Tag Archives: Molluscs

Clumpy nudibranch

My local snorkeling spot has been roiled with excitement lately over the appearance of a couple of clumpy nudibranchs. Well, it’s exciting for us.

Nudibranchs (pronounced noo-di-branks or noo-da-branks) are members of the sea slug family. Granted this doesn’t sound too exciting, but nudibranchs are strange and exotic and often wildly colorful. The reason I haven’t posted photos of a nudibranch before is that I’ve never seen one before, let alone got a photo of one. That’s the downside of nudibranchs; they tend to be on the small side. One to three inches is typical for most of them. But clumpy nudibranchs are big, up to 10 inches long. In nudibranch world they’re like King Kong, visible from space.

When they were first spotted, I didn’t see them, but I was on high alert. And then, one day, I saw my first nudibranch. I popped up and called to my wife, only to see her waving at me to come see the nudibranch where she was. So this established that nudibranchs are like buses; you wait and wait and wait, then two come along at the same time. Since then, I’ve seen one or both of them most days I get in the water. Each time I’ve seen either of them they’ve been motoring along at speed, at least for a slug.

Clumpy nudibranchs have some color variations which can be seen in these photos. One has more yellow coloring, the other (second photo) being browner. The order’s name, Nudibranchia, means naked gills. These are the feathery clumps to the rear of the nudibranch. The two protuberances at the front are sensory organs. Clumpy nudibranchs feed mainly on sponges (not the cake variety).

Cliff ladder

My regular walk around Upolu Airport almost always occurs in the afternoon when I walk along the coast towards the east. This usually puts the sun at my back and the wind in my face. Last Friday, I went out in the morning and so walked in the other direction with both the sun and wind at my back. I was surprised by how strange it felt to do this. Approaching spots where I tend to stop and look for things in the water felt weird. I guess it shows what a creature of habit I’ve become.

One other oddity was this ladder propped halfway down the cliff face. I’d never noticed it before. Now, it might be a recent addition, but it’s also possible it’s been there for years because it is somewhat hidden when walking in the opposite direction.

The ladder was probably put there by someone who goes down onto the rocks to harvest opihi. The opihi is an edible limpet that is something of a delicacy in Hawaii. It can be eaten raw or cooked. Some people eat them right after they pry them from a rock. It’s a dangerous business though. They’re found on rocks right at the water’s edge and an opihi picker can easily slip or be swept into the ocean by big, breaking waves.

When I got home, I noticed the figure at the top of the photo. I hadn’t seen him at the time, but he’s an opihi picker who I ran into a little later on my walk.

Posted in response to Bushboy’s Last on the Card challenge. See more responses here.

Crown-of-thorns sea star and its nemesis

crown of thorns

giant triton snailCrown-of-thorns sea stars (Acanthaster planci) feed on coral and, because of this, are considered a menace to the health of coral reefs. Up to a foot-and-a-half across, they can have as many as 19 arms and are covered by venomous spines. If this all sounds like this creature is a nasty piece of work, the good news is that it has not caused extensive damage to the reefs here in Hawaii.

The crown-of-thorns does have predators, one of which is triton’s trumpet (Charonia tritonis). These large triton snails, up to 20 inches long, feed on echinoderms including crown-of-thorns sea stars. When they scent prey, they will take off after it and are considered speedy for a snail. When a triton’s trumpet catches its prey, it grips it with its foot and applies saliva that causes paralysis, which allows the snail to consume its meal without further drama.

Varicose phyllidia

Varicose Phyllidia

This colorful little creature is a sea slug. As with many other nudibranchs, the bright coloring serves as a warning. They’re poisonous and, because of this, have no known predators. One tidbit I found interesting is that nudibranchs like this Varicose phyllidia, don’t produce their own poisons. Instead, they ingest toxins from their prey, such as sponges, and recycle it. So not just yellow and black and pale blue, but green as well.