48 Scientific American, May 2022
mals. Historically, intensive fish farms have been linked
to a lot of bad things: declines in biodiversity, habitat
loss, the overuse of antibiotics, and animal welfare
abuses, especially in Asia and Latin America. And in
recent years fish die-offs and other problems have
plagued North American sites. But Newell represents a
new breed of scientist with innovative approaches to
growing fish that are both economically and environ-
mentally sustainable. His kludgy mussel-growing appa-
ratus generates three times as much seafood as tradi-
tional mussel farms. And because free-floating mussel
larvae seed the ropes naturally and eat whatever phy-
toplankton drifts their way, Newell’s farms require noocean temperatures, among other threats, nearly all of
Maine’s commercial fisheries are in free fall. Maine cod
is crashing, as are local shrimp. The wild mussel catch
declined from 25 million pounds to a mere nine million
over the past two decades. And lobsters, by far the
state’s most profitable catch, are scuttling north to
cooler Canadian waters. None of this bodes well for the
state’s once robust seafaring economy: the average age
of a Maine commercial fisher hovers above 50, suggest-
ing that many young people have lost faith in the work.
As one wild fishery after another falters, the future
of Maine—and, some say, the future of seafood—may lie
in aquaculture, the cultivation of aquatic plants and ani-AFTER THE
MUSSEL ROPES
are raised by
Pemaquid oper-
ators, a machine
scrapes off the
shellfish, and
they are sorted
into bins.