Roger Williams University
professor Dale Leavitt and two undergraduate students take measurements of some of the farm’s largemouth bass. (Rowan Sharp/ecoRI News photos) |
By ROWAN SHARP/ecoRI.org News contributor
ROCHESTER,
Mass. — Dale Leavitt told me to meet him at the 7-Eleven in this small town of
about 5,000. I wouldn’t be able to find the fish farm on my own, he said. “It’s
way out in the woods — it would be impossible.”
He pulls up in a pickup — a cheerful, mustached man
with slightly wild silvering hair. He wears a weather-beaten baseball cap and
T-shirt, both advertising the marine biology program at Roger Williams
University, where he teaches part time. He has blurry tattoos on his forearms,
including one of a cartoonish, polka-dotted octopus.
Leavitt grins at me in the hot midday sun. “You need a
cold drink? No? Okay,” he says. He climbs back into his truck and I follow him
down Route 28, until he veers into forest. Soon we’re rolling slowly down an
unpaved track, just rutted wheel marks with grass tufting up between them.
Golden dust billows up from our tires so thickly I can barely see. We leave the
woods for a vast open space: cranberry bogs, I’ll soon learn, where a network
of dusty roads lace through the wet lowland.
The 15
6-by-8-foot fish pens are
stocked with juvenile largemouth bass.
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Leavitt parks on a little scrap of solid ground amid the
bogs, where a murky pond and a bank of solar panels are the only clues to the
one-of-a-kind innovation hidden here. But this unassuming exterior packs a
punch. Leavitt, cranberry farmer Brad Morse, Roger Williams University
engineering professor Charles Thomas and a handful of undergraduate students
from Roger Williams University have turned hard-won Environmental Protection
Agency (EPA) grant money into a solar-powered, self-cleaning fish farm that may
prove two to three times more efficient than conventional fish farms, at scant
environmental cost.
These hidden cranberry bogs hold a system that could
profoundly impact the future of sustainable food production.
Fish food
We climb out of our vehicles; sun beats down on the bogs, which are subtly terraced so that water flows effectively between them. Big red dragonflies hover in the hot air. A slight wind stirs.
We climb out of our vehicles; sun beats down on the bogs, which are subtly terraced so that water flows effectively between them. Big red dragonflies hover in the hot air. A slight wind stirs.
Leavitt — his students call him Dale — is in his element
here. He produces a plastic container of what looks like dog food pellets —
Purina Fish Chow, actually — and happily leads me over to an unnervingly
rickety plank onto a metal walkway over the pond. Weathered boards delineate
the 15 6-by-8-foot mesh-sided fish pens.
“It’s very impressive to see them feed!”
Leavitt promises, sprinkling pellets into a pen. Soon the surface roils with
activity: 6-inch juvenile largemouth bass, voracious eaters, which, by fall,
will grow into 14-inch, one-and-a-quarter-pounders. Each pen is a module that
can be lifted out with a backhoe. The mature fish will be sold at Boston’s live
seafood markets or over-wintered for pond stocking this coming spring.
Each pen can comfortably hold 100 bass, though some
aren’t yet filled. Soon three of Leavitt’s assistants drive up with more fish
in plastic tanks. Leavitt bought the bass as 2-inch hatchlings from a Delaware
hatchery last winter; he and his students raised them to their current size in
a Roger Williams University laboratory.
Matt Griffin, who works on shellfish restoration at the
lab, dons rubber boots and waterproof coveralls so he can stand in the
waist-deep pens. Joel Lashomb, a rising junior and marine biology major at
Roger Williams, and Danne Elefante, a recent graduate, move the fish from tanks
to pens with a net.
“We got a dead one,” Lashomb reports.
“Just one?” Leavitt asks
“Should I throw it …?”
“No, no,” Leavitt says. “Go bury it. Give it a burial.
Give it a fish burial. Over there on that side.” The quaint ritual is actually
to outwit otters, which can be troublesome predators.
Multipurpose bog
Usually, farmer Morse is here, too, chumming with Leavitt’s students, or tending the fish and cranberries. He’s out today, but this enterprise owes its beginnings to a struggling late-1990s cranberry market that left Morse searching for other options. Morse is a fifth-generation grower who has farmed the 65-acre bog surrounding us since 1971.
