Article

Captain Leon Rose - Horseshoe Crab Trawler

By Patrick J. Hendrickson

The Atlantic swell greets us as we round the Assateague Hook, down the channel bordered by slowly blinking red and green lights which extend and converge into darkness. The smells of land give way to a humid, musky aroma that originates from that vast offshore current, the Gulf Stream. Heat lightning illuminates the western horizon, heralding the approach of a distant cold front that will break the heat of this muggy August night. The diesel engine taps out a sewing machine-rhythm, as I take in the sights and sounds of the boat in an environment totally foreign to my senses. With no real horizon to reference movement to my brain, the rolling and pitching of the deck have me dancing an erratic solo Tango, much to the amusement of the salty deckhands. I retreat indoors.

Captain Leon Rose and I are in the pilothouse of the converted shrimp boat Triple R, his weathered face revealed by the glow of an odd collection of modern and archaic navigation technology. A full sized computer complete with flat screen monitor shows course, speed and depth under the hull along with GPS positioning. Surrounding the computer is a collection of old analog gauges displaying engine RPMs, oil pressure and temperature each with an arrow indicator in the green range. He’s been doing this for many of his 65 years. A man of measured words, he says, “We might get some weather this trip.” The Triple R, handmade in North Carolina, is constructed entirely of cypress wood, chosen for its ability to repel both the weathering effects of salt water and the many worms that can damage a hull by boring holes in it. At 68 feet in length, she has been in service since 1966 and was originally configured to trawl shrimp. With subtle modifications, her present mission is to harvest the Horseshoe Crab.

Captain Rose informs me that his quarry is not in fact a crab at all, but a member of a branch of the arachnid family, a hardy, prehistoric creature that has remained essentially the same for millennia. You will not find them on anyone’s dinner menu; honestly, between the pincer-tipped legs and the helmet-like shell, there just isn’t much of them to eat. Menacing as the sharp spine, or telson, protruding out the back of the Horseshoe crab is, its primary function is to right the crab should it find itself on its back.

So why are we out here tonight? The refined component of the crab’s cobalt-blue blood is used to test the sterility of medical intravenous solutions – should the introduction of this plasma to the solution produce clotting, then contamination is indicated. It is this reaction that makes the harvest and bleeding of Horseshoe Crabs invaluable to medical science. To date there is no synthesized alternative to this natural immune response. The amount of blood extracted from each crab amounts to about a tablespoon and is well-tolerated by the crabs which through their immune system detect the injury at the extraction site and clotting there stops the withdrawal because of restriction due to the clotting.

Earlier, the previous night’s catch of 800 or so crabs were transported in an air-conditioned trailer from the plasma extraction laboratory in Salisbury, Maryland and stacked (still alive) on deck in large plastic tubs. Deck Hand Jeremy Roberts (known as Cowboy aboard ship) points out the small hole punched in a corner of the shell of each crab that was selected and bled by the laboratory. This ensures that this crab will not be included in any more of this years harvest. When the punched crab molts the following Spring, the shell will be intact.

As the Triple R makes way out to sea, the deck hands Cowboy and Captain Rose’s son Leon, Jr., or “LT” on deck, lower the dredge booms from vertical to horizontal in order to better stabilize the vessel. LT informs me that he is the middle “R” in the name of the boat along with his father and the owner of the boat, Rod Roberts. Then he tells me where to position myself to avoid the many lines and hazards found in the confines of the busy stern work area. Their choreography on deck is well rehearsed as they move from lowering the booms to dumping the many tubs of previously bled crabs over the sides of the rolling vessel. Great care is taken to cleanse each of the emptied tubs so that they will remain fresh and no contamination will come to this night’s catch.

Captain Rose tells me that at this time of year (late summer) there is a mass migration of Horseshoe Crabs out of the shallow back bays into the deeper waters of the Ocean where they spend the winter. LT and Cowboy, now shod in white waterman’s boots, make light of my clean new boots by asking where I got my “North Carolina Florsheims” and remark that “they shor’ is clean Tangier wingtips.” Before this night is through they are not so pristine.

