URG Bulletin July 2021

President's Slate

- by Duncan Heuer


Well we're back in lockdown but hopefully some of you live within exercising distance from a beach and are still managing to get in the water while remaining safely within the confines of the NSW guidelines.



Personally, we got a dive in at Manly it turned out to be a fantastic day. Charlie, club secretary snapped up this great photograph of a giant cuttlefish with some curious swimmers overhead. We've also been getting into a lot of free diving instead and are pleased to say that have seen grey nurse sharks in Bondi on every occasion - the lowest number on dive being four and the most we saw one morning was nine!



We had our first URG club social event for the year back in June at the Oaks Hotel and it was great to see familiar faces again without wetsuits on for a change. We also had three new members present which was also encouraging.


A reminder from the set of comms that Reef Life Survey (RLS) has also secured a grant to train additional divers. Please register your interest by emailing John T and registering with RLS. If you are already qualified there are plenty of opportunities to dive from the URG boat for free when completing surveys.


Our club trip to Lady Musgrave and surrounding islands/dive sites is still scheduled to go ahead, permitting interstate travel is allowed. Dates for the full trip are 18th to 26th September.


Unfortunately I don't have a lot of other news as activity has come to halt. A big thank you to Michael Abbott, John Turnbull, Sarah Han de Beaux for supplying articles for this issue of the Bulletin. We are always looking for content so please send in an article via email to get published on the website. We are still on the lockout for a volunteer to coordinate collating our monthly Bulletin. If you are interested get in touch.


Hope you enjoy the articles that follow and also hope that we contain this virus so we can get back on the boat and enjoy the stunning conditions on offer this winter.


Duncan Heuer

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Exmouth Navy Pier

- by Michael Abbott



We had the privilege of diving on the Navy Pier when recently in Exmouth. There is only one operator in town licensed to dive the pier that being Dive Ningaloo (DN). They are highly recommended as being very professional, safety conscience and have friendly and helpful staff. A special mention to Chloe and Kristen. Unlike the other operator in town, they did contact us to let us know if the dive that day was cancelled due to weather. Much better than sitting in the rain waiting for a bus from the other operator that never arrived. On this day Dive Ningaloo picked us up from our accommodation and after a short stop at the shop to connect the trailer and check everyone had all gear, we headed on the 20-minute drive through the desert north to the pier.



There is a requirement for a photo ID, usual rules and expected paperwork to enter an active Australian Naval Base. We also had a talk and a video on the way on the history of the base which was started by the USA in WW11 as a submarine communication centre which was very interesting.



The bus and trailer drives to the end of the pier and parks next to the steps leading to the dive platform. Very convenient. On arrival we had a slight problem due to the blood moon due that night in that the tide was still running hard. Think Swansea Bridge tidal run. The Pier is located on the bay side of the Exmouth peninsula, and can only be done at slack tide so visibility is not expected to be fantastic. We had 3 to 4 meters. Finally, the tide slowed, and we walked down the steps to the platform which today was a good 3 meters above the water line. Final safety brief and we stepped out into thin air.



I would rate this shore dive site up there with Swansea Bridge with large columns and cross members supporting the infrastructure above providing shelter for masses of smaller fish which in turn attracts predatory fishes. Maximum depth was 12.2 meters. The difference is the water temperature at 24 degrees and the latitude supports even more tropical species. Benthic life is not prolific in regard to number of species, and the bottom has a fair amount of debris from years of use which supports some benthic and provides hiding spots for small cryptic species.


We spent 48 very enjoyable minutes before the tide turned and caution had us return to the steps at the dive deck. On the dive we saw 2 female grey nurse sharks (1.6 and 1.2 m respectively), lots of groper around the 1-meter mark which seemed to like to sit in the higher corners of the structure where current was less, and bait fish were abundant. There were lots of big emperor (mostly spangled), trevally and giant sweetlips hunting the glass fish and assorted small baitfish.



We also saw a banded wobbegong hiding under the debris and a turtle on the surface. Tropical species included lots of angelfish, a puffer, a few butterflyfish, bannerfish, lionfish, Moorish idols and a parrotfish. Off the pier the water was green. Under the pier the dive was dark and gloomy, so fish did get up close and personal as I feel they saw us about the same time we saw them. The torch came in handy. Much of the dive was spent halfway up the structure enclosed in schools of different baitfish waiting to see what came through for a feed. Overall, a very good dive. If you have done Swansea Bridge you will be familiar with this type of diving.



