Peter and Linda have been snorkelling at Woody again. Here are some of Peter’s pics of their latest discoveries.
Not a nudibranch, but the sea hare Dolabella auricularia
I’d already seen Sebadoris fragilis at Flat Rock, Ballina, but it’s always a joy to see any nudi, anywhere, anytime.
This one was found by Peter and Linda, snorkelling off the rocks at Woody Head. Thanks to Peter for the photos.
The rock pools at Flat Rock have been covered in sand for a few months, but gradually the sand is clearing and seaweeds and algae (with associated fauna) are coming back. The lowest tides of the spring give a good opportunity to go further out on the platform than usual.
Here’s a nudibranch I’d not seen before, although they are apparently common – Sebadoris fragilis. They grow up to 12 cm and this one was about 8 cm long. (IDs courtesy of Nudibranchs of the Sunshine Coast).
There was only one Discodoris fragilis, but over a dozen Plocamopherus imperialis – breeding time? They can grow up to 10 cm, but this one wouldn’t have reached 2 cm.
Below is possibly Kaloplocamus acutus – if it is, it’s way off the 6 cm length of adults. This one might have been 1 cm.
It was definitely breeding season for the limpets …
… and the cartrut shell (Dicathais orbita). The egg cases are yellow when ‘fresh’ and go purple after a while. (The purple cases below are in front of and separate from the yellow cases behind.)
Black feather duster worm …
We saw three small sharks resting in the crevices, but it was impossible to get decent shots because the water was rippling through fast. One was a clearly a wobbegong but the other two were different.
There were over a dozen sea hares, perhaps in preparation for mating, too. They form mating chains, one behind the other.
A lot of birds were resting on the platform. It annoys the heck out of me when people allow their dogs to run free there – no dogs are meant to be on the platform, and only dogs on leashes on the beach. The migrating seabirds need rest and refuelling.
A pair of beach stone-curlews (Esacus magnirostris, aka beach thick knees because that’s what they have) flew quickly past, crying their curious call. It was the first time I’d seen this species in the wild.
This is either the grey-tailed (Heteroscelus incanus) or the wandering (Heteroscelus brevipes) tattler. The grey-tailed is more common.
I think the birds below are sandpipers, but there are a lot that look alike and I haven’t worked out how to distinguish them yet. Any ideas appreciated.
We went to Woody Head on Saturday for the regular folk music/dance event that our friends have been doing for over 20 years, but only for the day. It’s a good spot for snorkelling and looking in rock pools (nudibranchs!), as many of my previous posts attest.
We weren’t there Sunday but Peter and Linda were in the water as usual, and Linda found a Spanish dancer (Hexabranchus sanguineus). I’ve longed to see one in the wild and managed to while snorkelling in the Lord Howe Island lagoon, but it was a long way down so I didn’t get a proper look. (All photos by Linda Scharf)
During daytime, the Spanish dancer hides away from the light in the crevices of its natural habitat to only come out late at night. It feeds on various species of sponge. Like all nudibranchs, it is hermaphrodite and its bright red to pink egg ribbon has a spiral shape related to the size of the animal so relatively large. The latter is coveted by some other species of nudibranch as Favorinus tsuragunus or Favorinus japonicus. The Emperor shrimp, Periclimenes imperator, is a commensal shrimp that is commonly found living on Hexabranchus sanguineus.
Well done, Linda. Next time I’m staying overnight!
Peter has been busy with his underwater camera. He found some nudibranchs while snorkelling at Woody Head, northern NSW. Many thanks to Peter for letting me use his photos.
I’m sure you know already but, in case you don’t, the name ‘nudibranch’ means ‘naked gill’. Nudis are (usually) tiny molluscs that are brightly coloured and apparently taste ghastly to potential predators (at least according to Ed Ricketts, who had a chew). They have been measured at 6 mm to 31 cm (0.25″ to 12″ for you imperialists).
National Geographic explains:
They are carnivores that slowly ply their range grazing on algae, sponges, anemones, corals, barnacles, and even other nudibranchs. To identify prey, they have two highly sensitive tentacles, called rhinophores, located on top of their heads. Nudibranchs derive their coloring from the food they eat, which helps in camouflage, and some even retain the foul-tasting poisons of their prey and secrete them as a defense against predators.
Nudibranchs are simultaneous hermaphrodites, and can mate with any other mature member of their species. Their lifespan varies widely, with some living less than a month, and others living up to one year. …
Some nudibranchs are solar-powered, storing algae in their outer tissues and living off the sugars produced by the algae’s photosynthesis.
The first is Hypselodoris maritima …
It’s like this. I was standing in a rock pool at Flat Rock, Ballina last weekend. Low tide. Good critters, like this one …
The new moon brought a very low tide, so off to Flat Rock. Fortunately it’s recovered from all that sand over winter, and there were lots of animals, shells and so on in the rock pools.
I was especially pleased to see this nudibranch (Austraeolis ornata), apparently a common one but I’d never seen it before. I only spotted it because I stopped to admire a Peron’s side-gilled sea slug that happened to be next to it.
Best Christmas present! This glaucus washed up by the heavy seas courtesy of the cyclone up north …
Glaucus atlanticus, a nudibranch, floats on the surface of the ocean, along with other members of the “blue brigade“. It can wriggle a bit, as this one was in its pond, but is mostly at the mercy of wind and currents, as are its confederates.
It feeds on the bluebottle, Physalia physalia, and moves the bluebottle’s stinging cells from its stomach into its own tips, so anything trying to eat it will get a mouthful of bluebottle stings. Other nudibranchs do this: see Evolution Happens for a description.
This one was about 3 cm long. The hole on the left side is a reproductive pore. Glaucus is a hermaphrodite.
I don’t see them very often, and this one was a special surprise on Christmas morning. Thanks, Mother Nature!
I used to work in the Marine Invertebrate section of the South Australian Museum, and the curator and his assistants (including me) would go on field trips to get specimens, especially for our marine tank. This was not on display to the public, but I quickly learnt that marine tanks are fussy to look after and can turn into a stinky mess overnight.
We’d get rocks with lots of weeds and put them in the tank. It was always exciting to come in the next morning and see what had crawled out – especially nudibranchs.
We’d bottle them up in formaldehyde and send them off to the expert at Museum Victoria in Melbourne, Bob Burn, who often discovered that many of these were new to science. He had the fun and privilege of describing and naming them. There’s no windowii, though.
It’s still exciting for me to see a nudibranch, and these days there are many websites, books and CD-ROMS available to help with ID.
Here are two new – for me – nudibranchs from Flat Rock last weekend. They were both about 2 cm long.
Around spring equinox, the low tides are lower than usual. The sand deposited by winter storms is starting to be washed off the rocks, and there is now lots of life in the Flat Rock rock pools, although surprisingly few humans on the beach, considering it is the start of a fortnight of school holidays.
I can’t resist a nudibranch, even though I’ve already posted another photo of this one, Rostanga arbutus …