Usually, farmer Morse is here, too, chumming with Leavitt’s students, or tending the fish and cranberries. He’s out today, but this enterprise owes its beginnings to a struggling late-1990s cranberry market that left Morse searching for other options. Morse is a fifth-generation grower who has farmed the 65-acre bog surrounding us since 1971.
By 1999, cranberry prices were so depressed that many
farmers feared selling their land for development was the only viable option.
But Morse had another idea.
Eighteen
200-watt, 24-volt solar panels power the fish farm’s water pump.
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“I was looking for ways to diversify,” he says in a
telephone interview. He connected with the Massachusetts Department of
Agriculture, where Leavitt then worked as an aquaculture extension agent.
Leavitt found funding to help Morse launch a fish farm, and the two became good
friends as they worked together on an elegant partitioned aquaculture system,
kept clean by phytoplankton.
It was a two-pond design: one pond for the fish, with
water circulating by paddle wheel through a wider, shallower pond — a converted
cranberry bog — where naturally occurring algae absorbed fish waste from the
water. An aerator gave the needed oxygen boost.
The farm was “a learning curve,” Morse says, but it
supplemented his income until the cranberry market recovered. The project’s
Achilles’ heel, however, was its fuel consumption. The bog is too isolated for
an electricity connection; a diesel generator powered the paddle wheel and
aeration.
In 1999, diesel had cost 76 cents a gallon. By 2006, it
was well over $3. The fish were no longer profitable; Morse converted the
filtration pond back to cranberries. Leavitt turned his attention to other
things.
But Leavitt’s passion has never strayed too far. He
joined the Roger Williams University biology department and continued doing
aquaculture outreach, advising new oyster farmers and even designing a
solar-powered shellfish growing system. His lab also grows oysters for
restoration of Narragansett Bay.
In 2008, Leavitt called Morse to say, “Brad, I’m ready to
start fish farming again.”
This time, Leavitt had a different plan. He applied for
an EPA grant to work with undergraduates in developing technology for
sustainable living. Morse was more than willing to get involved.
“It’s a lot of fun,” Morse says, of growing fish. “It’s
the biggest fish tank of all.”
Morse, Leavitt, and Thomas worked with a team of senior
engineering students to “completely revamp the concept” of the fish farm. They
modeled the new system on the flow dynamics of an automobile turbo-charger — a
lucky stroke of inspiration from a student. They designed a single-pond system,
with waist-deep fish pens on one side and a shallow, 18-inch algae filtration
area on the other; algae need plenty of sunlight to photosynthesize fish waste,
so depth matters. A single pump would aerate and circulate the water, and the
whole pond would only be a quarter acre.
Goodbye
diesel. They were going solar.
The grant process was competitive. They drew up a
proposal that won $10,000 for planning, then presented the project to the EPA
in Washington, D.C., competing with undergraduate groups from around the
country for the $95,000 implementation grant. They not only won the grant, but
also were invited back the following year to share their progress.
Morse dug the new pond, which they lined with heavyweight
woven plastic and filled with groundwater. To run the pump, they installed 18
200-watt, 24-volt solar panels, which feed a bank of nine 24-volt battery
systems protected from the elements inside a shipping container. Leavitt is
frustrated with the current pump, whose capacity he doesn’t know precisely. But
he and his students have designed, and will soon install, a more effective pump
that he says will move 700 gallons of water a minute.
Bog of life
Leavitt is enjoying himself here. He stoops and catches a dust-colored, half-inch toad, and holds it out in cupped hands. He then spots a better prize: a small turtle in the pond’s filtration area, poking its head above the surface like a periscope.
Leavitt is enjoying himself here. He stoops and catches a dust-colored, half-inch toad, and holds it out in cupped hands. He then spots a better prize: a small turtle in the pond’s filtration area, poking its head above the surface like a periscope.
“Hey, Joel, go get a net and catch that turtle,” he tells
his student Lashomb.
“Why?” I ask naively. “Is it a predator?”
“Oh, no. There’s a koi pond behind the research building
on campus. I’d just love to get some native turtles in there,” Leavitt says.
Lashomb is stalling. “There he is again, Joel! See him?
Right there!”
Lashomb, with the net, walks the perimeter of the pond.
