Monthly Archives: November 2015

These jellyfish hardly sting but a snorkeler is entranced

Published November 30, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott

The golden jelly has eight arms, each ending in clublike extensions that contain mild stinging cells. ©2015 Susan Scott

The golden jelly has eight arms, each ending in club like extensions that contain mild stinging cells.
©2015 Susan Scott

I’m home from Palau, but as I recall my excellent two weeks of snorkeling there, one image pops out: floating mesmerized above millions of jellyfish in a landlocked marine lake.

Called Ongeim’l Tketau (also known as Jellyfish Lake), Palau’s famous lake contains seawater that flows in and out through channels and fissures in its limestone island. As a result, the lake’s water rises and falls with the tides in the surrounding lagoon.

Jellyfish Lake is special, but not because it’s Palau’s only marine lake with jellyfish. The island nation hosts more than 50 such lakes, five containing jellyfish. All are the same species, Mastigias papua, but dissimilar enough that scientists gave them subspecies names, each honoring Palau’s five elected presidents.

DSCN2406

Ongeim’l Tketau, however, is the only lake open to visitors. Tourists come from around the world to swim with its mass of up to 13 million golden jellyfish migrating daily across the 14-acre lake. (Waikiki’s Hilton Lagoon is 5 acres.) It’s a myth that these jellyfish have lost their sting. True, the creatures house algae in their tissues and get carbs from the plants. But the jellies also need protein and, like their coral relatives, have small tentacles that sting and kill tiny drifting animals that live in the lake.

Rocket jelly

The story that the jellyfish don’t sting comes from the fact that their stinging cells, called nematocysts, are too weak to penetrate human skin except, possibly, in sensitive places such as lips. Even then most people just get a tingle. Or nothing. When an adult golden jelly, about 4 inches across, brushed my lips, I felt nothing but joy. It was like getting kissed by a mobile marshmallow.

The jellies cluster together because they follow the sun, giving their gardens the light they need to make sugars. (The creatures’ color is their algae’s color.) At night the jellyfish rest, but come morning they’re on the move again. In Ongeim’l Tketau, the jellies travel about a half-mile per day, swimming east in the morning and west in the afternoon. By stopping where shadows hit the lake’s edges, the jellies avoid their major predator, a native white anemone that grows on fallen branches and mangrove roots along the lake’s walls. At the slightest touch, the anemone stings the jellyfish and eats it.

Susan in Jellyfish Lake

To give all their plants equal time in the sun, the pulsating creatures twirl every which way as they migrate, performing a slow-motion ballet. Watching this dance of the golden jellies while floating and breathing through a snorkel is like taking a tranquilizer. Mastigias papua etpisoni is my kind of drug.

DSCN2385DSCN2389

Pajama cardinal fish makes Palau snorkeling a pleasure

Published November 23, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott

Pajama cardinal fish rest during the day and hunt tiny fish at night. ©2015 Susan Scott

Pajama cardinal fish rest during the day and hunt tiny fish at night. ©2015 Susan Scott

PALAU » My two weeks of snorkeling in Palau are nearly over, and even though my husband, Craig, isn’t here, I can hear him ask the question he asks at the end of every adventure: What was your favorite part of the trip?

It’s always hard to choose one thing, but it’s particularly hard here with rock islands surrounded by coral reefs loaded with so many fish and invertebrates, my brain can’t take them all in. But when I close my eyes and recall my days here, one image pops out: the little fish in pajamas.

Palau hosts a reef species called the pajama cardinal fish, native to the western part of the tropical Pacific. The fish is so named because a black band around its middle looks like a waistband holding up red, polka-dotted pajama bottoms. A bright yellow top punctuated with big eyes and a body studded with permanently erect fins completes the image of a fish so adorable you want to give it a good-night kiss.

Pajama cardinal fish are nearly as tall as they are long, with adults growing to 3 inches. Even though small, the fish are easy to spot because five to 10 individuals often hover together outside branched corals. If you startle them, the fish dart into the safety of the coral’s arms, peeking out to see if the coast is clear.

But these cuties don’t startle as easily as other small fish. Usually, we found groups of pajama cardinal fish hanging like mobiles, the individuals motionless and facing the same direction.

“They look sleepy,” said one of my snorkeling companions.

