Monday, March 30, 2009

Cape Peron - John Point

Satisfying! That's how I would describe yesterday's snorkel at John Point, Cape Peron, where I went with Truc, Dhruv and Phil.

There's quite a lot of marine life to check out around John Point. I didn't go very far from shore. Still, even in shallow water of 1 meter of so, I had some interesting encounters.

The highlight of the day, for me, had to be this beautiful dragonet!
I suspect it's an orange and black dragonet (Dactylopus kuiteri) but I will have to confirm that. The fish is about 15 cm in length. It was resting on the sand near some shallow reefs (~1 meter) when I spotted it. It didn't look like an active swimmer. It changed its resting locations a few times to avoid me and in the end decided to disappear into some nearby Posidonia seagrass.

I saw a few sea hares (Aplysia dactylomela) today. This one is really special because of the pink edges of its parapodia ("wings"). I don't remember seeing the same thing in others.

Another interesting critter on the shallow reef - a seaweed decorator crab. In fact I saw two of them yesterday. I have seen a dead one before while beachcombing at Trigg beach. This one is much bigger, with a carapace about 10 cm across. Their camouflage was perfect and they just looked like they have merged into the reef. The red arrows are pointing at the crab's limbs.

And I saw many sea urchins sitting in reef holes.

A few tube worms compete with sea urchins for living space in a reef hole. The white arrows point at the ones that have retracted their crowns of reddish feathery tentacles. The red arrow points the one that decided to show off its pretty tentacles again.

Clifton's zoanthids (Isaurus cliftoni)
These colonial cnidarians, which look like elongated, mini watermelons, are quite common on the shallow reef too. The white arrow points at the two rings of tentacles of one individual.

An eleven-armed sea star (Coscinasterias muricata) that looked like it was trying to pry open the shells of its prey (white arrow).

Southern bailer (Melo miltonis)
I saw this large sea snail sitting amid a patch of wireweed (Amphibolis species). The shell must be at least one-foot long. The first time I saw a southern bailer at Monkey Mia, I was so amazed by its size. It simply looks like a lethal weapon to me! The last time I saw one was at the Penguin Island.

Overall, a wonderful snorkel that I had yesterday. There's so much to explore underwater, e.g. shallow reefs, large outcrops, ledges and seagrass beds. John Point is certainly worth a re-visit!

to Shadowkiller, a Dive-Oz forum member, who told me that the fish is a dragonet - not a scorpion fish as I initially thought.

Monday, March 23, 2009

Rottnest Island - Bickley Bay (5) - Aplysia gigantea

One interesting natural phenomenon I observed during my short stay on the Rottnest Island was the mass stranding of the sea hare Aplysia gigantea.

I remember seeing so many of them when I took a walk on the beach at Bickley Bay one morning - I stopped counting at 20. In fact, when I snorkelled at Green Island, I saw many dead sea hares, probably of the same species, in shallow water too.

This one was about 40 cm long. I didn't try to lift it but it looked heavy.

Another big one that was washed ashore.

I noticed that that they got decolorized after a day or two on the shore.

According to The Sea Slug forum, mass mortality or mass stranding is a natural event for many sea hare species. And the reason could be as simple or natural as the animals reaching the end of their life cycle. For this species, the annual mass stranding and mortality occurs every summer.

The Sea Slug Forum Aplysia gigantea fact sheet
The Sea Slug Forum - Mass mortality
The Sea Slug Forum - Big sea slug from Western Australia

Sunday, March 22, 2009

Rottnest Island - Bickley Bay (4)

The small rock island offshore at Bickley Bay is a good spot to find interesting invertebrates.

Zoanthus sangibaricus
Just a few inches below the surface I found a colony of zoanthids (colonial anemones, if you like). Each individual is about 1 cm or so across. Together, the individual animals make a brilliantly colored mat covering a submerged rock.

And this is where I saw a western slate pencil urchin (Phyllacanthus irregularis) for the first time. The animal looks like some outer space creature to me. This one was hiding in a rock crevice.

Aplysia dactylomela
And I saw a big sea hare too. This one is about 20-25 cm in length.

Correction (22 Mar 09):
Zoanthus sangibaricus was mispelled. It should be Zoanthus sansibaricus instead.

Thursday, March 19, 2009

South Cottesloe Beach - Octopuses, stingaree, stripeys

15 Mar 2009

"These guys were so docile
and they just quietly watched me photographing them
from their lairs."

