Honolulu Star-Advertiser © Susan Scott
June 8, 2007
While driving my sailboat recently, I noticed it didn’t go as fast as it should. I called the man who rebuilt the engine.
“Was the boat sitting awhile?” he asked.
“Yes.”
“Check the prop,” he said. “If it’s fouled, it’ll slow the boat a lot.”
OK. But do we have to use the term fouled? Just because marine animals set up housekeeping on my boat doesn’t make them villains. Rather than foulers, I prefer to think of these industrious little creatures as pioneers.
So under the boat I swam to check for pioneers, and, oh dear, had they been busy. The propeller was covered with barnacles.
The rudder and hull, however, were mostly bare due to the antipioneer paint I’d applied in Tahiti. This special boat-bottom paint contains copper, a metal colonizers that don’t like. The bottom of my keel was another story.
While crossing the South Pacific, I’d plowed through the sand enough times to scrape off its paint, and the barnacles down there were having an open house.
Barnacles are one of the animals that really slow a boat’s progress, but they aren’t the first creatures to stick to an unprotected item placed in the ocean. There’s order to this.
If you place an unpainted object in still, warm water, naturally occurring marine bacteria will start hanging onto it within the hour. In harbors with organic pollution, this so-called slime layer builds up faster.
The slime layer attracts single-celled animals, called protozoa, that eat bacteria. If the object is in shallow water single-celled algae, which need light to photosynthesize, will also stick to the surface.
To passing larvae looking for a home, such a collection of plants and animals must look like a welcome wagon. But even so, not all larvae drop in.
The first species that gets there usually dominates the community due to a phenomenon called the founder effect. This occurs when founders send out chemical signals that passing members of their species recognize. It’s like the founders are calling out, “Hey, the camp is over here!”
Founders can be sponges, hydroids, tubeworms, shrimplike animals called amphipods, sea squirts, corals and shelled animals like the sailor’s old nemesis, barnacles.
In the tropics, an unprotected surface can have pretty heavy growth in as little as 30 days. Wood goes faster than plastics, glass and metals because it has a rougher surface, and therefore, more places for the animals to hang on.
If you leave this mass of microscopic newcomers lounging on your hull long enough, a third group will come to feed on and hide among them. These can be crabs, sea spiders, brittle stars, bivalves and even fish. When the blennies and gobies move in, you know it’s time to bust up the party.
I donned my scuba gear and jumped off the back of the boat, scraping tools in hand. It pains me to kill all those marine animals just because they picked my prop for a home. But life’s tough in the ocean, and after appreciating their beauty and apologizing, I scraped.
And a wonderful thing happened. As the pioneers dropped from the prop, a school of cardinalfish moved in beneath me to eat the fallen.
That improved my mood.