Monthly Archives: June 2013

Nudibranch protects itself by recycling toxins of others

The egg mass, top, looks like a rose. Their red color comes from the red sponges the Spanish dancer eats. ©2013 Susan Scott

From my Kailua neighbor Marya, who swims with mask and snorkel every morning before work, came this email:

“I saw something that everyone says is impossible … a beautiful dark pink rose, seemingly growing out of the coral. Ridiculous, I thought to myself, must be a plastic rose. So I went down and touched it gingerly, and sure enough, it was soft and felt like a petal. It wasn’t plastic, definitely. It wasn’t like a big rose, but more like the inside two or three layers of a rose. It was so lovely. Could there be such a thing?”

Yes. Marya’s reef rose is the egg mass of the spectacular nudibranch (noody-brank) called the Spanish dancer.

Nudibranchs, also known as sea slugs or nudies, are snails without shells. But lacking a shell doesn’t mean nudibranchs are lackluster. An author of a book I have on Hawaii’s nudibranchs (sorry, out of print) writes that nudibranchs “are among the most beautiful and fascinating animals that live in the ocean.”

nudi

Spanish dancer. Their red color comes from the red sponges the Spanish dancer eats. ©2013 Susan Scott

I agree. And fortunately for us, nudibranchs live mostly in shallow water and are therefore visible to snorkelers, divers and tide pool walkers.

The stunning patterns and colors that most nudibranchs display carry a message: I am poisonous. Don’t eat me.

Nudies don’t make their own poisons, but instead swallow them, gobbling up toxic species, such as sponges, hydroids and Portuguese men-of-war, and recycling those creatures’ poisons for their own protection.

The Spanish dancer and its roselike egg mass are red because the species eats red sponges.

All nudibranchs are hermaphrodites that carry both eggs and sperm. The animals never fertilize themselves, but mate with their own kind sometimes in end-to-end chains. Afterward the creatures lay egg masses in spirals that look like delicate flowers, each species having its own color and shape.

Most nudibranchs are garden slug size or smaller. At 15 inches long the exquisite Spanish dancer is the largest nudibranch the world. It’s found in tropical waters around the world, including Hawaii.

So finding a rose on the reef, Marya, is not only entirely possible, but means that Spanish dancers are doing well off Windward Oahu. It’s also a wonderful way to start the day. Thanks for writing.

eggmass

Another image of a Spanish Dancer Egg Mass. ©2013 Susan Scott


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

©2013 Susan Scott

There’s no place like home for Internet, photo sharing

Tthe 5-foot-long black-tipped reef shark that grazed her belly with its dorsal fin. ©2013 Susan Scott

Even with dozens of South Pacific visions dancing in my head, my own island still dazzles. During a Lani­kai beach walk at dawn last week — the first since my return — I watched great frigate birds and red-footed booby birds glide over my head, tripped over ghost crab sand pyramids and nodded hello to a dozen Homo sapiens come to marvel at sunrise on Oahu. Home rocks don’t get better than that.

Nor does my email. Because I was using a satellite phone program while sailing, I was unable to access my usual email and therefore came back to a treasure trove of comments from readers regarding my Pacific voyaging.

Thank you, everyone, for taking the time to offer encouragement, share stories and gently point out errors.

The mistakes that got the most attention were my misspellings of the place name Tua­motu and the wind force measurement Beaufort, as in the Beaufort scale.

My apologies to motu residents (a motu in French Polynesia is an island inside an atoll’s coral reef) and to Sir Francis Beaufort, the British Royal Navy officer who created the 12-category wind- and sea-state scale.

Another email topic among readers was questioning the lack of photos in my South Pacific columns.

When my underwater camera stopped working, Craig brought with him to the Marquesas a new waterproof Nikon CoolPix that I carried with me on every snorkeling occasion. It took fine pictures, but I couldn’t send them because my sat phone sends text only.

xmastree worm

That’s another joy in being home. I can now share my favorite Tua­motu photos of a fish and a worm.

The fish is the 5-foot-long black-tipped reef shark that grazed my belly with its dorsal fin as it swam beneath me. The Christmas tree worm was one of hundreds that looked trimmed for a holiday, including its purple “hat,” the creature’s trap door called an operculum.

Besides enjoying Oahu’s reefs and beaches this week, I’m also loving my home office, where high-speed Internet sends pictures in a heartbeat and spell-checking is automatic.

Thank you, kind readers, for the warm welcome home.


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

©2013 Susan Scott

Arduous voyage enriched by following variable wind

PAPEETE, Tahiti » The first leg of my South Pacific voyage is over. It took me three months to outfit the boat in Mexico, sail to the Marquesas, explore the Tua­motu Archipelago and get Honu put up in a Tahiti marina. Now I’m going home.

As in all outdoor adventures, the trip had its ups and downs. Some days I wondered what I had been thinking to take this on. This is too hard, I would grumble, wishing I was in Kailua eating takeout and reading Jack Reacher novels.

Other days, as Honu surfed up and down the Pacific Ocean’s giant blue swells, every cell in my body glowed with pleasure.

“Thank you!” I’d call to the wind.

I talked to the wind because on a sailboat, wind is everything. It’s the engine of the ocean, driving not just sailboats and occupants, but the wildlife that lives in, on and above the water.

