Where The Wild Things Are
I had volunteered to help my friend Jim clean the bottom of his dinghy. The day before, as we rowed out to his mooring, a green mane — a summer's worth of marine concupiscence — had trailed after us. Now, with the hull upside down on the dock, what had started as a chore turned into a treasure hunt.
A boat's bottom is teeming with life that, to the uninitiated, rivals a rain forest in its wondrous qualities. That is, if the boat has not been treated with an anti-fouling paint like tributyltin, or TBT.TBT causes, among other things, imposex! That's the superimposition of male sex characteristics on females, and it is not something you want if you are a gastropod like a snail or a whelk. My friend would never do such a thing to a snail, hence this water wonderland.
Our first surprise was color. The seaweed grass skirt we had blamed for our arduous progress across the harbor turned out to be but a submarine forest canopy. The dense understory was much livelier, a Jackson Pollock of red and yellow and purple splotches. The lumps of Jell-O that made it such a vivid ensemble were sea squirts — or tunicates to give them their more official title. That much I knew. The individual animals are less than a quarter inch long, but these gooey colonies were made up of thousands of them. Of what kind, and indeed how many kinds we were looking at, I had no idea.
The purple one that looked like a nest of Phillips head screws — Rachel Carson called it a "spangled mat" — was surely the golden star tunicate. The yellowish mass whose fingers flopped everywhere looked perilously like one of the dread Didemnum species. Neither belongs on our boat bottoms — or ocean bottoms, either. Invasive stowaways, they are overgrowing those species that do belong. Didemnum is smothering all before it across some ninety square miles — and growing — of prime fish habitat on George's Bank. Having discovered it only two years ago, marine biologists have so far been able to do little but stand back and watch in dismay.
Peeling away a mess of muddy tubes unearthed a sea grape, another tunicate, but this one a loner. Its two siphons — one for sucking the water in and over a filter, the other for pumping it out — clamped shut at the shock like nervous sea anemones, but they reopened gratifyingly quickly. No cigar for guessing where this one got its moniker: it looked just like a colorless, skinless grape.
The second surprise uncovering this underwater wilderness was movement. When we first flipped the boat over, the joint was jumping with tiny shrimp-like things. They were obviously of the same ilk as beach fleas, little arced amphipods with lots of legs. But they were crawling, too. Around the miniature clams and mussels that clung to the fiberglass, a small rag worm ranged in an endless wave of graceful undulations that melded beauty and the beast into a single shiver-worthy apparition. Rag worms can grow to over half a foot in length and are highly prized for bait. Pound for pound, this lowly creature is, at twenty-five dollars, the most valuable species in Maine's fishery. In fact, Maine boasts the first marine worm farm — a British firm — in the United States.
But not everything was so easily identified as the rag worm and the shrimpy things. Dozens of sinister, articulated feelers were emerging from all over the mess, probing their surroundings with long fingers that narrowed into sting-like points. Ranging in size from half to a couple of inches, some were pink, some clear. They looked like nothing so much as praying mantises not assembled quite right, mantises with the predatory air of the tripods in War of the Worlds.
What were they? Stupidly — for an inveterate bird-watcher who finds in the thrill of nature identification one of life's joys — I had neglected to bring a field guide with me. So for future reference when I should have access to a text, I pulled out my magnifying glass for a closer look.
As much as it was aquatic, the world became bizarrely interstellar. Barely visible before, copepods jetted in and out of focus like little spaceships. They looked insignificant, but copepods are a vital link in the food chain. Termed grazers, they "graze" on the microscopic phytoplankton that is the source of life in the sea, preparing themselves, as it were, for their role in our own food pyramid. Copepods are the chief source of nourishment for young herring. I can almost taste them in my kippers.
Amid some kelp, a clump of hydroids appeared, pale pink stems less than an inch long that ended in an almost crimson flower. Actually, hydroids are animals, not plants; the "flower" is a wreath of tentacles armed with spring-loaded little harpoons called cnidocils, with which they catch their prey. The principle is the same as with the stinger of a jellyfish, just on a smaller (and, to us, less painful) scale.
As soon as we finished scraping these and many other fascinating finds off the bottom of Jim's boat, I couldn't wait to get home and check them out in a book. I am not a marine biologist, and I had no idea where to look. Were the War of the Worlds tripods larval forms of something else? Where to start? Armed with little more than curiosity, I made respectable inroads, thanks to the Peterson Field Guides.
The key in the end papers gave me the clue I was looking for. The tripods were skeleton shrimps, and when I got to the appropriate page, it was all there: "Unlike any other amphipod"; "suggest miniature praying mantises"; "slow and methodical." And finally, "These peculiar little amphipods are often abundant among bushy hydroids, bryozoans, fine weeds, and other fouling organisms on rocks, pilings, and buoys."
Despite my ignorance, this identification of something completely unknown to me had not been particularly difficult, but it made my universe expand with a rare satisfaction. The satisfaction felt when looking up a "life bird" and having positively identified it.
And all I had to do was look under a boat.