Tag Archives: pencil urchin

Snorklers see red with slate pencil sea urchins

Published July 8, 2017 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2017 Susan Scott

A slate pencil sea urchin is tucked into a tight place for a daytime nap. This type of urchin can be found in the Indian and Pacific oceans. ©2017 Susan Scott

Last week when I arrived at one of my favorite snorkeling spots, I found fishermen lined up near the waterline. To avoid their hooks and lines, I had to enter the water far down the beach and swim in an area different from my usual.

It caused me to see red. Not red as in anger, but red as in scarlet.

The outer reef in this North Shore area takes a beating from the surf every winter, and is therefore riddled with cracks and crevices. Wedged tightly into one of the smaller holes, in about 3 feet of water, was a large, red slate pencil sea urchin.

Slate pencil urchins are found throughout the Indian and Pacific oceans, but they are only abundant in Hawaii’s clear shallow waters. Lucky us. In some island areas these sea urchins decorate the reef like glorious gaping flowers. To see some of Hawaii’s exquisite red sea urchin gardens, click here.

Slate pencil urchins have blunt, paddlelike spines that reminded someone of the chalk sticks people once used to write on slates. Unlike their cousins, the long-spined black sea urchins, or wana, the slate pencil’s blunt spines can’t pierce human skin.

Even so, for the sake of the animal, you don’t want to touch these red beauties. Covering each of the creature’s “pencils” is a thin layer of tissue that inhibits the growth of algae and other marine organisms. Handling these animals, even gently, can damage their natural protection.

At night the slate pencil sea urchin uses its suction-cup tube feet to walk around the reef, scraping up algae with its underside mouth. During the day the creature tucks into reef holes for rest and protection.

Really tucks in. Often the animal looks so crammed into the space with its paddlelike spines pointing every which way, it’s hard to imagine how the urchin got in there and, come dusk, how it will get out.

These creatures are more flexible than they look. The sea urchin can’t bend its spines, but can move them in most any direction because each is attached to the body with a movable ball-and-socket joint.

Red isn’t a common color on the reef. Because the sun’s red wavelength doesn’t penetrate water very far down, red looks red only in shallow water. At about 30 feet deep, red looks brown. Continue to 60 feet and below, and red turns black.

Most slate pencil sea urchins hang out on the top and sides of shallow reefs, displaying their stunning paddles for all to see.

I admit that I get grumpy about fishermen casting into shallow reef areas, because when their lines get stuck, the anglers cut them, leaving yards of monofilament to wrap around coral heads and strangle turtle flippers. This time, though, the shoreline anglers gave me a gift: a new place to see red.

Humans have decimated pencil urchin population

Published July 8, 1996 in the “Ocean Watch” column, Honolulu Star-Advertiser ©1996 Susan Scott

LAST week, while taking an evening stroll down the outside pier of the Ala Wai Boat Harbor, I spotted a big yellow-and-white catamaran in the transient space. Wondering where it came from, I peeked around its stern to read its home port.

pencilNothing was written there. But what I did see in that boat’s cockpit stopped me in my tracks. Disgusted, I turned to leave, then went back and looked again. Later, I brought a friend there and showed him the sight.

I couldn’t stop thinking about these people’s little collection, and as you can see, I am now even writing about it.

The “it” is this: Two exquisite, fully grown slate pencil urchins, dead as doornails, sat drying on the deck near some fins, masks and snorkels.

Some might argue that perhaps these folks found the urchins already dead on a beach and simply brought them aboard. I have trouble believing that. These urchins hide in cracks and crevices during the day, usually in wave-swept areas. At night, the animals leave their shelters and graze on algae. It’s uncommon for these animals to just drop dead out in the open, then wash ashore fully intact.

More likely, some snorkeler from the boat thought they were pretty, dragged them from their shelters, then killed them by bringing them aboard.

When these urchins dry out more, they turn dark brown, the spines fall off and the whole thing stinks like mad. These sailors will end up with a pile of rotting flesh and drab calcium carbonate paddles for a trophy. Which, no doubt, they will then toss overboard.

OK, so I’m being shrill over a couple of sea urchins. But this kind of thoughtlessness gets my blood pressure up for several reasons. First, it’s one of the things that gives boaters a bad name. These incidents stick in people’s minds, then come up again when boaters ask for favors, such as additional mooring space.

Another reason this incident galls me is that this kind of destruction is so useless. No one wants to eat these animals, and they never cause anyone harm. Yet they are killed by the dozens.

One source says that slate pencil urchins were once common on most of Hawaii’s reefs. Attracted to these animals’ unique shape and color, reef visitors brought them ashore only to later discard them on the beach. The result, of course, is that these urchins are now scarce in all the areas readily accessible to humans.

In ancient Hawaii, people called these urchins punohu and used their spines as pencils. The rust-red color easily rubs off on rocks and slates.

Sea urchins may look like some sort of weird pincushions, but these living, breathing animals are intricate parts of healthy reef ecosystems. They deserve to live.


Marine biologist Susan Scott writes the newspaper column, “Ocean Watch”,
for the Honolulu Star-Bulletin, www.starbulletin.com