“Of course they do,” my friend Lani said. “They’re in their pajamas and having a sleepover.”

The fish were inactive because the world’s 300 or so cardinal fish species rest during the day. At night they perk up to hunt tiny fish and crustaceans.

As if their appearance isn’t endearing enough, pajama cardinal fish have a remarkable method of reproducing.

The male guards the female as she lays her eggs. After fertilizing them, he scoops the whole load into his mouth. It’s then the female’s turn to stand guard and chase potential predators from her mate.

In three to four weeks, well-developed fry pop out of dad’s mouth. The male can’t eat while mouth brooding and can swallow up to 30 percent of the offspring. Oops.

As you might expect, pajama cardinal fish are favorites for home aquariums but they don’t have to be taken from the reef. Pajama cardinal fish are so mellow, they breed readily in tanks.

I like Craig’s question because it causes me to reflect on a trip’s highlights while they’re still vivid. Even so, I struggled in choosing pajama cardinal fish. Palau is all highlights.


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

©2015 Susan Scott

A snorkeler adrift in Palau finds underwater rewards

Published November 16, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott

A crinoid walks along the sea-bed in the waters of Palau. ©2015 Susan Scott

A crinoid walks along the sea-bed in the waters of Palau. ©2015 Susan Scott

PALAU >> In some of my favorite snorkeling spots here in Palau, I don’t have to stroke my arms or even move my fins to see vast stretches of coral reef. With Palau’s tidal range of 6 to 7 feet, and two high and two low tides daily, the current along the edges of deep channels is sometimes strong enough that we snorkelers have little choice of where to go. There’s nothing to do then but relax and let the ocean have its way.

Drifting effortlessly above colorful coral reefs is fantastic, but it’s hard to get a good look at a particular organism. By the time I turn around and swim up-current, I’ve often lost sight of what I wanted to look at. Also, there are no handholds to help a person steady a camera. Touching coral is a strict no-no, and it’s almost all coral.

But drift snorkeling has a big plus. Moving water offers free delivery to suspension feeders such as sea fans, soft corals and other wonders. Among those wonders are feather stars, also known as crinoids.

Crinoids (not found in Hawaii) are starfish and sea urchin relatives but have a shape and lifestyle all their own.

Crinoids get to touch the coral. The black, green and orange creatures stand in the open on coral heads, positioning their multiple feathery appendages in the current.

Tiny tube feet tipped with sticky mucus stick out from both sides of each arm. When the moving water brings tiny plants and animals to the crinoid, they get stuck in its glue.

This starts the crinoid’s ingestion assembly line. The outer tube feet flick the food to inner tube feet that cover it in slippery mucus and then deposit the catch in a groove at the center of each arm. There tiny hairs act like conveyor belts, transporting the meal to the creature’s mouth at the center.

Although they can walk and even swim, most crinoids find a spot they like and park there. Because crinoids have rootlike feet, a walking feather star looks a mutant flower searching for a sunnier spot.

Compared with 500 million years ago when they covered the ocean floors, crinoids are rare today. But their fossils are not. Among other places, they’re abundant in the Midwest. Missouri’s state fossil is the crinoid.

Drift snorkeling here isn’t scary because at the end of the channels, the water spreads out and the current stops. In addition, the boat goes with you. Palau’s boat drivers follow snorkelers and divers, so you can get out of the water when you like.

I’m soon starting my second Palau tour as a naturalist for the Oceanic Society, and even though I don’t know what I’ll see, I know one thing for sure. I will go with the flow.


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

©2015 Susan Scott

Palau is a wonderful world and the plovers are a plus

Published November 9, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott
The water between the islands of the Republic of Palau is full of coral, marine mammals and other wildlife. <br>©2015 Susan Scott

The water between the islands of the Republic of Palau is full of coral, marine mammals and other wildlife. ©Susan Scott

KOROR, Palau >> Because I flew to this island nation directly from Australia’s Great Barrier Reef, my expectations were high. And sure enough, before I even got my feet wet, I saw an animal that moved me to tears.

Standing on the concrete wall of a boat ramp where I was about to take my first plunge in Palau waters was a Pacific golden plover.

Hello, kolea! These plovers aren’t the same individuals we see in Hawaii, but they’re the same species. Palauans called them “derariik.”