Some sailors discuss wind and sea conditions in terms of a system that puts numbers to wind and waves. Called the Beauford Scale, it ranges from Force 0 (no wind) to Force 17 (the strongest hurricane).

I don’t use the Beauford Scale because, in recalling my voyages, there seem to be only two conditions: too little wind or too much wind. Of course, there were plenty of perfectly lovely sailing days, but like most trips, in recalling the details, the extremes stand out.

On the passage from Mexico to the Marquesas, I mostly had too little wind. That may sound relaxing but it is not. The sails slap with annoying bangs, the boat pitches and rolls to no rhythm and the skipper and crew get cranky in a hurry.

At those times I used what sailors jokingly call the iron genny (genny is the nickname for a big sail called a genoa), meaning the diesel engine. It’s loud, hot and smelly, but it moved the boat forward. While motoring, however, I had to worry about fuel.

During most of my time in the Marquesas and the Tua­mo­tos, I had the opposite problem: too much wind. The southeast tradewinds were so strong for such prolonged periods that in one month I visited only two islands and two atolls.

But staying at anchor for longer than I planned turned out to be a bonus. In Nuku Hiva while waiting for a wind break, I hiked to one of that island’s (and the world’s) most stunning waterfalls. In a memorable wade in the pool below, freshwater shrimp climbed onto my feet and up my legs.

Spending a week each in the Tua­moto lagoons of Kau­ehi and Faka­rava atolls, I enjoyed snorkeling in crystal water washed in by wind-driven waves that crashed over the fringing reefs.

The lagoon water was so clear and the marine life so stunning that I snorkeled until my fingers wrinkled and my toes got cold.

I also got to see the seabirds swooping and diving in all their glory.

My 37-foot ketch will stay in Tahiti for a couple of months while Craig and I go home to Oahu the easy way, on a plane. We won’t have to worry about how hard or from what direction the wind blows. As sailors like to say, nothing goes to weather (upwind) like a 747.

Once home, I’ll read a Reacher, eat some salad and start planning the next leg of my South Pacific voyage.


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

©2013 Susan Scott

Swimming with reef sharks not fearful, but fun events

Small Black Tipped Reef Shark. Mopelia, French Polynesia, 2006. See picture below for size reference. Click on the image for full sized view.©2006 Susan Scott

FAKARAVA ATOLL, Tuamoto Archipelago » To pass the evenings at anchor here in the South Pacific’s winter, Craig and I often watch movies on the boat’s computer. Last week while shuffling through the dozens of DVDs I’ve collected over the years on my sailboat, Honu, I found one I forgot I had.

“Here’s ‘Jaws,'” I said, thinking we might find this old film funny.

“No,” Craig said. “I’m not watching a cheesy mechanical fish that portrays sharks as monsters.”

I agreed. It’s hard to have a sense of humor about a film that unfairly demonized sharks and produced lifelong shark phobias among millions of people.

We are particularly sensitive to this issue here in the Tuamotos, where residents view sharks as a natural and welcome part of the atolls’ healthy coral reefs.

Visitors from all over the world come to snorkel and dive with Tuamoto sharks, making reef sharks a significant part of the economy.

Since we arrived by sailboat a couple of weeks ago, we have been wading, snorkeling, diving, surfing and kiting with sharks daily. All our encounters have been positive, thrilling but not scary, close but not unnerving.

Last week a 6-foot-long black-tip reef shark passed so close beneath me that I thought I felt a touch of dorsal fin on my belly. But even that wasn’t frightening. The shark nearly ran into me because it was going about its own business of fishing.

The three kinds we routinely see here are the three most common on healthy coral reefs around the world: black-tip, white-tip and gray reef sharks. (There are black-tip and white-tip oceanic sharks, but those are different species.)

When we wade in shallow water, juvenile black-tips swim nearby in twos and threes looking for dinner. The slightest movement, such as raising a camera, startles the little sharks, and in a flash they dash far from the two-legged monsters.

One day Craig dived to a coral head base to explore a cave, and a white-tip reef shark cruised out of an adjacent cave. If it was miffed about having its nap disturbed, we didn’t know it. The shark disregarded the humans milling about and slipped into another crevice to resume its rest.

The gray is a bolder species. During one snorkeling excursion, a 4-foot-long gray reef shark swam straight toward me. After a few seconds of eye-to-eye contact, the shark satisfied its curiosity and disappeared in the deep blue. Silently I thanked the sleek and graceful fish for practically posing for pictures.

Here in Fakarava’s south channel, a World Heritage Site, where currents rush like river rapids in and out of the 200-yard-wide gap, those three species hang out by the hundreds. The nutrient-rich water bathes great walls of multicolored corals from the surface to about 100 feet deep, and those in turn feed and shelter just about every kind of reef fish in the South Pacific.

These well-fed sharks are used to sharing their fish paradise with people and ignore us completely.

To celebrate the joy of swimming on reefs where sharks are respected and admired, and to tune up our sense of humor about fish, tonight we’re going to watch “Finding Nemo.”

shark with legs

Susan’s website guy wtih fierce Black Tipped Reef Shark, Mopelia, French Polynesia, 2006. ©2006 Susan Scott


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

©2013 Susan Scott