The conch conundrum

Shelley Edmundson devised the "conch-cam" to study the behavior of captured conch.
Photo by Jason Gale

Shelley Edmundson devised the "conch-cam" to study the behavior of captured conch.

As lobsters high-tail it out of the warming Vineyard waters, commercial fishing seasons shorten, and the number of shellfish closings mounts, the conch remains the most reliable and most lucrative catch for Martha’s Vineyard fishermen.

According to the most recent statistics from the Massachusetts Department of Marine Fisheries (DMF), just shy of three million pounds of conch was harvested statewide in 2012, at a value of roughly $6 million dollars. Vineyard conch fishermen, who accounted for 24 of the 91 permits, hauled in 1,094,127 pounds, adding over $2 million dollars to the local economy. There’s gold in them gastropods.

“Conch” is actually a misnomer — the conch is a vegetarian that lives in warm waters in some of the most exotic locations on earth, and in Florida. The “conch” in Vineyard waters refers to the channeled whelk and to a lesser extent, the knobbed whelk. Channeled whelk eat shellfish, which is why, until recently, they were considered an unwanted predator here. There were even bounties on their egg sacks, also known as “mermaid’s necklaces,” the paper-like disks attached to a string, that are commonplace on Island beaches.

Conch are caught in wire mesh pots, about the size of lobster traps, with a large opening at the top. Rubber strips placed on the outside walls provide purchase for the conch to climb inside to reach the bait. The favored bait is horseshoe crab, which has grown more expensive as its numbers have dwindled, due in large part to demand from the medical industry. An extract of the horseshoe crab’s blood is used by the pharmaceutical and medical device industries to ensure that products are bacteria free.

Except for the occasional gastronomical whim of a local chef, all of the Vineyard whelk is exported. It may end up in Italy as scungilli, or in France, as bulot, but most likely, it will end up in Asia, where whelk is considered a delicacy and can easily fetch over $30 a pound.

Considering how important these sea snails are to the Island, very little is known about them. When and where do they breed? What happens when they’re caught? How many of are out there? Are they being over-fished?

Mastering the mollusk

Vineyard resident Shelley Edmundson has stepped into this void, and as part of her doctoral studies in zoology at the University of New Hampshire, has studied the mysterious mollusk for the past two and a half years.

Ms. Edmundson grew up in Florida and spent her summers in Vineyard Haven with her grandmother. She’s been a full-time Islander for the past 10 years, which made for a long commute when she earned her masters in environmental science at UMass Boston. “I got to know the Peter Pan bus schedule really well,” she said, with a laugh, when she sat down recently at the Times.

Ms. Edmundson began studying Vineyard whelk shortly after earning her masters degree. “Warren Doty and Tom Osmers were doing research on how the Wind Farm would impact fishing, and they asked me to look into the conch fishery,” she said. “I realized pretty quickly that this animal lived in large numbers on Horseshoe Shoal, but it was largely overlooked. Because we know so little about it, I thought it was essential to study whelk biology so we can sustain the species, and the fishery — if it’s not too late.”

Conch scienceIn 2011, to investigate the movement patterns of the whelk, Ms. Edmundson got permission from the DMF to allow four Island fishermen to catch undersized whelks. She tagged 2,000 of them, attaching the small plastic tags with boat epoxy. The fishermen took them back out to sea and marked the location. She didn’t mark any whelks in 2012. This year, Ms. Edmundson tagged 11,000.

“I couldn’t have done this without a lot of help from people on the Island,” she said. With the backing of Mr. Doty and the Martha’s Vineyard Fisherman Preservation Trust, Ms. Edmundson was awarded a Vineyard Vision fellowship. Assistance from Rick Karney, manager of the Martha’s Vineyard shellfish group, was crucial in tagging greater numbers, by enabling her to store more whelks in empty tanks at the Hughes lobster hatchery. This year, she enlisted fellow Islander and Vineyard Vision fellow, and University of New Hampshire undergrad, Tony Lima. “Tony was a huge help with the tagging. It took a lot of time and a lot of glue and made us both crazy, but we did it.” The soft-spoken Ms. Edmundson is equally effusive about the help she’s received from the local fishermen. “Even though they’re juggling a million different things, they’ll take me out,” she said. “One fisherman had a pot with three from this year and one from two years ago. It was like winning the lottery.” So far Ms. Edmundson has recaptured 100 of the 2,000 that were tagged in 2011.