Captain Rose reduces speed and the prepared nets are lowered and held open just above the ocean floor with the help of two heavy trawler doors, which plane at angles slightly outbound from the ships course holding the nets open and apart. Ahead of the nets is the “Tickler” chain that connects the two nets, limits the separation, and also serves to disturb the crabs from the bottom, allowing them to be scooped up in the nets.

With nets extended, we steer a pattern that follows contours of the bottom which best yields crabs. The Ocean floor, like much of the land on the Eastern shore is laid out by the action of waves to create ridges and valleys. The crabs follow paths of least resistance and use the valleys when they are in motion. A closely guarded secret, the location of the crabs is affected by Moon phase, tides, temperature, wind speed, and sometimes just plain good luck. Captain Rose tells the story how he trawled just behind another boat working the same area and the lead boat produced few crabs. Following behind, Captain Rose filled both net bags simply because his speed was slower allowing the Tickler chain to disturb the crabs right into the net instead of passing over them. Now as the nets fill, they grow heavy and the boat’s forward momentum meets resistance. All hands stand ready when the boat is put to slow forward speed. The port net is drawn closed with a line threaded through a pulley on the vertical boom. Another line connected to the closed net bag is then slung around the boat’s diesel powered winch. The bag is then drawn up and out of the water and swings in board with the aid of the vertical boom. The boom creaks and groans under tremendous weight of the full bag of crabs as it is positioned over the stern of the boat.

LT pulls on the release line, which opens the net at the bottom, just as it swings to the center of the stern. The bag disgorges a heaping mass of writhing, slithering and crawling creatures all eerily lit under the boom floodlight. It is a nightmare of spines and claws all in upward projecting positions. Cowboy wades into the mass to quickly toss overboard the stingrays, skates and flounder that have found their way into the net. He then collects any Horseshoe Crabs with a punch hole and casts them over the side. The number of previously bled crabs is surprisingly few and they are every bit as robust as the unmarked crabs. Cowboy compares smaller crabs to a measuring guide stick. Should they not meet the minimum size of 7 inches from point to point on the shell, they are released. Crabs under this limit will not fit in the laboratory’s bleeding racks and could be harmed.

The sharp, spine-shaped telson makes an efficient handle to grasp the crabs, and LT and Cowboy wear heavy gloves. They place the crabs 7 or 8 to each plastic tub and stack each tub 5 high on the forward deck. The banter between LT and Cowboy is snappy, enlivened by a successful trawling night. We have been out for several hours and have filled our quota of 800 crabs. Sweat rolls down Cowboy’s face as he recounts the time they recovered an intact toilet from the net. “Could’ a hooked it right up” he adds. LT chimes in that the many wrecks on the bottom wreak havoc on the nets and are a constant expense to repair. The port net bag takes about an hour to cull and pack as various other species of crabs caught with the Horseshoe Crabs skitter under foot. What is left is swept up and pushed out the scuppers into the sea and the deck is hosed with fresh seawater.

The starboard bag is then hoisted on deck and its contents spill out in a pile to fill the remaining tubs. This night, the second bag produces more than is required by the medical laboratory that has a capacity to bleed 800 Horseshoe Crabs a day. What is left on deck is returned to the sea unharmed.

With a telling smile, Captain Rose yells to the boys to clean up the deck and hoist the nets to make ready for return to port. It has been a very productive evening, a good haul. In the Pilothouse, Captain Rose reflects that the numbers of crabs seems to be holding steady. Their habitat in these waters has yet to be adversely affected by the activities of man and since they are returned alive to the area where they were caught, little population impact is observed. The lightning to the west, now closer, streaks out of the sky; but it looks like we will just beat the growing storm.

At the end of the evening the work of unloading these live crabs is done in a hurry as the clock is running on the amount of time they can be out of the water. They will be off to the laboratory, contributing a small amount of blood for a large benefit to mankind. While most are turning out your lights to go to bed, the crew of the Triple R will be out to sea, boom lights glaring into the night swinging heavy net bags of Horseshoe crabs aboard. And, should one ever be so unfortunate as to require an intravenous solution, the sterility of the solution was probably tested with components of blood from a 300 million year old creature, collected on a 40-year-old boat by two generations of Horseshoe crab trawlers.