Because plovers and other migratory shorebirds nest in the Arctic, the ones that winter here make longer annual round-trip flights than our kolea. The 10-inch-long birds can’t store enough fat for such long journeys — if they did they couldn’t fly.

The plovers that winter here and farther south make refueling stops in the rice fields of Japan and possibly other parts of Asia. To see that graceful bird performing its familiar ballet at the Palau shoreline gave me such joy that I thought, “If I see nothing else here, I’ll be happy.” Of course, I know that during my two weeks here I will see countless other wonders. Palau was named a UNESCO World Heritage Site in 2012 for good reason.

The Republic of Palau consists of 586 islands that lie about 400 miles north of the equator, similar to the latitude of Palmyra Atoll. Situated in the western part of Micronesia, Palau is roughly between and a bit south of the Philippines and Guam.

Because the total land area of Palau’s islands is 176 square miles, most of Palau consists of water. This is no ordinary water.

More than 600 species of hard and soft corals grow here between green toadstool-shape islands. They are so eye-popping that one of my snorkeling companions said she felt as if she were in a Disney movie.

A surrounding barrier reef protects the inner islands from offshore waves, and three oceanic currents converge here, supporting a vast variety of marine life. These combinations make Palau a diving, kayaking and snorkeling paradise.

Palauans are rightly proud of the unique beauty and nature of their nation, and work to protect it. Palau was the first country, in 2009, to create a shark sanctuary, and in 2010 the government made Palau’s waters a marine mammal preserve.

Fishing is banned in large areas, licensed guides are mandatory and park fees go to maintaining tour facilities. A wildlife preserve called the 70 Islands is off-limits to everyone, giving turtles, dugongs and other marine animals a human-free haven.

When I returned from my first amazing snorkeling excursion here, my plover was still dancing on the wall. I take it as a sign of great things to come.


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

©2015 Susan Scott

 

Violet snails build their own bubble rafts and float away

Published November 9, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott
Violet snails shells are left behind by animals that survive by eating Portuguese men-of-war.©2015 Susan Scott

Violet snails shells are left behind by animals that survive by eating Portuguese men-of-war. ©2015 Susan Scott

AIRCRAFT BEACH, EURIMBA NATIONAL PARK, Australia » For me, beach walking is often as rewarding as snorkeling. Sure, marine animals lying on beaches are dead or dying, but that means I can pick them up or turn them over and admire to my heart’s content. The long-dead animals I found stranded on this 2-mile-long sand beach, suitable for small plane landings, are the largest violet snail shells I’ve ever seen, nearly 2 inches long and an inch high. The exquisite shells, lavender above and purple below, lay 50 or so feet above the high tide line, suggesting that storm winds drove the snails toward shore and high waves spit them out. Most violet snails have better luck. Healthy ones float offshore, upside down, on self-made bubble rafts. Some believe that the snail agitates water with its foot to make bubbles. Another theory is that the snail blows bubbles from air it has taken into its shell. In either case, the creature secretes mucus from its foot to coat its bubbles, creating a rubbery raft.

It’s a precarious existence. To lose the raft is to sink to the bottom and drown. These air-breathing snails can’t swim.

Nor can they steer. Throughout the world’s tropical oceans, violet snails and other members of their drifting community, including Portuguese men-of-war (called blue bottles here in Australia), are at the mercy of winds and currents. That’s why during strong onshore winds, we find both species stranded on beaches.

Unlike us, violet snails don’t get a sting when they bump into blue bottle tentacles. They get a meal. Portuguese men-of-war are violet snails’ main food.

When an animal can’t control its course, it’s tough for the sexes to get together. As a result, when a male violet snail senses a female in the area — they can’t see each other because violet snails have no eyes — he ejects sperm in her general direction. When the sperm hit their target, the female lays eggs and carries them with her beneath her bubble raft.

Eggs hatch into a drifting underwater form. When they mature, the tiny snails build their own bubble rafts and continue the nomadic existence.

I’ve often found violet snail shells on Hawaii’s windward beaches, and could fit about 10 in my palm. Here two barely fit. The snails might be different species, or the big ones might have grown large due to these nutrient-rich waters. On the same beach, I also found the biggest Portuguese man-of-war I’ve ever seen. Whatever their size, violet shells on any beach give me a fine marine animal fix. And I don’t even have to get wet.


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

©2015 Susan Scott