifolia in areas where boats anchor for picnics, sheltering from the prevailing nor’easters or southerlies. We do know that Caulerpa taxifoliais easily spread from anchor chains/anchors and this seems to be borne out by what we have found. At some sites, there were a few small isolated plants in an otherwise barren sand bottom (near Quarantine for example) and at others, Caulerpa taxifolia grows among posodonia and Halophila ovalis (off Reef Beach). During Clean-up Australia Day at Balmoral, Caulerpa taxifoliawas recorded inside and outside the pool, as well as among some of the moored boats just off the shore.
The results, of all the research can be viewed by clicking on the link above, and I hope to up-date these findings every couple of months.
Colin J Piper
3 March 2008
Images of research activities
Images of Caulerpa taxifolia, found near Forty Baskets Beach in North Harbour - (click to enlarge)
Contact Details
Please fill in as much information as you can onto the Data recording sheets in this folder. There is also a laminated sheet describing the weed…and a colour photo. My best advice is to be on the lookout for small seaweed which resembles a fern. Please send the results to me as soon as you can, so that I can keep the data up to date. I will need the data sheet you fill in as well.