Monthly Archives: March 2015

Large salps on West Coast get their name from a Titan

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

A dead salp found on Dungeness Spit in Washington state. ©2015 Susan Scott

While visiting Washington state recently, my friends took me hiking on Dungeness Spit, a National Wildlife Refuge poking 5.5 miles into the Pacific Ocean’s Strait of Juan de Fuca. I saw several marine birds new to me, and fantastic snowcapped mountains. But what thrilled me most was a dead thing we found on the beach.

The creature was a clear, firm gelatinous pouch about 6 inches long with red-and-yellow innards and two appendages. We had no idea what it was. Then last week my fellow hiker, Mary, emailed me Fierro Marine Center’s newsletter. Others in the area had been finding the same creatures and, like us, wondered what they were.

The animal, the center reports, is a salp.

Several years ago I wrote about half-inch-long salps that I found off Puerto Vallarta, Mexico, but they looked nothing like this one. (see picutre below) But in my reading back then, I had missed a key point: Some salps are huge. The species washing up in Washington and elsewhere on the West Coast grow to 10 inches long, the largest of all salps.

The scientific name for this salp is Thetys vagina, named by German naturalist Wilhelm Gottlieb Tilesius von Tilenau (1769-1857). He studied marine biology in Portugal, where he found and named the giant salp.

(In Greek mythology, Thetys was a Titan, and although today the species name gives pause, in 1802 the Latin word “vagina” meant “sheath” and was not yet used in an anatomical sense.)

Salps are drifting barrel-shaped animals that eat their fellow planktonic creatures by sucking water in one end and pushing it out the other. Bands of muscles around the bodies give the creatures their rubbery quality.

At one stage of its life, a salp clones itself into a chain. Thetys vagina chains can contain hundreds of individuals and be several yards long. Single bodies eventually break away and clone their own chain.

salp
Thetys Vagina, Dungeness Spit, Washington State

Thetys vagina isn’t usually seen in Washington, and no one knows why it’s showing up there and on other West Coast shores. Because salps are boom-or-bust organisms that travel with currents and thrive with plankton blooms (and then die off), the occurrence may be natural.

Check out the Thetys vagina in action at Vimeo video..

You would think that after 30-some years of exploring the oceans, I might have been able to identify the Dungeness Spit creature as a salp. But that’s the fun of marine biology. When it comes to sizes, shapes and attention-grabbing names, you never know what you’ll find.

Tiny Salp, Sea of Cortez


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

©2015 Susan Scott

 

Fresh water rife with life but lacks seas’ buoyancy

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

One of the biggest pains about the ocean is salt. It corrodes the wheels on my sliding doors, rusts my boat’s so-called stainless steel and makes my hair stiff and skin itch. But after spending the last two weeks in Bangladesh and Thailand’s interior, salt was one of the things I missed most.

Bangladesh is a country of fresh water. Most land there is silt deposited by 15,000 miles of 700 or so rivers, creating some of the world’s most fertile plains.

Bangladesh bridge

All this fresh water flowing next to productive land is an agricultural gold mine. Brilliant green rice paddies, edged with blossoming mango trees and decorative flower beds, caused our team of five volunteers to speak often about the beauty of rural Bangladesh.

The country’s well-named flood plains, however, are also a curse. Cyclones, monsoons and Himalayan spring melt often cause overflows, resulting in devastating losses of lives, homes and livestock.

Even with all this water, I found no place to swim. River recreation is uncommon in Bangladesh.

river

The bamboo huts of Thailand’s Khao Sok National Park

I swam to my heart’s content, though, in Thailand’s Khao Sok National Park, where we stopped on our way home for a few days’ R & R.

The rainforest park hosts limestone cliffs and dense jungle around a 102-square-mile reservoir created by the damming of the Klong Saeng River in 1980. The park is famous for terrestrial wildlife and shoreside bungalows floating on bamboo rafts. I had only to step off my lanai to plunge into clear, warm water.

And then I sank. Not to the bottom, because I know how to swim. But my lack of buoyancy in fresh water compared with my usual ocean dips surprised me.

The difference between lake and ocean buoyancy comes from salt. The ocean is about 3 percent salt, meaning that in 100 pounds of seawater (12 gallons), 3 pounds is salt. If you took all the salt out of the ocean and layered it evenly over Earth’s land, it would measure 500 feet high. (Picture a 50-story office building.)

It’s the added weight of salt in seawater that causes it to lift us higher than fresh water. Buoyancy force (the water pushing up) is the weight of the water displaced, or pushed aside, when we get in. Because salt water is heavier than fresh, we float with less effort.

And even though fresh water hosts nearly as many fish species as salt water (about 15,000 in each), those in rivers and lakes aren’t as concentrated or visible as those on coral reefs.

monkey

Native long-tailed macaque monkeys that inhabit the rainforest around the lake are visible from kayaks.

I enjoyed my visit to Bangladesh and Thailand, but even when surrounded by radiant rice paddies, whistling monkeys and brilliant birds, I missed my marine animals. I’m happy to be home and salty.


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

©2015 Susan Scott

 

Vultures’ immune systems let them scarf down carrion

Published March 2, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott

vulture

During my recent visit to the Portland Audubon House in Oregon, I fell in love with a turkey vulture named Ruby.

This wasn’t the first time the species captured my heart.

While sailing in the Gulf of Cali­for­nia from 2008 to 2013, I learned to pay attention to the big black birds with bald red heads. Their soaring and cactus-top perching often led me to wildlife spectacles I would otherwise have missed.

vulture

For example, I once followed a flock of circling vultures to a secluded beach and found them eating a huge, freshly dead sea turtle, intact except for a missing head. Seeing the birds poking their featherless heads deep into the neck hole was at first disconcerting, but soon I viewed it as recycling at its most natural.

Most people think of turkey vultures as harbingers of death and disease, but it’s just the opposite. The species never attacks live prey, and by eating the tissue of dead animals, vultures prevent disease.

These scavengers have tough immune systems that fight off botulism, anthrax, salmonella and cholera.

Some religious groups revere vultures, believing the birds release souls from bodies. Tibetan Buddhists have “sky burials” where vultures eat the dead, and Zoroastrians offer their dead to the birds on a raised platform.

Turkey vultures

The turkey vulture’s scientific name, Cathartes aura, fits such veneration. The words mean “golden purifier” or “purifying breeze.”

The turkey vulture get its name from the head’s resemblance to that of a turkey, but the two species aren’t related. In the U.S. people often call vultures buzzards, but “buzzard” is part of the common name of several hawks in Europe.

The turkey vulture has a keen sense of smell, so sensitive that vultures avoid piercing the scent gland when eating skunks.

As to the turkey vulture named Ruby, someone stole her as a chick in 2007. After about six months Ruby escaped her abductor and had the good fortune to fly to an Oregon farm where she followed the owner around and landed on her arm.

The woman called the Audubon Society of Portland, and they gave Ruby a safe and loving home at their Wildlife Care Center.

Workers there (wearing leather shields to protect their arms from Ruby’s sharp claws) frequently bring the bird out to the public. She needs social time, a volunteer explained, with members of what she now considers her own species: people.

Portland has an outstanding Audubon center, five minutes from downtown. For a memorable experience, stop in and say hello to a friendly vulture named Ruby.

vulture


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

©2015 Susan Scott