Monthly Archives: August 2016

Nonprofit’s scientific news is a salve for a gloomy world

Published August 27, 2016 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2016 Susan Scott

The Society for Science and the Public, a nonprofit organization dedicated to sharing scientific news, emails me with weekly updates. As I scroll through the headlines, I’m amazed at the scope of human curiosity and people’s creativity in gaining knowledge, from finding exoplanets to editing genes.

I can spend hours at this well-written site, but before I lose myself in the DNA of Darwin’s dogs or how neuroscientists view “Donkey Kong,” I check out the latest in the marine world. One study that caught my attention was about the Taser-packing fish, the electric eel.

Before I even read the study, I wondered how this eel, scientific name Electrophorus electricus, is related to the moray eels we know so well here in Hawaii.

They’re not. The electric eel isn’t an eel at all. It’s a member of a fish family called knifefish, native to South American lakes and rivers.

The 6-foot-long electric eel delivers up to 600 volts to kill its prey. For those of us who’ve been accidentally shocked by a 110-volt household outlet — or worse, the 220 volts used in other countries — 600 volts is a mind-blowing jolt. Evolution made sure that the eel got its meal.

In waters where electric eels go hunting, other fish lie low, staying motionless behind rocks and among plants. Given such hiding, plus the fact that the electric eel’s vision is poor and the rivers are murky, a biologist at Nashville’s Vanderbilt University wondered how the eel finds its prey.

The researcher discovered that as the eel swims it shoots out tiny electric currents that cause a hiding fish’s muscles to twitch. And that’s all it takes. The eel heads toward the twitcher, shocks and eats.

Another fishy headline read, “Female fish have a fail-safe for surprise sperm attacks.” After a female ocellated wrasse (a Mediterranean species) chooses a mate, the couple make their nest. But bachelor wrasses lurk nearby, waiting for the female to lay her eggs. The rascal then dashes in and floods them with sperm. A Yale biologist discovered, however, that the female wrasse’s ovaries coat the eggs with a fluid that favors fast-swimming sperm. Because mated males have speedier sperm, the female’s chosen mate wins the race to the egg.

Sometimes I get so discouraged by the stream of terrible news throughout the world that I wonder whether our species is doomed. But then I get these science emails and life looks much better. T.H. White explained my feeling in a favorite book, “The Once and Future King”:

“‘The best thing for being sad,’ replied Merlin … ‘is to learn something. … Learn why the world wags and what wags it. That is the only thing which the mind can never exhaust, never alienate, never be tortured by, never fear or distrust, and never dream of regretting.’”

For a learning lift, visit www.societyforscience.org.

Little cleaner wrasses offer spa experience to other fish

Published August 20, 2016 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2016 Susan Scott
A cleaner wrass with an island jack customer. ©2016 Susan Scott

A cleaner wrass with an island jack customer. ©2016 Susan Scott

Last week, in about 7 feet of water, I swam over a reef wall and found myself in the middle of a dozen jacks, a new species to me, each bearing yellow, dashiki marks on their sides.

Having a monster in their midst caused the fish to dart up, down and around, but surprisingly they didn’t flee. When I backed off, I saw why. The jacks were waiting for a turn at the spa.

Reef spas are run by narrow, 4-inch-long fish called cleaner wrasses. A variety of fish pick goodies off other fish for food, but only the cleaner wrasse sets up a service station. It’s a one-stop shop for pest removal, wound debridement and massage.

The wrasses work alone, in pairs or in teams up to five. To advertise their business, the little fish bob their neonlike bodies up and down. The front half of the fish’s body is a glowing yellow, and the rear half is purple with lavender edges. A black stripe runs from eye to tail, accentuating the fish’s bright colors.

You can’t tell a male from a female cleaner wrasse by color, but you can tell a juvenile from an adult because young cleaners are nearly all black. The kids get their grown-up colors early on, when they’re only about an inch and a half long. If a cranky adult chases away a little wrasse sporting its new colors, the youngster can change back to black and safely move to a friendlier neighborhood.

When I first learned about cleaner wrasses while studying biology at the University of Hawaii, the fact that Hawaii hosts an endemic species was so emphasized that I thought the little service fish was a Hawaii-only phenomenon. Later, though, I saw similar cleaner wrasses on just about every reef I visited in the tropical Pacific. The Hawaiian cleaner wrasse, it turns out, is only one of five species in the Indian and Pacific oceans. Ours, though, is the prettiest.

Not all fish that visit wrasse cleaning stations have parasites or dead skin that’s bugging them. Researchers believe that the sensation of the wrasses’ fins wiggling against the skin feels good to their clients. Big fish sometimes come just for a back rub.

The jacks I saw lining up for a rubdown are a rather rare species here. Called island jacks, yellowspot trevally or ulua, these silvery fish with yellow side spots usually school in deep water but sometimes come inshore. They grow to about 28 inches.

I’d never before seen a school of island jacks or watched any jack hold perfectly still with mouth and gill covers open while a cleaner wrasse worked it over. That’s why I don’t mind snorkeling in the same seemingly unremarkable places over and over. I never know what I’m going to get, and it’s always an adventure.