“Watch out!” shouts Leavitt, grinning. “He might be a 20-pound snapper. That
might just be the tip of his nose.” To me, he says, “He’s gonna slip and fall
in. Don’t tell him I said that.”
Lashomb doesn’t fall in — and he doesn’t get the turtle —
and soon it’s time to work. Leavitt and his three assistants go from pen to
pen, corralling fish into a corner and netting them in groups of six, which are
quickly weighed, measured and released.
Griffin stays dry in his waders, but Lashomb and Leavitt
are waist-deep, in bathing trunks. Lashomb hops around as the fish swarm his
legs. The water, though murky, has no smell. The phytoplankton are doing their
job.
Leavitt jokes with his helpers and talks sternly to the
fish as he measures them nose to peduncle, the last fleshy part of the tail
before the fin starts. “Easy,” he tells the fish. “If you stop struggling,
you’ll get out of here much more quickly.”
Between measurements, Leavitt surveys his watery green
domain. “We’re going to start growing hydroponic veggies on floats,” he says.
“I can envision this thing being lined up with floats of plants next summer.
But that’s just kind of a lark.”
The fish production, though, isn’t a lark. It’ been
meticulously planned, and though this is the farm’s first year in operation,
Leavitt is confident. “We had done our homework” the first time around, he
says, noting that he expects they will break even with feed costs and sales
this year.
“The potential’s there to do well,” Morse says.
Eliminating the waste
At the end of the year, they will write a final report to the EPA, and privatize the farm, transitioning it from research project to business.
At the end of the year, they will write a final report to the EPA, and privatize the farm, transitioning it from research project to business.
No one has ever run a system like this on solar power,
they say. The design itself is cutting-edge. The key is its ridiculously
efficient waste removal; the partition system, in fact, was first designed at
Clemson University, in South Carolina, for sewage treatment. Clemson
researchers later made the jump to aquiculture, but the system is still little
used by mainstream fish farmers.
While fish farming comes under frequent fire from
environmentalists, marine farms take most of the heat. Net-pen salmon farms,
for instance, have been roundly criticized for the high quantities of waste
they release into the ocean. And escaped fish may bring the diseases of
captivity with them into the wild.
Leavitt notes that contained freshwater operations — the
most common in the United States are catfish farms — have a lower ecological
impact. But waste management also troubles traditional freshwater fish farmers.
As anyone knows who has killed a childhood goldfish by neglect, fish are
poisoned by high levels of their waste in water.
Though vaccination has helped taper off the use of
antibiotics in farmed fish, unhealthy fish are more likely to be medicated. And
a farmer’s ability to keep ponds clean is often a chief limiting factor in the
quantity of fish that can be raised healthily.
Traditional farmers struggle to find feed that will
reduce toxicity in fish waste. Some farmers drain their ponds annually; this
water must be managed carefully or it can cause environmental harm. Other
farmers install mechanical filtration and waste removal systems. But Morse and
Leavitt’s can more than triple a fish farmer’s output, while keeping water
clean.
“In a natural pond, you could get 500 to 1,000 pounds of
fish an acre; with this system you can get 1,000 to 15,000 pounds of fish,”
Leavitt says. The quarter-acre pond may produce up to 1,875 pounds of fish this
year.
Leavitt is well positioned to spread the word. Busily
connected with farmers and researchers across the nation and worldwide, he’ll
present a paper on sustainable fish farming at an upcoming World Aquaculture
Society meeting. He casually mentions a friend who farms tilapia in Haiti, an
aquaculturist visiting from Tasmania and a D.C.–based company he knows that is
considering solar-powered fish hatcheries.
While Leavitt admits the high-protein fish feed can be a
limiting factor, he sees promise for his system, at a similarly small scale, in
developing countries. The pond in the cranberry bog is small and shallow enough
that it could be achieved with hand labor. And solar technology is getting
cheaper all the time.
“Somewhere down the road, we might take this out and do a
demo project somewhere that it has a lot more meaning than growing a few
largemouth bass in Massachusetts,” he says.
And
with final, scolding words for the last fish he’ll measure today — “Stop
splashing. And stop biting the net!” — Leavitt splashes to shore, climbs into
his pickup and guides me along the maze of little roads out. Looking back at
the forest buffering the bogs and fish farm, you’d never even know it was there.