When docked in its homeport of Woods Hole, Massachusetts, the Bigelow looks like a small cruise ship. The stark white vessel is about as long as a hockey rink, with five different decks, and bunk space for up to 39 people. But on closer inspection it’s clear that the Bigelow isn’t cruising tourists from port to port. Complex machines are carefully positioned all around the deck and above the wheelhouse, on the uppermost portion of the ship, half a dozen sensors and radar scanners spin tirelessly. At the back –or “stern”– of the vessel, giant green fishing nets hang on sturdy steel winches, ready to haul up creatures from the bottom of the Atlantic Ocean.
It’s spring survey time on the Bigelow. The crew fish for about two weeks in a predetermined area, their long nets in the sea for twenty minutes at a time. Teams of two survey scientists count and measure the fish caught by the net, separating different species into individual baskets and weighing the bulk. Some fish are measured individually on an electronic measuring board.
“Our job is to figure our how many fish are in the ocean and where they are,” said David Chevier, who works for the National Marine Fisheries Service (NMFS) in Woods Hole, Massachusetts. Chevier is a computer programmer at NMFS, but a few times a year he escapes his cubicle and heads out on the Bigelow with 14 other NMFS employees to work on the survey cruises. “We use the data we collect to create laws that protect our environment, fisheries, and fishermen.” These laws can help determine how much of a specific species it’s safe to take out of the ocean without potentially damaging the whole ecosystem.
Sometimes survey workers go beyond recording merely weight and quantity, and gut fish to determine their gender and their age. For many bony species, like cod or haddock, the inner ear bone, or the otolith, is sent back to the lab on shore and used to determine the fishes’ ages. Gathering the ear bones can be tricky, even for a seasoned survey scientist. The otoliths of three-foot long codfish are less than half the size of a dime and the scientists extracting them are standing on a rocking boat wear big, stiff gloves and do the dissection with what looks like a steak knife. Not surprisingly, not all of the ear bones end up making it back to land.
Marine mammals usually stay clear of the fishing nets, but a few times each trip a wayward dolphin, seal, or whale will try to feed on fish in the net, and get caught up and hauled on board. If the animal is alive, the crew gets it back into the water as fast as possible, but if it’s dead , the crew puts the body on ice until a scientist can perform a necropsy, the animal version of an autopsy, to figure out if the animal died because it was sick or if it just got caught in the net.
On a survey trip, the nets catch everything from tiny squids the size of your hand to tunas as long as a basketball player is tall. Atlantic torpedo rays look like unremarkable, three-foot long brown blogs ? with tails, but they can actually emit an electric shock strong enough to knock out a person! Even with the exciting rays and sharks that make it on board, sometimes survey trawls seem to catch a whole lot of the same species over and over again. Dogfish, a super hardy fish that look like tiny, foot-long sharks always clog up the net, leaving the scientists to whine until the next interesting haul comes in.
Chevier laughed as he described the twelve-hour shifts on the Bigelow, “We have fun, but we are basically covered in fish guts for most of the day. Thankfully, we have rubber pants.”