Monthly Archives: August 2013

For some sea cucumbers, back ends stave off enemies

Published August 26, 2013 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2013 Susan Scott
Some sea cucumber species release sticky filaments from their tail ends when threatened. ©2013 Susan Scott

Some sea cucumber species release sticky filaments from their tail ends when threatened. ©2013 Susan Scott

Moorea, French Polynesia » I’ve been playing with sea cucumbers.

The way they lie around on the ocean floor, sea cucumbers resemble the vegetables they are named after, and are about as active.

But don’t let that sedentary appearance fool you. These animals spend their lives vacuuming the ocean floor, helping keep the water clear and the reefs clean.

They also defend themselves as only a sea cucumber can, by shooting a weapon from their anus.

At the mouth end of all sea cucumbers are 10 to 30 sticky tentacles that the creature either stretches over the ocean bottom or holds up in the water. When organic particles stick to the tentacles, the sea cucumber pops them, one at a time, into its mouth. As the animal pulls the tentacle out, it wipes off the food.

But the sea cucumber’s anus is equally busy. The creature breathes through it.

To take a breath, the anus dilates and fills with sea water. Closing and contracting the anal sphincter forces the inhaled water into two respiratory trees, the sea cucumber’s version of lungs. It takes six to 10 openings and closings of the anus to fill the trees with oxygen-rich water, each contraction taking about a minute.

The water exits, though, in one big whoosh. When you lift a sea cucumber above the surface, it exhales, releasing one long stream of water from the respiratory trees out the anus.

That’s not all it releases. When irritated or attacked by a predator, some sea cucumber species eject super sticky tubes from the anus like silly string from a can.

The blue-white filaments entangle an attacking crab or lobster in a mass of adhesive threads.While the helpless predator struggles, the sea cucumber crawls away on tiny tube feet, soon regrowing its tacky tubules for the next time it needs them.

Since I learned about this unusual sea cucumber defense years ago, I have picked up countless of these animals to inspect them. Not all species have this weapon, and nothing ever happened.

Tahiti’s reefs, however, are loaded with big, fat, paisley-patterned sea cucumbers that are loaded with sticky string.

The unlucky predator that messes with one of these creatures dies a slow and snarly death. A curious, camera-bearing snorkeler, however, gets a good picture, but also gets her fingers stuck together for the rest of the swim.

The strings delivered no pain, but they sure were a pain to get off my skin.

I’m grateful to the couple of cukes that satisfied my curiosity, and hope rearming themselves doesn’t take too long. Now that I’ve experienced the wrath of a sea cucumber, I will leave them to vacuum in peace.

Marine biologist Susan Scott writes the newspaper column, “Ocean
Watch”, for the Honolulu Star-Advertiser,

©2013 Susan Scott

Lovely, lethal lion fish likely lunched on a jittery friend

Published August 19, 2013 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2013 Susan Scott
A lion fish, not found in Hawaii, hunted near the deck of the Honu when it was in Tahiti. ©2013 Susan Scott

A lion fish, not found in Hawaii, hunted near the deck of the Honu when it was in Tahiti. ©2013 Susan Scott

PAPEETE, TAHITI » For days I admired a pipefish from the deck of my boat, Honu, in this marina where the water is gin clear to 50 feet. The 6-inch-long yellow-banded pipefish was a nervous little thing that spent much of its time hovering behind the rungs of a ladder attached to the dock.

Occasionally the fish ventured out in search of food, drifting crustaceans and fish larvae. But if my shadow darkened the water or my gangplank clunked with a wave, the little pipefish dashed back to its protective rungs.

I was thrilled to have my own pipefish to admire because I’ve never seen any of Hawaii’s six species, which live in deep water, hide in dark caves or hover among camouflaging seaweeds. Like sea horses, pipefish blend so well with their environment that you can look right at one and still not see it.

I mention sea horses because the two are close relatives. Both have long, tubelike snouts that inhale their prey, are slow swimmers and have eyes that move independently to better spot tiny food items. The pipefish resembles a stretched-out sea horse, except it has a skinnier body, fanlike tail and is often decked out in colorful stripes, spots and rings.

Like sea horses, after an elaborate courtship dance, a female pipefish deposits her eggs into her partner’s pouch where he fertilizes them and carries the eggs to hatching. Some males just can’t stop dancing. Researchers have found male pipefish simultaneously carrying the eggs of three females.

As I mentioned last week, while walking my gangplank I nearly fell in the water over the appearance of a 15-inch-long lion fish, its fins nearly breaking the water’s surface. This stunning carnivore is native from Australia to the Marquesas, and from Japan to New Zealand, but is not found in Hawaii.

Lion fish weren’t found in the Atlantic, either, until humans gave them a lift. The species, Pterois volitans, is now common from Florida to New York and Bermuda where it preys on native fish not adapted to this crackerjack stalker.

But even those that know the danger can be in trouble when a lion fish goes hunting.

Slowly my lion fish swept the coral wall along my dock, fanning its lovely, venomous fins to flush out small fish and invertebrates.

It’s a sight to behold under any circumstances, but that fish gave me time to fetch my camera, shoot some pictures and still have minutes to marvel.

It also, I think, ate my pipefish. I never saw it again.

I consider my pipefish and lion fish sightings as extraordinary gifts from the South Pacific. And I haven’t even left the dock yet.

