Barnacles melt in your mouth, not on your ship
Pacific Grove, Calif. — American taxpayers spend millions each year to eliminate the stubborn little critters, while in Portugal, they're considered a delicacy. In Egypt, they're indirectly responsible for fouling the waters of the Suez Canal. And in Virginia's Norfolk Harbor, they're stuck to a boat named the Sea Mule which has a teflon-like coating.
Barnacles, crusty shellfish which attach themselves to buoys, rocks, boats, and fish, have been the objects of academic inquiry since Charles Darwin's monograph in 1851. But today, most research into their discrete life has one end in sight - avoiding them.
And for good reason: Research chemist John Bultman of the Navy Research Laboratory in Washington, D.C., estimates that it costs well over $10 million each year to rid the Navy's ships of barnacle blight.
Heavy barnacle crusts can slow a ship down to half speed and result in delayed voyages, high fuel consumption, excessive wear and tear on the ship, and expensive lay-ups in dry dock.
One of scientists' traditional solutions has been antifouling coatings that keep barnacles off boat hulls by gradually leaching chemicals into the water. But, according to James Griffith of the Navy Research Laboratory, such methods have serious drawbacks. Egypt, for example, has found that copper antifouling paints have been polluting the Suez Canal.
To solve this dilemma, Dr. Griffith's research group has been working since 1968 to design a coating that keeps barnacles from sticking to boats in the first place. Since 1975, the Sea Mule has been coated with just such a experimental substance. ''Barnacles can still get a hold,'' said Griffith, ''but they are easy to take off.''
Barnacles are crustaceans, distant cousins to crab and shrimp. They spend their first few weeks of life floating through the water, looking for a home. The lucky ones stick to an obliging surface with adhesive disks on the ends of the antennae on their heads. The less fortunate ones end up as breakfast for other sea life. Barnacles are at the mercy of waves when finding a place to settle. How many actually survive, where the survivors come from, and how they attach themselves are unknown.
Scientists like Dr. Griffith have focused on finding a protective coating for the boats themselves. However, Mark Denny, a young professor at Stanford University's Hopkins Marine Station in Pacific Grove, Calif., now is turning the barnacle problem on its head and exploring it from a different angle.
''The Navy has spent a lot of money looking at barnacle cement - how to get rid of it,'' says Mr. Denny, a tall, bearded fellow in loose blue jeans and Birkenstock sandals. Denny is planting a television camera underwater in a Monterey intertidal area, not far from the fabled Cannery Row, to study what makes barnacles stick. Only then, he says, can we learn how to unstick them.
Denny has applied to the Office of Naval Research for a $50,000 grant to investigate the epoxy-like cement that binds barnacles to boats. According to Denny, barnacles, to secure themselves, must withstand waves that crash at velocities ''well above hurricane winds'' every 15 to 20 seconds.
In spite of it all, they stand firm for decades. In the late '20s, biologist Ed Ricketts (immortalized as John Steinbeck's ''Doc'' in the novel ''Cannery Row'') tagged some barnacles under Monterrey wharf. Some are still alive. Once barnacles find a home, they are stuck for life, says Denny. They begin the ongoing process of building tent-like shells and spend the rest of their lives standing on their heads and eating with their feet, which trap plankton as it rushes by.
Barnacles who like life ''in the fast lane'' choose mobile homes: whales, marlins, andboats. Such hitchhikers take advantage of currents created by their fast-moving hosts for easy access to foodstuff.
In spite of the mischief they create, barnacles pay their ecological dues, Denny says. As filter-feeders (marine animals that capture tiny particles in the water), they are part of an elaborate intertidal ''water-conditioning'' service. They also become meals for snails, starfish, and birds.
And humans, too. In Portugal, Denny says, meat from the fleshy stalk of the gooseneck barnacle is considered a gourmet treat. It tastes like lobster and costs between $15 and $20 a pound. The problem? It takes several hundred to make a meal.