Lone sea pen makes mark during shallow-water swim

Published August 13, 2015 in the “Ocean Watch” column,
Honolulu Star-Advertiser ©2016 Susan Scott
A sea pen is found in Australia’s Great Barrier Reef Marine Park. ©2016 Susan Scott

A sea pen is found in Australia’s Great Barrier Reef Marine Park. ©2016 Susan Scott

Craig and I don’t often snorkel side by side. He thinks that swimming fast in deep water is best, because that’s where the big jacks, sharks and manta rays hang out. I, however, like to float quietly in a few feet of water. Not only do some astonishing creatures live there, but I get to see them up close and take their pictures.

During a recent swim off a tiny island in Australia’s Great Barrier Reef Marine Park, Craig, as usual, headed out and I headed in. And sure enough, confirming my theory that shallow is good, there stood, like a lone sentry, the biggest, most beautiful sea pen I’ve ever seen.

I’ve not seen many — this discovery was No. 3. Sea pens belong to the soft coral clan and aren’t particularly rare, living from shallow water to deep. But the animals like to set up housekeeping in calm water and that usually means deep. Down around 150 feet, one researcher in Puget Sound found an average of 23 sea pens per square yard for miles on end.

Several sea pen species range from tropical to temperate waters around the world, growing 6 inches to 2 feet. One species in Scotland grows to 6 feet tall. Its witty name: the tall sea pen.

Sea pens were so named because the upper parts of their bodies look like the fluffy feather quills people once used for writing. The animal’s bottoms, however, look like tulip bulbs buried in sand or mud.

From the bulbous base, a central stalk rises with delicate branches extending from each side like a feather. The branches bear hundreds to thousands of tiny mouths, each surrounded by eight tentacles (that’s the octo in octocorals, the scientific name for soft corals).

The sea pen orients itself into gentle currents with its branches stretched out. Unlucky plankton animals that drift through the branches get stung and eaten.

On the sides of the sea pen’s central stalk are holes lined with beating hairs, some drawing water in and others pushing it out through countless channels. Muscle contractions of the body also assist with this circulation system.

It would seem that these delicate feathery animals are rooted to their spots, but no. If disturbed, a sea pen can pull up its orbed anchor, inflate its body with water and drift like a balloon in the current to a new home.

Vast plains of fleshy, slow-moving animals are easy targets for carnivores. Nudibranchs (snails without shells) eat small sea pens. Starfish target adults.

I couldn’t resist lightly touching my 6-inch-tall pen, and that was that. A sea pen’s defense is to exhale its water and sink into the sand.

When Craig and I reunited, he told me he had seen a shark. Big deal. I had made an Australian pen pal.

Kolea kamaaina at heart, plover lovers sure to agree

Published August 6, 2016 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2016 Susan Scott
Kolea

A kolea nest holds two chicks and two eggs in Alaska. The birds fly 3,000 miles to Hawaii to spend nearly nine months of the year. Courtesy O.W. Johnson ©June 2016

I’ve always wondered where home was for kolea. Is it Alaska, where for about three months the Pacific golden plovers build nests, raise chicks and “forget” their winter partnerships with humans? (In kolea nesting grounds, the birds behave as if people are predators.)

Or is home in Hawaii where these migratory shorebirds spend nearly nine months of the year living in harmony with humans? I’m sure kolea fans in Hawaii share my bias: Home is here.

Reader Bert Weeks of Aiea emailed that he saw two female plovers foraging in his neighbor’s yard July 25. On the same day another reader, Ann Egleston, saw Pacific golden plovers at the Diamond Head cemetery. By the 29th several kolea were gracing the lawns of Kapiolani Community College and the Department of Defense.

Because it takes plovers four days (nonstop) to fly here, these birds had to leave Alaska July 21. Such early returnees are probably adults that couldn’t find a mate this year, or parents that lost their brood to predators or bad weather.

Most adult kolea that successfully raised chicks arrive in Hawaii in August. Females come first, then males. After their parents leave, kolea chicks stick around the tundra for as long as the weather holds, fueling up for their 3,000-mile migration. First-year kolea navigate to Hawaii alone, on instinct, arriving in September, October and as late as November.

Only about 20 percent of each summer’s offspring live through their first year. If they make the journey, youngsters in Hawaii must then compete with stronger, experienced adults for foraging territory.

People worldwide take great pleasure in feeding wild birds, a practice endorsed by the Cornell Lab of Ornithology, the Humane Society of the United States, Birdlife International, the Royal Society for the Protection of Birds and other conservation organizations. Not all experts agree on whether backyard feeding helps bird populations overall, but they do agree that feeding can help individual birds in a neighborhood.

Feeding also connects people with nature, often profoundly, turning observers into keen citizen scientists. If you decide to feed your plover, offer it healthy food such as mealworms or bits of cooked egg. My kolea likes her eggs scrambled. Last year I learned to outsmart grabby mynahs and pushy bulbuls by luring them with a little something around a blind corner of the house. My plover caught on quickly.

When the others flew off for breadcrumbs, she stayed with me and ate her bits of egg in peace. She’s not back yet, but when she arrives I’ll drape a verbal flower lei around her neck by calling out, “Aloha, my friend! Welcome home.”