The Secret Life of Lobsters

by Trevor Corson

  That didn’t stop Mark from setting out to catch more lobsters than any Fernald in the history of Little Cranberry. By the age of twelve he was hauling five traps from a rowboat. He found a sixth trap washed up on the beach, which he dragged home, repaired, and carted down to the harbor in a wheelbarrow. He hung a bait bag full of herring inside, rowed a quarter mile from shore, tied a buoy onto the buoy line, and slid the trap overboard. As he watched it sink he wondered why the buoy and line had stayed aboard the boat, then realized he’d forgotten to tie the line to the trap. Mark went on to amass hundreds of traps and it was a mistake he would rarely repeat. He was always curious to see what his traps would haul up, and he frequently shifted his gear around to test different types of terrain. One year Mark built a trap the size of a small car just to see what it would catch. It was so big that to complete its construction Mark had to climb inside the trap himself.

  Dan was eager to pit his skills against the sea too, and by the age of seventeen was lobstering from an eighteen-foot boat. Bruce was still in the navy when Dan bought Pa’s Pride from Warren, in April of Dan’s senior year in high school. The evening he graduated, Dan went straight to bed so he could rise at 4:00 A.M. to haul his traps. Aboard Pa’s Pride Dan developed a lightning-fast hand. With only a few flicks of the wrist Dan could empty a trap, rebait it, and set it back over the side before the boat drifted off target. Hitting the sweet spots on the bottom was an art, and all the Fernald boys dreamed of matching the uncanny talent of a man named Lee Ham.

  When Lee Ham went lobstering it was almost as if he were making love to Mother Nature. Lee had a knack for planting his traps in the depressions in the seafloor, where lobsters liked to hide and hunt. He called these spots his honey holes. He caught the most lobsters of any of the Little Cranberry fishermen, and he made a profit on everyone else’s lobsters because he owned the dock where the fishermen sold their catch. Warren and his Fernald cousins sometimes traded their knowledge of the bottom, but Lee kept his honey holes to himself. It was said that he knew every pebble in the shallows around the island and every boulder offshore. Lee would steer his boat in among the rocks by the beach, propeller churning just above the stones, and set his gear so close to the lobsters’ hiding places that they had little choice but to enter his traps. He would steam far from land and drop his traps offshore with eerie precision, making rows of pit stops on the lobster highways of the deep.

  What the Fernald boys couldn’t match in their knowledge of honey holes, Mark made up for with sheer ambition and Dan with speed. Both prospered, and soon Dan needed a bigger boat. He’d heard about a new kind of material called fiberglass. In 1974, at the age of nineteen, Dan ordered a hull fashioned from the stuff and christened her Wind Song. She cost as much as a house.

  “What if something aboard her needs fixing?” one of the old-timers asked Dan. “Where the hell are you going to drive a nail in her if she’s made of plastic? You paid forty thousand dollars for a goddamn Clorox bottle.”

  Dan smiled because his boat would never need caulking, sanding, or painting. He kept hauling like lightning and sold Pa’s Pride to Bruce. Now Bruce needed a few honey holes of his own.

  Bruce had figured out the basics. Most adult lobsters around Little Cranberry Island spent the winter hunkered down twenty miles from shore, on the mud plains two hundred to three hundred feet underwater. It was so cold that they didn’t move around much, but they were warmer there than near shore, where winter’s bitter winds cooled the shallows quickly.

  Come spring, the sun warmed the surface of the sea and the lobsters set out toward land. At the edge of the mudflats they probed for the fingers of rocky ledge that rose toward the Cranberry Isles like mountain ridges rising from the desert. Between the ledges were silt-bottomed canyons that wound toward the islands. But with the surface waters warming, the lobsters mostly avoided the canyons and sought hard rock and altitude. When they hit the rocky slopes they clambered up toward ridges that would take them higher still, and closer to the realm of men.