Marine biologist Susan Scott writes the newspaper column, “Ocean
Watch”, for the Honolulu Star-Advertiser,

©2013 Susan Scott

Walking the plank in Tahiti reveals an aquatic pageant

Published August 12, 2013 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2013 Susan Scott

PALETTE, Tahiti » After a two-month rest at home on Oahu, I’m back in Tahiti preparing my 37-foot sailboat, Honu, for a six-week voyage through the Society Islands, part of French Polynesia.

Polynesia is the key word for me, because Tahiti carries the same warm Polynesian spirit that makes Hawaii such a fine place to call home. Also, people here know the word Honu, a term that means green sea turtle in Tahitian as well as in Hawaiian. We are turtle fans together.

Tahiti gets a lot of negative press among cruising sailors, a judgment I find so unfair that I’ve become as staunch a defender of this stunning island as I am of Oahu.

Look past the crowds of Pape­ete (population about 140,000), the traffic congestion and the high cost of living and it’s easy to see how Tahiti became synonymous with paradise.

The island’s rugged green mountains plunge into clear, turquoise water packed with coral reefs. Here in Marina Taina, about five miles from Papeete, I don’t even have to get in the ocean to be astonished by Tahiti’s marine life.It’s like living in the aisle of the Waikiki Aquarium’s South Pacific exhibits.

Honu is parked in a style called Med mooring, common here and in the Mediterranean. In this system, instead of finger piers, rubber pillows called fenders separate boats at their sides. There are variations of Med mooring, but generally the skipper drops an anchor off the bow, backs the boat to the pier and ties the stern there.

This is tricky to pull off gracefully, but that’s not the hardest part for me. To protect the back of the boat from getting banged up during tide changes, ocean swells and motorboat wakes, the stern must be tied 6 to 8 feet off the concrete pier.

This means that to get ashore I must walk the plank, a long, narrow, always-moving board lent by the marina. Each journey to dock and back is an adventure that comes perilously close to a swim.

Last week, however,I came to look forward to my plank walks. Below my shaky knees swam a rare pipefish (a sea horse relative), a 15-inch long lion fish as big around as both my outspread hands and a dozen kinds of damselfish and butterflyfish.

This confetti parade of fish was there feasting among the dock pilings’ growth of pink and yellow cauliflower corals packed together like a lush vegetable display.

I called to a marina worker to come see Honu’s stunning visitors. We hung over the edge of the dock watching the lion fish fan its pink, blue and brown fins as it herded prey along the coral wall.

“C’est beau,” Sam said, agreeing with me that the scene was truly beautiful.

After the lion fish disappeared, Sam watched me struggle with my flexing wooden gangplank and later returned with a wider, more stable aluminum one that makes my life — and fish watching — much easier.

Aloha is not a Tahitian word, but the people here sure live its spirit. It’s easy to see why Fletcher Christian of HMS Bounty fame didn’t want to leave.

Marine biologist Susan Scott writes the newspaper column, “Ocean
Watch”, for the Honolulu Star-Advertiser,

Dragonet ‘discovery’ proves ocean’s teeming surprises

Published August 5, 2013 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2013 Susan Scott

A longtail dragonet is camouflaged in two feet of water off Waia­lua. ©2013 Susan Scott

I had a grand moment recently when I discovered a new fish. Well, not discovered discovered. Other fish enthusiasts know this species, but it was new to me and that made my day.

I prefer to snorkel in water 2 to 4 feet deep because the light is good and it’s easy to brace myself to shoot pictures. Shallow water is where I’ve had countless memorable moments. As long as they’re under it, many fish and invertebrates don’t seem to care whether the water is 3 feet deep or 30.

My shallow-water habit paid off last week when I saw the sand beneath me move, and as if shedding Harry Potter’s invisibility cloak, a fish appeared. It had big knoblike eyes that moved independently as it watched me. Fins stuck out all over the place, and the fish’s tail stretched out nearly as long as its body.

The 10-inch (with tail) beauty eyed me warily for a minute, allowing me to take its picture. Good thing I got proof of my rare sighting because as quickly as the fish appeared, it disappeared.

Even with a photo, I didn’t know where to start researching this odd fish. So I emailed my photo to John Hoover, author of my favorite local fish guide.

“Do you know what it is?” I wrote.

“Longtail dragonet,” he wrote back almost immediately. “Page 86. Nice find!”

Dragonets (sometimes spelled dragonettes on the Internet) are a family of about 160 species of bottom-dwelling fish found in tropical and subtropical seas. Of Hawaii’s eight dragonet species, seven, including the longtail, are found only here.

Longtail dragonets’ sand-colored camouflage is one reason these fish are rarely seen. But besides matching the sand and rubble they call home, dragonets also rest beneath it. When alarmed, they can bury themselves in the blink of an eye.

I thought I had never seen a one before, but upon reading about this family, I realized I had seen one in Palau. The mandarinfish, about 2 inches long and arguably the most colorful fish in the world, is also a dragonet. Type mandarinfish in your search engine and prepare to be astonished.

The longtail dragonet, which reaches 12 inches long, is a real dragon compared with its kin. Most dragonets are less than 3 inches.

If you’re wondering how a woman can study marine biology at UH, snorkel and dive Hawaii’s waters for 30-odd years and still find a fish she can’t even look up, well, that’s the charm of the ocean. I stick my face in it, and like Forrest Gump’s box of chocolates, I never know what I’m gonna get.

Marine biologist Susan Scott writes the newspaper column, “Ocean
Watch”, for the Honolulu Star-Advertiser,

©2013 Susan Scott