Just because it's an overcast day, it doesn't mean you won't see much underwater. Besides the black-spotted catshark, I also saw three octopuses!

I only managed to get some good shots of two of the octopuses anyway. These guys were so docile and they just quietly watched me photographing them from their lairs.

And I saw a stingaree resting under a rock in shallow water (1 m or so).
The fish is about 50 cm in length.

Lovely stripeys (Microcanthus strigatus)! Underwater butterflies!
Their bright colors plus the way they move around always reminds me of butterflies!

A male prickly leatherjacket (Chaetodermis penicilligera), a zoanthid colony (Zoanthus praelongus) (again!), and a Western Australia nudibranch (Chromodoris westraliensis)(again!)

All these plus the sighting of the catshark made the day's snorkeling experience a fantastic one!

Wednesday, March 18, 2009

South Cottesloe Beach - Black-spotted catshark

15 Mar 09

"And I must add that it looked SO GOOD
with the way it swung its tail when it swam."

The highlight of today's snorkel was my bumping into a black-spotted catshark (Aulohalaelurus labiosus). Distribution-wise, the fish is confined to only Western Australia and nowhere else in the world.

This can be considered a rare encounter considering the nocturnal habits of the fish. This one is about 60-70 cm in length. And I must add that it looked SO GOOD with the way it swung its tail when it swam.

I watched it for almost ten minutes. It was pretty active. I saw it checking out holes in the reef and also spots underneath some kelps, probably searching for food.

Tuesday, March 17, 2009

South Cottesloe Beach - Other invertebrates

14 Mar 09

Some other colorful marine life that I saw:

While you will often see the khaki sponge at South Cottesloe, there are other sponges in really nice colors, like pink or bright yellow too. Some of them just look like something that you will see in an art class. The arrow above points at some colonial ascidians.

Since the first time I spotted these colonial ascidians, I noticed that these creatures are not that rare on the South Cottesloe Reef.

In fact, I also kept seeing the two creatures below a few times during today's snorkel. I first thought that they were rare on the South Cottesloe Reef - but I was obviously wrong. I am thinking whether I should just forget about taking their photos the next time I see them.

Chromodoris westraliensis
This nudie is about 5 cm in length.

A colony of zoanthids (Zoanthus praelongus)

Monday, March 16, 2009

South Cottesloe Beach - Pretty fan worm

14 Mar 09

This morning I snorkeled at South Cottesloe with a new friend, Wehdi. We spent some time exploring the shallow reef in the south of the second groyne. Later, after he left, I continued snorkeling at the other side of the groyne too.

The wind was not too strong. The water was quite calm and visibility was not too bad, except that it was a little chilly underwater today, as compared to last Sunday.

And today I bumped into a HUGE school of common buffalo breams (Kyphosus sydneyanus). It could easily be hundreds of them! As I was taking photos of them, I suddenly noticed that they were forming a circle around me! It just happened for a few seconds and the circle broke up by the time I set my camera to underwater video mode! But that few seconds were unbelievable! I have seen a southern eagle ray done that but not hundreds of buffalo breams! This was definitely the highlight of today's snorkel.

And I saw a huge school of western striped trumpeters (Pelates octolineatus) on the shallow reef too. Watching a huge school of fish swimming past or scavenging the reef for food is always an enjoyable experience for me.

As I was exploring the reef, I noticed that there were more marine worms, especially tube worms or fan worms around than I initially thought.

The crown of this fan worm (also called feather duster worm) is about 6-8 cm across.

A close-up on the crown:
The feathers are tentacles with tiny hairs (cilia) on them.
The animal uses the beating hairs to drive water through the feathers. The cilia get the food particles in the water and pass them down to the mouth in the center of the crown. The animal not only uses the tentacles to filter feed, but also to breathe!

More common than the pretty feather duster worm on the reef is the Protula species tube worm. This worm is smaller than the previous one which has a pretty crown. This one is 2 cm or so across.

And I also saw this curious fan worm look-alike! The tube seems to be buried within the sponge. Black feathers! For a while, I thought somebody has buried some plastic gadget into the reef.

When I was on my way back to shore, I also spotted a huge school of wordward's pomfrets (Schuettea wordwardi).

I did see a southern eagle ray (Myliobatis australis). But the nearshore visibility was really poor, as you can see from the photo above, so I decided that there's no point taking a shot. On the other hand, I did take a few shots of a squid, but it just didn't turn out alright, so I can't put them up too : (