  About five miles from Little Cranberry the lobsters cleared a lip of ledge and emerged onto a boulder-strewn plateau. After their steep ascent, they walked at a more relaxed pace, doing most of their moving at night and sheltering themselves in crevices by day. They’d risen to a depth of eighty or ninety feet, where the terrain, though flat, was littered with rocks that tested their ability to detour without straying off course. The lobsters paid little attention to the inhabitants they passed—sea urchins, starfish, snails, and sea cucumbers. Occasionally the lobsters hunted down one of these creatures for a meal on the road, but they were intent on covering ground. They seldom paused, even for the bait in a lobsterman’s trap. The warmth of the islands beckoned.

  The plateau ended abruptly. The lobsters crossed a trough of gravel and drew up against another steep rise. They gripped the craggy slope with their four pairs of legs and scrambled upward again, the water growing warmer as they drew closer to the sun. They were in the home stretch now—sixty feet deep, then fifty, then forty. The incline flattened and the lobsters began to sway with the swells rolling toward the beach. For the first time in months they basked in the heat of the shallows.

  Having mounted the rocky table that formed the Cranberry Isles, many of the lobsters made their way into a mile-wide cove surrounded on three sides by islands. If the lobsters had continued straight ahead, they would have emerged onto the gray cobble beach of Little Cranberry’s seaward shore and climbed into the grass and up into the woods. Bruce, in his sleep, sometimes saw them there, hordes marching up the hill. He dreamed of setting his traps in the island’s streambeds and in the drainage ditches along the road so he could catch them before they reached town.

  In reality the lobsters stopped and fanned out to find hiding places in the glacial debris underwater. Scurrying among the rocks, the lobsters sought the warmest nooks they could find, sometimes just fifteen or twenty feet below the crashing surf. The lobsters had good reason to secure hiding places. By now it was early summer, and in the warm water their shells had begun to loosen.

  A lobster’s shell gives the animal all of its rigidity. Under the shell, the lobster is little more than jelly-soft flesh and floppy organs. The problem with this arrangement is that the lobster is constantly growing, while its shell is fixed in size. To get bigger a lobster must literally burst its seams, escape its old shell, and expose its vulnerable inner self to the hungry world while it constructs a new shell large enough to allow its body to expand.

  The shell is composed of three layers. The outermost is a thin covering of proteins, lipids, and calcium salts. Underneath is a thicker matrix of proteins and the horny substance known as chitin, the same material that forms the exoskeletons of insects, as well as of arachnids like spiders and scorpions. The third layer is thicker still, and consists of a rigid, calcified outer portion that becomes softer toward the inner surface, like a suit of armor lined with padding. Underneath is a protective membrane, and finally the lobster’s delicate skin.

  If a lobster’s bodily functions went unregulated, the animal would be in a constant state of shedding its shell and growing a new one. Such exhibitionism would make normal life impossible, so lobsters have glands inside the stalks of their eyes that release a hormone that inhibits molting. A combination of cues, including warming temperatures and longer days, constrains the production of the hormone and releases steroids that begin the molt cycle. Proof of the hormone’s importance can easily be obtained, though the experiment is somewhat sadistic: cutting off the lobster’s eyes induces the animal to shed its shell almost immediately.

  In the weeks prior to molting, the lobster’s skin cells enlarge and secrete the beginnings of an entirely new shell underneath the old one. Meanwhile, calcium drains out of the old shell and accumulates in a pair of bulbous reservoirs on either side of the stomach called gastroliths, to be recycled later.

  When the lobster is ready to shed, it pumps in seawater and distributes it through its body, c
ausing hydrostatic pressure to force the old shell away from the new one. The lobster remains mobile and active until the last minute, when the membrane that lines its old shell bursts and the animal falls over on its side, helpless and immobilized. After twenty minutes or so, the lobster’s back detaches and the animal pulls its antennae, mouthparts, legs, and claws out of their former coverings, aided by a lubricating fluid. The most difficult moment comes when the lobster tugs its claw muscles out through the slender upper segments that form its wrists. Before molting the animal must diet away half the mass in its claws or risk getting stuck in its old clothes. Worse, because a lobster is an invertebrate, every anatomic feature that is rigid is part of the exoskeleton, including the teeth inside the stomach that grind food. The lobster must rip out the lining of its throat, stomach, and anus before it is free of the old shell. Some die trying.