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From the archives (2007): Protecting marine biodiversity from the Killer Algae

- supplied by Michael Abbott


Sydney Metro 38396


NSW Department of Primary Industries - NSW Government


Caulerpa taxifolia is a fast-growing seaweed, nick-named Killer Algae after escaping from aquariums in Germany, where it had been specially bred to be extremely hardy.


Normally only found in warm tropical waters, the aquarium strain has colonised thousands of hectares in the Mediterranean, from France to Croatia, and is now established in California, where it threatens marine biodiversity like any vigorous weed plant.


A group of Sydney dive enthusiasts were concerned the weed would invade North Harbour Aquatic Reserve in Sydney Harbour, after colonies were discovered in NSW estuaries, most likely from plants escaping from anchor chains of visiting ships or from fishing gear .


The reserve protects sealife such as anemones, worms, sponges, shrimps, crabs and molluscs, and shelters seagrass, seahorses and sea dragons, which would all be threatened by the Killer Algae.


Funding


An Australian Government grant of more than $11,000 assisted the Underwater Research Group to confirm whether or not Caulerpa taxifolia was present in the North Harbour Aquatic Reserve.

This grant was also used to establish a base-line study of the biodiversity within the North Harbour Aquatic reserve. The data the URG recorded can be used in the future to assess the overall state of this waterway.


Activities


Project spokesman Colin Piper, vice-president of the Underwater Research Group, said the group carried out many dives to look for the Killer Algae and found it was present, , but at this stage it appears not to be the Mediterranean strain.


“It is most likely a strain found naturally in Moreton Bay.;


“For the base-line study, we searched along 50 metre transects from a pre-determined GPS position to gather baseline data for the biodiversity survey, and for the Caulerpa research, we used radial searches from a central GPS position.. We have re-visited several of these positions and have noted varying changes in the amount of Caulerpa present.


“We determined that our methodologies worked well and have supplied the data we obtained to the Port Stephens office of NSW Fisheries.” They have visited several of out sites to confirm our findings.


Achievements


“It has been a highly successful project,” Colin said. “Up to that point divers had reported seeing the Killer Algae, but it was only hearsay,” he said.


“Now we have proved that it is established, and our advice is it is probably not a threat to the same extent it is overseas; Fisheries undertook some eradication programmes but I understand it had a limited degree of effectiveness. Like the cane toad, it has probably migrated south from Moreton Bay.


“But the data we have obtained will allow us to keep a watch on it.”


Further reading here on DPI's website


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Finding happiness in Sydney's underwater world

- by Sarah Han de Beaux


I was once listening to people discussing whether their memories of happiness are just an illusion. Were they actually truly happy in the moment, or was it just looking back at that memory over time that makes them happy? For instance, when on holiday we take lots of photos of us smiling and so it gives an illusion that every holiday is happy from start to finish. Whereas, we all know that we have smiled for the camera briefly and then continued doing what we were doing. It isn’t actually a continuously happy occasion from start to finish. However, there is a place I often frequent which does give me true happiness. I appreciate it is not accessible to everyone, but most people who could experience this source of happiness are instead clouded with misconceptions and fear and so they won’t even try it out. I would like to talk about this source of happiness and describe experiences where yes, in that moment I have been truly happy. For me, and my community of friends, the place to go…is underwater! I hope that by sharing my experiences with others it may inspire others to not only explore the underwater world, but to protect it for the future.

Living in the city of Sydney, Australia comes with a major benefit that millions of people living here do not appreciate or understand. Here is where to find the octopus! For years, I had been diving around the world hoping to see an octopus. I have had plenty of dives at the Great Barrier Reef and not seen a single octopus. Over multiple dives at the Galapagos, I did not see a single octopus. Across many other dives in the tropical waters of Philippines, Indonesia, Thailand, and Borneo, I recall seeing just two octopus, but both very briefly as they were super shy and disappeared quickly. Again in the Mediterranean and Atlantic ocean across the Azores, Tenerife, and Croatia, I have not seen a single octopus. Even on other popular diving locations up and down New South Wales, and the rest of Australia including the Ningaloo Reef, I can probably count how many octopus I have seen on one hand. Yet in Sydney it is rare to miss an octopus! They can be seen on almost every dive in Sydney. This is not to say they are overpopulated. And you are certainly not guaranteed to see them! But if you know where to look, you will find them. We have a healthy population that are tame and fairly familiar with divers and so do not always hide and disappear away. Of course, the behaviour they show you will align with the behaviour you show it. If you are fast with your movements and appear to be threatening to the octopus then of course they will disappear and hide, but as long as you are calm, kind and give them space then you can get wonderful experiences with these gentle animals.

