Maine has an abundant supply of lobsters – total catches during several of recent years have been record-breakers – and scientists can find and track Homarus americanus all along the crustacean’s path of development from the larval stage to the large offshore broodstock. Odd then, that a Maine scientist wants to expend energy trying to grow out tiny hatchery lobsters to a viable, trackable size.
But Dr. Brian F. Beal of the division of Environmental and Biological Sciences at the University of Maine in Machias offers two reasons: It’s a personal challenge to see if he can figure out how to do it, and if the Maine stock happens to collapse, scientists will know have more tools to help restore it.
“We know we can hatch lobsters and grow them to the size of a penny, then release them,” said Beal. “But to try to compartmentalize them and try raising a few to a larger size so we can tag them before release doesn’t pay. We didn’t know what little lobsters eat.
“I asked myself why we couldn’t take the best of both worlds – raise hundreds of thousands of larval lobsters until they were big enough to survive without the expense of feeding them,” Beal said. “I researched feeding them, but wasn’t getting too far. Then it dawned on me – small things must eat small things and everything in the ocean starts out small… ”
Beal tested his theory in Ireland where scientists don’t have the same kind of luck finding certain stages of small Homarus gammarus – a lobster nearly identical to the East Coast species. Researchers even believe they were once the same lobster species that evolved through separation to exhibit their slight differences.
Besides the European lobster’s mysterious ability to hide in the small “benthic” stage, another area in which the species deviate sharply is abundance. In Ireland, lobster catches are well below those of the U.S. – especially Maine – or Canada and researchers have been working hard for years to figure out why. Limiting their investigation has been the failure of European researchers to locate the benthic lobsters. In Maine, scientists turn over rocks on cobble bottom and routinely find tiny lobsters.
“We worked on them in the U.K., Norway and Italy to find out what happens to the smaller ones in the benthic stage, where Maine has them all over the place,” said Dr. John Mercer, former head of the National University of Ireland at Galway’s shellfish lab in Carna. Mercer is now at the Galway campus’s Martin Ryan Marine Science Institute.
“We had people like [Maine lobster scientist] Rick Wahle use their numbers to say how good settlement on plankton is, but we can’t find them at all,” said Mercer. Between 1994 and 99, Mercer said researchers – including Wahle – “hoovered up large sections of the Irish Sea, the North Atlantic and the Mediterranean. We couldn’t find one. We can find them from 20 mm and up, but we’re missing an entire stage.”
During that time, Irish harvesters pulled in between 15 and 30 pounds of lobsters per 100 traps at their season’s peak, while Maine harvesters landed closer to 200 pounds per 100 traps. In 1991, Irish lobstermen landed 90,000 pounds of lobsters while Maine landed 31 million pounds. The Republic of Ireland and the state of Maine are similar in size: Ireland’s area is 27,136 square miles compared to 33,215 in Maine.
While the low Irish lobster catches remained static, at the Carna lab and other places around Ireland, researchers hatched tiny lobsters and put them in the sea, with no way to measure their survival or know if larger lobsters caught later came from these hatchery stocks.
If the tiny ones can’t be found, thought Brian Beal, Ireland needs a low-cost way to grow the hatchery lobsters to a larger size before depositing them in the ocean. This way the small lobsters would be large enough to tag and their survival and progress could be recorded.
Growing out seafood species is generally an expensive as well as space- and labor-intensive process. Besides, no one really knew what tiny lobsters eat. Beal said he had wracked his brain to find a solution to the feed, the costs and the space.
“One day I woke up with an idea that was so simple, I couldn’t believe it,” said Beal, a former lobsterman. “I thought: what tiny things could tiny lobsters eat? Then it dawned on me, if you put a boat or a rope or a pole in the water and come back in three weeks, what’s on it? Stuff! I figured if I just put the tiny lobsters in a protected place in the ocean, they could eat whatever grew there.”
“It was such a weird idea that no ever thought about doing it,” he says. “The thinking has always been that you could produce many, many numbers of small lobsters to be released, or you could produce a few large ones, continue to feed them in the hatchery and then release them. No one really seemed interested in trying this technique.”
Generally, hatched lobsters are raised to about the size of a penny, meaning they are easy prey for larger predators and their survival rates are presumed to be very low in the wild. Beal wanted to raise them to a 2- or 3-inch size, strong and healthy enough to molt.
Beal went to Ireland on a grant to test his theory at the Carna lab. He put the tiny lobsters in petri dishes and mesh containers and suspended them three feet off the ocean floor.
“I wanted to see if we could find a way to put these small lobsters out in their natural environment in individual containers and have them survive and grow by letting them feed on the type of organisms that typically foul things like wharves and the bottoms of boats,” said Beal.
Beal had visited Ireland before, contributing tips from the Cutler, Maine, hatchery to help the Carna hatchery improve its average 10 percent lobster survival rate. Cutler’s survival rate for tiny lobsters was then 30 percent to 50 percent.
His “stuff” theory worked. Beal spent 10 months at Carna growing the tiny lobsters to a more viable size.
“Not only did they survive, they grew,” he said. “About 50 to 75 percent of the animals survived for the 10 months of the experiment.”
“Brian feels that if you put them out when they’re larger, they have a better chance of survival,” said Mercer. “It’s a possibility. They grow well, although survival is variable. And it’s relatively inexpensive as science experiments go. But when you think about producing them in large numbers for restocking the fishery in an ongoing manner, then there’s obviously a finite cutoff point. We can’t spend as much as the animal is worth.”
Mercer believes the next step is to find a way to replicate Beal’s research on a larger scale while keeping the costs down. The Carna lab is undergoing major reconstruction so the lobster experiments had to be halted temporarily, but Mercer says they will start up again when construction is finished.
However, Beal is conducting his research again in Maine using a $10,000 grant, hoping to improve the catch in the future. Despite Maine’s enormous catches of recent years, some scientists still fear the stock could collapse as a result of just one bad year class.
“There’s a significant threat in not understanding what controls the dynamics of the lobster population and how long we will be able to maintain this level,” said Beal.
Beal recently received word that his research has been awarded a three-year, $184,000 grant from the Maine Marine Research Fund. The funds will cover the cost of equipment and supplies and allow the research to continue for three years.
“We’re just trying now to find the maximum size we can grow them to,” said Beal. Later, if funding can be found, he may try tagging them to track their survival and progress.
Meanwhile, Mercer thinks he may finally have figured out where the little benthic-stage lobsters go in Ireland – into deep cracks in the ocean floor. Now he just needs a big grant to pay for fiber-optic probes to test his theory.