  When the lining of the stomach comes out, the gastroliths, containing the calcium reserves, are released. The lobster immediately digests the gastroliths to recycle some of the rigidity of its old shell. Centuries ago, gastroliths from lobsters and crayfish were commonly ingested by humans as medicine. In the 1700s, apothecary shops throughout the Russian Empire sold the little white balls to dissolve kidney stones, heal eye inflammation, and cure epilepsy. Gastroliths were collected from crayfish by catching thousands of the animals in the summertime, dumping them into pits, crushing them, and letting them decompose over the winter—the stench was said to be horrendous. In the spring the mess was washed down and the gastroliths sorted out with sieves. Demand for the medicine was so strong that fakes, formed from chalk, were common. For a molting lobster the gastroliths have a specific function. Their calcium bypasses most of the new shell and goes directly to harden the tips of the legs and the cutting edges of the mouthparts—the appendages critical for feeding.

  Flexing the muscles of its abdomen, the lobster shakes off the old shell around its tail and is free. Again the lobster pumps itself full of water and expands, rapidly outstripping its former size. Soon it is able to stand, and its first priority is to use its newly rigid mouthparts to devour the husk of its former self, a convenient and nutritious source of additional calcium. What the lobster doesn’t finish of its old shell it buries, perhaps to hide evidence of its weakness.

  The minerals and nutrients the lobster absorbs are secreted throughout the new shell, which over the next few days thickens enough to allow the flesh underneath to shrink back to its actual size, making space for future growth.

  The lobster has gained 15 percent in body length and 50 percent in volume. In the first five years of life lobsters undergo this hazardous routine about twenty-five times. In adolescence the rate decreases to about twice a year. Lobsters that have reached adulthood molt once a year on average, and increasingly seldom as they grow larger. Exactly how often, though, is difficult to calculate, because determining the age of a wild lobster has so far proved impossible. A fish contains a chronological record of its life in its otolith, a bone inside the brain cavity that grows in concentric layers like the rings of a tree. But lobsters are invertebrates. They toss their exoskeletons off with such maddening thoroughness that all trace of their age is erased.

  Bruce once saw a lobster molt aboard his boat. The lobster had mistaken a trap for a sanctuary and let its shell loosen, only to be hauled up after it was too late. Bruce slid the lobster into a bucket of seawater and watched its shell open. With heroic patience and some spasmodic flailing the lobster extracted itself and emerged wrinkled and soft as Jell-O. But by the end of the day it had restored its shape and grown larger. Coating its skin was a crinkly shell the consistency of cling wrap.

  With the arrival of molting season Bruce learned to plaster the shoreline with his gear, steering his boat as close to the rocks as he dared and tucking his traps between boulders near the surf. A week or two after shedding, the lobsters’ big new shells were strong enough to allow them to emerge. As hunger overcame them, they were lured from their hollows by the lobstermen’s bait, and by midsummer the waters around the island teemed with new “shedders” that met the minimum legal size for capture in the state of Maine. They entered the traps in droves, and their meat tasted especially sweet.

  When the lobsters came out of hiding Bruce hauled like a madman. But he also learned that he couldn’t afford to keep all his gear in the shallows. Within days the shedders were combining their hunt for food with another imperative—the return to deeper water. Soon other lobsters, hiding farther from the islands, would shed and emerge too. The wave of molting would progress offshore through the autumn, often lasting until December, and the trick for a lobsterman wasn’t so much to follow the lobsters as to anticipate where among the rocky boulevards and muddy valleys the animals were going to be. If the traps weren’t already in place when the lobsters passed through, a fisherman had missed his chance.