Over hundreds of dives in Sydney I have had countless experiences with octopus and I never get tired of them. At one dive site in Sydney’s harbour, I spent almost an hour just hovering over the sandy bottom and watching two octopus interacting with each other. They were mating not body to body, like us humans would, but sat side by side in their separate dens with his long mating arm, known as the hectocotylus, outstretched into her den presumably reaching inside her mantle to pass on his sperm. It was incredible to watch. Even whilst he was busy in this task he was watching around him and using his other arms to continue holding shells against him like a cloak of disguise! The whole experience was fascinating to watch. I later learned that the male does this in case the female decides to reward him by eating him! At least by just stretching out his arm she can bite off his arm and he will survive.

In Kurnell, Botony Bay in Sydney, I once watched two octopus mating in a more familiar fashion, on top of each other. It was like watching a dance – again, simply fascinating. It may not have ended too well for the male octopus though if she decided to eat him afterwards! At night in the harbour, you can get really up close and personal with octopus – they seem far more curious at night and it is an incredible experience to play with them. My favourite experience of interacting with an octopus was again, in Sydney Harbour, this time in the daytime, where there was an octopus who started to interact with me. At first it was so shy as I hovered in the water next to it, but then it extended its arm slowly and touched the edge of my hand. Just as it touched me, it recoiled straight away, but I just stayed still, so it did it again and again. Before too long it had built up the courage to happily extend its arm and place more of its suckers on my fingers, then my hand, and eventually as it built some trust it would start to pull me towards it. Over 30 minutes went by, with this octopus just looking at me and using its arms to work out what I was. I could see that it was learning from the experience too and so this stands out as another awesome experience where I sat with a wild creature and we both shared in the experience of learning about each other.

Considering that octopus are in the mollusc family, and are genetically closer to an oyster than you or I, this incredible short lived animal is very intelligent. When a human baby is a few months old, I think we can all agree they are not capable of that much. Yet a 2-month-old octopus knows how to change its colour and shape of skin to camouflage with its surroundings, almost perfectly I would add, and can work out that I am a completely different animal that is not a threat and it can learn to play and interact with me. Mind blowing right? So next time you are considering to have a life changing experience, just check out what is underwater in Sydney!

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Creature feature: Hawkfishes

- By John Turnbull


Lyretail hawkfish Cyprinocirrhites polyactis - Stradbroke Island


Hawkfishes are a family of largely tropical fish that are associated with corals, and in sub-tropical regions with sponges and rocky outcrops. They are characterised by bright, mottled colouration, hairlike filaments on the tips of their dorsal spines and their habit of perching on coral heads. They can do this without harm (corals can be unpleasant for fish to perch on due to their chemical defenses and sometimes their sting) as hawkfish have no skin on their pectoral spines, so are somewhat immune to these defences.


Paracirrhites arcatus Ring-eyed hawkfish - Stradbroke Island


Like wrasse, many hawfishes are born female, and the dominant fish in an area changes to male. They prey on small fishes and crustaceans when they pass within striking distance. Whilst most hawkfish are benthic (live on the bottom), the lyretail hawkfish is often seen swimming among schools of similar looking fish like basslets, which it resembles in colour and shape. If you’re doing surveys, it pays to look carefully at these brightly coloured schools in case they harbour an interloper (like hula fish and the hit and run blenny!).


Falcon hawkfish - Stradbroke Island


On our recent trip to Stradbroke Island (where the diving was great!!) we recorded five species of hawkfish; freckled, falcon, blotched, ring-eye and lyretail. Anyone who has dived Lord Howe will know the brightly-coloured splendid hawkfish. Australia has several other species, but i don’t have pics of those!