Two years in, the tag system hasn’t been effective at tracking movement. But it has been helpful in determining growth rates, a key factor in determining the minimum catch size. “Age is still difficult to determine,” said Ms. Edmundson. “It’s size that determines sexual maturity.” According to DMF data, about 50 percent of females that are three and three-quarter inches wide are sexually mature.

This September, Ms. Edmundson took another crack at monitoring whelk movement by tagging five channel whelk with a radio transmitter and planting them in one of the great ponds. Sensors on buoys at the pond opening will tell her if and when they head out to sea. “I’m still analyzing data but it looks like one of them has moved into the sound,” she said.

Shelley vision

Ms. Edmundson made extensive use of video and documented previously unseen whelk behavior in her laboratory in New Castle, New Hampshire. She captured a channeled whelk birthing an egg string, a process that takes up to 13 days. She also has the first video of baby channel whelks bursting out of the casing.

Most recently, Ms. Emdundson unveiled the “Conch-cam” a Go-pro camera rigged to a conch pot. “I want to learn their diel [24-hour period] patterns,” she said. “Is there a difference when they enter the trap in day or night? What’s the moon cycle? The tide cycle? It will also be used to test different baits.Ms. Edmundson has already made some discoveries. “They know when they’re caught,” she said. “If you think they have no sense and they operate on a purely base level, you’re wrong. Once they’re in the pot, pretty soon they start doing circles. They start crawling up the sides and fall, over and over and over. They can’t make the angle out of the pot.”

The time lapse footage has also shown a healthy spider crab population. “It’s unbelievable how many spider crabs you see. It makes you dizzy.”

Conch census

The question remains: are conch being over fished? The question was first raised in the late 1980s. International demand made conch more lucrative and as fin fishing dropped off dramatically, conch went from being by-catch for trawlers to being the main catch. With more trawlers fishing more pots smaller fishermen were cut adrift.

According to the Massachusetts Division of Marine Fisheries, catches have held steady over the past decade, statewide and on the Vineyard. The catch in 2002 was 1.4 million pounds. In 2011 it was 1.3 million pounds, and over a million pounds in 2012.

“We know that their abundance is substantially lower than two or three decades ago, but it’s hard to tell what the overall population is doing,” said Dan McKiernan, deputy director of DMF.

But people who work in the business are concerned.

“It’s become like a gold rush here,” said Danny Chan, president of Aqua World Seafood in Vineyard Haven, and one of the main conch buyers on the Island. Mr. Chan estimates his business is off by about 20 percent this year. “I think most people would tell you that business is down,” he said.

“It’s been slower since there’s been more boats out there,” said Donald Benefit, a veteran conch fisherman out of Edgartown, talking to the Times from his boat on an unseasonably warm November day. “The amount of conch is down because there’s a lot more boats fighting for certain areas.”

According to the DMF, the number of conch pots doubled between 2005 and 2010.

Recently, the DMF and UMass Dartmouth professor Brad Stevens, made a sobering discovery — the minimum legal size that’s been on the books didn’t allow for the whelk to reach sexual maturity.

“The size limit was set for economic, not biological reasons,” Ms. Edmundson said. “The minimum size was arbitrarily decided in the 90s, based more on marketability, the size of the meat versus the cost of processing. It had nothing to do with biology or sexual maturity. It wasn’t protecting any of the females.”

On July 19 the DMF announced new regulations. Starting on January 1, 2014, the minimum shell width of two and three quarter inches will be increased by one-eighth of an inch for the next two years. A new, more accurate measuring gauge was also distributed. The season will still last from April 15 to December 15.

Mr. Benefit said he already practices his own form of conservation. “I leave them alone in August,” he said. “That’s when they mate. I take all my gear out of the water and I let them do what they gotta do. I wouldn’t want anybody bothering me at home, you know? I look to the future. I’ve got a daughter who likes the water.”

Conch conclusion

Ms. Edumdson says she has much more data to collect before she can make any concrete conclusions about the conch population, mating habits and movements. She’ll be going out to get transmitter readings and to download video footage, as often as the weatherman and fishermen benevolence will allow.

“I would say that the observation and videotaping of the egg laying process and learning that the lab whelks took between 11-13 days to deposit a complete egg string has been one thing that I have learned thus far.” she said. “Culturing egg strings in the lab at temperatures mimicking the Lagoon — it took eight months for the juvenile whelks to hatch, that’s another interesting fact. There’s so much to learn still. I think I’ll be 90 before I’m done with this.”