  Bruce knew that to pay off Pa’s Pride he would have to test new locations on the bottom. Eyes glued to the Fathometer, he had run the boat due east, and after a mile the stylus had dropped. He’d circled, then run south and circled again. If he’d read the burn line on the Fathometer’s roll of paper right, he’d found a muddy canyon 150 feet deep, heading straight out to sea. Bruce had set a string of traps just beyond the drop-off.

  Now, a week later, he was hauling those traps back up. The first one broke the surface and Bruce shut off the hauler. He grasped the rope bridle to tug the trap onto the rail, but it was too heavy. Grabbing it with both hands, he seesawed it out of the water and saw that the trap was oozing a pungent brown goo.

  “Congratulations,” Bruce muttered through gritted teeth, “you’ve hauled up a load of stinking mud.”

  He wrestled the trap aboard and wiped the mud off in gobs, smearing his rubber overalls and the deck with slime. He leaned over and peered between the wooden slats of the trap. Inside was a glistening pile of shedders.

  PART TWO

  Mating

  3

  Scent of a Woman

  At the age of twenty-five Jelle Atema had left the Netherlands on a plane bound for America. He had athletic good looks and a promising international career, and was a gifted flute player—a student of the French master Jean-Pierre Rampal. In high school Jelle’s goal had been to sculpt himself into a Renaissance man. If he had known that in the United States his obsession would become the sex life of the American lobster, would he ever have left Europe?

  Four years later it was best, Jelle supposed, not to dwell on such questions. He chuckled, dropped a chunk of fish into each lobster’s tank, and surveyed his charges—half of them male and the other half female. Within moments the lobsters flicked their antennae at the scent of prey and began waving their feeding mandibles. In a few seconds his lobsters were gnawing on their food. It was astonishing to Jelle how fast the American lobster worked.

  Each lobster lived in a thirty-gallon Plexiglas tank with flowing seawater. Jelle had spent the past several days setting up cameras and lights next to the tanks and fine-tuning his behavioral coding system for male-female interaction. All that remained was for one of the females to get undressed.

  The basic reproductive cycle of the American lobster begins when the female sheds her old shell. This arrangement gives the female time between molts to mate, lay her eggs, and carry the eggs until they hatch before she sheds her shell again—a schedule made necessary by the fact that the eggs are attached to the shell and would be lost during a shed. Jelle had heard reports of American lobsters copulating even when the female’s shell was hard, but most female lobsters seemed to mate when their bodies were soft, immediately after molting. Jelle’s first female to get lucky would be the one that molted first. It was June and they were all on the verge of shedding.

  As a graduate student in the Netherlands Jelle had studied how a species of small shark detected vibrations and electric fields in the water. While finishing his Ph.D. in 1966 Jelle had been invited to join a group of scientists at the University of Michigan who were
studying how fish sensed chemicals. In Ann Arbor Jelle became entranced with the catfish, and how it used smell and taste. Underwater, smell and taste are, in a sense, simply two aspects of the same thing—the detection of molecules in water. The difference has to do with the organs employed and the purposes to which detection is put. Jelle’s catfish used their sense of smell to socialize and select mates, identifying one another as individuals by means of unique odor signatures. They used taste to search for food, licking the water, as it were, to find dead flesh.

  Jelle’s research on the subject was getting under way when the prestigious Woods Hole Oceanographic Institution in Massachusetts offered to build him a seawater laboratory on Cape Cod. It was an offer he couldn’t refuse, especially when Jelle learned that the institution wanted him to head up an ambitious new program: the study of chemical communication in the sea. There was growing concern over the possible effects of oil pollution on marine populations. It was thought that molecules from petroleum products could interfere with both smell and taste, upsetting the ability of organisms to feed, socialize, and reproduce.

  Jelle moved to Cape Cod in February of 1970. The first question was what organism to study. He needed a creature that was easy to acquire, handle, and manipulate and that had accessible organs of smell and taste. An animal to which electronic devices could be attached would be useful. And Jelle himself had a discriminating sense of taste. A high level of postexperimental edibility would be a bonus.