Category Archives: Marine Invertebrates

Helmet urchins on the coast

This scene drew my attention because of the smooth, round rock nestled into a matching recess in the shore (bottom left in the top photo). It was when I zoomed in (bottom photo) that I noticed the large number of helmet urchins stuck to the shoreline. These cheerful-looking purple blobs live in the harsh tidal zone, and area of crashing waves and surging water. They feed on algae that grows there.

In the middle photo, an a’ama crab skirts a colony of urchins. When the tide comes in, the crab will move to higher ground, but the urchins will stay put, tenaciously defying everything the ocean throws at them.

Uplifting moments from 2020

This week’s Sunday Stills challenge theme is ‘Your 2020 Retrospective.’ See more responses here. Also posted in response to Becky’s January Squares challenge theme of ‘Up.’ See more responses here.

In this retrospective I’ve focused on events and photos that were uplifting for me during the difficult year that was. Most of these photos haven’t run before, but were taken at the same time as those in posts that ran in 2020. Links to the original posts are at the end of the captions.

Varicose phyllidia

This varicose phyllidia is a small nudibranch, which I saw several times over the course of a week or so. Apart from being a lot smaller than the clumpy nudibranchs I saw a couple of months back, the varicose phyllidia has gills under the mantle skirt rather than in an exposed, wavy clump.

This one was two to three inches long. In the middle photo, the tiny white-spotted toby and small brown surgeonfish give a sense of scale.

Day octopus squabble

A couple of days ago, I saw an octopus while snorkeling. It was on a vertical face of rock and when I showed up it slipped around the corner out of sight. I followed and could see it had gone into a recess there. I saw a tentacle moving and then, moments later, a round white thing appeared, a tentacle clasped around it.

I was mystified. I thought it might be the remains of an urchin or something. The white globe disappeared back into the depths. Moments later it appeared out of the side of the recess and it quickly became clear that the round white balloon was the head of another, completely white octopus. This white coloration is adopted when an octopus is feeling aggressive or threatened.

After a brief flurry of tentacles the white octopus disengaged, shot away a short distance, and changed color again as it landed on a rock. The octopus I’d first seen appeared again at the entrance of the recess. There was a little more to and fro before the evicted octopus gave up and moved away and the first octopus slipped back into the depths of the recess. My take on this was that the octopus I saw first wasn’t happy to find the other octopus in its lair and turfed it out.

The top photo shows the evicted octopus gathering itself after being run off. The second photo shows it on the move, still with the white coloration. The third photo shows the victor in the dispute, looking a little smug if I may say so.

Chained salp

Yesterday, when I was out snorkeling, I was spotted this entity hanging in the water. When I first saw it, I thought it might be a pyrosoma. I was lucky enough to see one of those last year, which I posted about here. Pyrosoma are colonies of many individual tunicates and this new sighting looked somewhat similar. But where that pyrosoma looked like a gelatinous tube with little purple dots in it, this tube was longer, thinner, and had much larger, and clearly visible, brown spots in it.

After some research, I’m pretty sure this is a chained salp. Like pyrosoma, chained salps are colonies of individuals. The individuals have a heart, gills and a spinal cord, which makes them quite advanced in evolutionary terms. They move around by pumping water through their bodies. When they form chains, the individuals in the chains communicate with electrical signals so the the chain moves in harmony.

Typically, salps are creatures of the open ocean, and not often seen in Hawaii, so I feel quite fortunate to have seen this one.

Kinda grizzly

If you like graphic violence, you’re at the right place today. This is a triton’s trumpet sea snail devouring a cushion star, which has been turned on its back. These snails are the largest in the island and feed on echinoderms, which include stars, cucumbers, and urchins.

Posted in response to Becky’s October Squares challenge theme of ‘Kind.’ See more responses here.

Sneaky day octopus

I was almost done with my swim yesterday when I noticed this small day octopus sneaking into this crack. It was shallow there so I got a decent photo of the octopus watching me. Then I swam on a few feet. The octopus, as they do, emerged from its hideaway, so I quickly turned and got the second photo. I can be kind of sneaky, too.

Posted in response to Becky’s October Squares challenge theme of ‘Kind.’ See more responses here.

The morning dip

A whitetip reef shark passes below looking, I think, for a quiet place to get some rest.
A fourspot butterflyfish swims by a patch of cauliflower coral, some living, some dead. There are two spots on each side, but this fish was very small so the second spot was still filling in as space allowed.
A blue goatfish cruises by.
A green linckia sea star and lobster molt. Most green linckia have five arms but can have four or six. They’re able to reproduce by detaching an arm which will eventually develop into a new star.

This week’s Friendly Friday challenge theme is ‘Morning Rituals.’ See more responses here.

Most mornings, I try to get in the water, as conditions and schedules allow. Morning is the best time for snorkeling as the water is usually calmer before the wind picks up as the day wears on. Visibility can vary from day to day and it can help to check surf reports to see if there are any swells moving in. But calm water doesn’t guarantee good visibility just as swells don’t always mean bad visibility. There’s only one way to be sure and that’s to jump in.

My favorite thing about snorkeling is that every day is different and I never know what I’ll see. Going to the same spot means I become familiar with some of the regulars, but there are always transient creatures passing through including rays and dolphins. And while those big creatures are great to encounter, it’s equally interesting to watch the activities of smaller fish and marine invertebrates.

It’s a rare day indeed that I don’t emerge prattling on about something I saw while I was in the water. And on those rare days, well, I’ve still had a good swim to set me up for the day ahead.

It wasn’t until I processed this photo of a goldring surgeonfish that I noticed the stocky hawkfish resting motionless below it.