Saturday, November 28, 2009

Sydney snorkel - Little Bay

19 October 2009

After the not-so-satisfying snorkeling experience at Bare Island in the morning, I went snorkeling at Little Bay in the afternoon and had a fantastic time!

Little Bay
is like an underwater playground for snorkelers I think. It is not a big bay but I certainly saw more interesting creatures in this protected bay. The visibility wasn't uniformly good throughout the bay. I am not sure if it's due to the construction work going on near the beach. Some parts of the bay had great visibility, but not in others. Overall, it's protected and calm.

1. After I hit the water, I first noticed many resident Black Urchins on the reef.

An underwater apartment block occupied by sea urchins

A dense neighborhood

Black Urchin, or Spiny Sea Urchin (Centrostephanus rodgersii)
A close-up photo of this species which I took at the Shelly Beach headland is HERE. I sent the photo to the Australian Museum for identification and received this response from them:

"Our naturalist Martyn Robinson has identified your photo as a Spiny Sea Urchin also known as a Black Urchin, Centrostephanus rodgersii a very common species found in the temperate waters of south eastern Australia. These urchins are extremely active at night and reefs can turn into a black swarming mass at night when as they move around looking for food."

This species is found off New South Wales to Tasmania, but not in Western Australia.

2. I also saw some Eastern Slate-pencil Urchins.

Eastern Slate-pencil Urchin (Phyllacanthus parvispinus)
The slate-pencil urchin uses its blunt primary spines (the big spines on the animal) to wedge itself securely into crevices during the day. It feeds at night by scraping encrusting plants and animals from the reef surface for food.

At Little Bay, however, I saw quite a number of these sea urchins that were just sitting on rock surfaces instead of sitting in crevices. No idea what to make of it. I can't imagine why anyone would remove those sea urchins from their resting spots and place them on rocks. And if that did happen, it must have been recent or the animals would have made their way back to rock crevices for shelter. Perhaps they were dead and hence no longer mobile? Or they also move around during the day?

This species lives off the east coast of Australia (Queensland to Tasmania) but not in Western Australia.

3. I found this Purple-spined Sea Urchin attached to the underside of a huge algae-covered rock.

Purple-spined Sea Urchin (Holopneustes purpurascens)
This sea urchin species is confined to the sheltered and moderately exposed reefs between Richmond River and Ulladulla of New South Wales. So it is not a Western Australia resident. It has a brown or pale pink test (shell), pink spines, and yellow suckers at the tips of its colorless tube feet.

This is a short-spined sea urchin. Its primary spines are up to 4 mm in length, which is really short when compared to the primary spines of the eastern slate-pencil urchin which can be up to 70 mm in length.

4. And I found baked beans underwater!

Swimming Anemone (Phlyctenanthus tuberculosa)
The numerous vesicles covering the column (body) of the anemone make it look like a bag of baked beans. In the second photo, tips of some of the retracted tentacles are visible. The animal attaches itself to the surface of kelps or seagrass during the day. Come nightfall, the animal becomes mobile and feeds by catching drifting food particles with its tentacles.

The first Swimming Anemone is quite large, at least 10 cm in length. The second one, which looks more like baked beans because of its orange vesicles, is smaller, probably about 6 cm long. More photos of the Swimming Anemone that I took in Sydney HERE and HERE.

Southern anemone (Phlyctenanthus australis)
I found this sea anemone on a boulder just a few feet below the surface. It immediately caught my eye when I swam past. It is about 8-10 cm in diameter.

This species is similar to the Swimming Anemone in that they both have numerous bubble-like vesicles on their bodies (columns). The Southern Anemone has grayish blue vesicles and up to 100 red tentacles. Also, unlike the Swimming Anemone, this species remains permanently attached to the reef surface and hence not as mobile.

This species occurs only off the east coast of Australia, whereas the Swimming Anemone is found off the west coast too. More info HERE.

5. Pretty bubble shells
Rose petal bubble shell (Hydatina physis)
I found two of these lovely bubble shells, partially buried in sand, under a huge rock. They are found in Western Australia too but I have never seen them before. They are just a few cm in length, with large, reddish parapodia flaps. There are some very pretty photos of the animal HERE.

6. There is a good variety of fishes living in Little Bay. These are the ones I could photograph:
Stripey (Microcanthus strigatus)

Pygmy leatherjacket (Brachaluteres jacksonianus)

Blackspot goatfish (Parupeneus signatus) (LEFT)
Blue-spotted goatfish (Upeneichthys vlamingii) (RIGHT)

No idea what fish this could be.

7. I also saw a moon jelly (Aurelia aurita).
This moon jelly is about 8-10 cm in diameter.

8. When I finally decided to get out of water, I saw a cuttlefish swimming in my direction. It let me follow it for a short while and then it moved on and hid itself beneath a huge rock.

Align Center

9. Trash underwater - where did they come from?

A large bottle, probably 3 liter or more in volume

A huge screw driver - it's 2 feet long I think

A golf ball - must have come from the nearby golf course

There were quite a lot of uprooted (detached) kelps

And quite a number of detached sea tulips too. I wonder how it happened.


Denis Wilson said...

Hi Chai.
Lovely shots from your Sydney trip.
What's happening in WA?

Tsun-Thai Chai said...

Hi Denis,

Thanks. I have been so busy that I could hardly find time for blogging. Moving house and having to carry out additional experiments to satisfy my manuscript reviewers are the two main reasons.


glhopman said...

I love that southern anemone! Also, I think i have mentioned it before, but Chai you are so lucky to be able to see those cuttlefish in the wild, the closest i have come is at an aquarium, and i was fascinated by them.

Tsun-Thai Chai said...

Hi Gerrit,

Watch out for my next post. I will put up some photos of cuttlefish I saw at Camp Cove, Sdyney. I will put them up as soon as I have confirmed their identity (species) with a researcher from the east.


glhopman said...

That sounds great! I look forward to seeing them.

Mosura said...

Some great finds there! I especially like the Sea anemones.

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