Nov. 8, 2019 /PRNewswire-PRWeb/ --
When it comes to survival, the freshwater mussel's approach to
reproduction could give even Stephen
King a case of the shivers.
When it's time for their microscopic larvae to continue
developing, female mussels must parasitically infect a specific
host species of fish with their offspring.
Some mussels eject their larvae into the water hoping they'll
passively infect nearby fishes, but others take a more novel — some
might say "cunning" — approach.
There are mussel species whose larvae are in packets disguised
as small fish or insects, which larger fish attempt to eat,
infecting themselves in the process. Other mussels have fleshy
mantles that resemble prey desirable to their host fish species.
When a hungry fish hones in on this "easy" meal, the mussel expels
its larvae at the peckish diner or clamps its shell around it,
restraining it and directly infecting its skin, fins and gills.
Terrifying as these Alien-like sneak attacks sound, infected
fish aren't harmed by their hitchhiking guests, who eventually are
covered over by tissue and have little impact on the fish's health
or nutrition. After a few weeks, the juvenile mussels are ready to
drop off, sometimes having been carried upstream to new locations
they otherwise couldn't have reached.
Recently, the Tennessee Aquarium joined forces with Tennessee
Wildlife Resources Agency-managed Cumberland River Aquatic Center
in Gallatin, Tennessee to lend a
helping fin to the host-less offspring of four endangered species
of native bivalves.
"They reached out to the Tennessee Aquarium Conservation
Institute because we are well-known for raising fishes," says
Aquarium Science Programs Manager Dr. Bernie Kuhajda. "They were hoping we could
propagate some fish for them to use in raising their mussels."
Under pristine blue skies, a team of freshwater specialists from
the Conservation Institute waded into South Chickamauga Creek to
bring back about two dozen Common Logperch to their propagation
facility near downtown Chattanooga. Less than an hour later, they
more than met their quota, the fine-meshed seine net having
collected about 30 Logperch in addition to a host of crayfish,
insect nymphs and wriggling masses of Mountain Madtoms, Warpaint
Shiners, Stonerollers and other fish species.
"That was definitely the easiest collecting trip I've ever been
on. It doesn't get much better than that," says Aquarium
Reintroduction Biologist Meredith
Harris. "It's really encouraging to have a stream that has
such a healthy level of biodiversity like South Chickamauga Creek
right here in our backyard."
The sleek, tiger-striped, green and gold Common Logperch can
reach about seven inches in length and — as its name suggests — is
widespread from Ontario to
Alabama. Although it isn't
considered imperiled, the Logperch's offspring will be vital to
efforts to raise endangered Dromedary Pearlymussels, Cracking
Pearlymussels, Fanshells and Snuffbox Mussels, all of which can be
found in the Tennessee and
Cumberland River watersheds.
Once infected by mussel larvae, fish develop resistance to
future infections. As a result, individuals generally only play
host to a single generation of mollusks.
"You can't just go out and catch fish and bring them in because
if they've already been infected, it won't work as well," Kuhajda
says. "And we don't have any way to test the fish to see if they've
already built up an immunity to being infected."
Early next year, the offspring of the collected Logperch should
be large enough to be shipped to the Cumberland River Aquatic
Center. By only sending fish that were hatched and raised at the
Aquarium's freshwater science center, each one will be accustomed
to the environment of a hatchery and guaranteed to have a clean
That should make them the best possible hosts for the mussels,
"This way, the Aquatic Center can infect them with larval
mussels, and they won't get overly stressed or potentially reject
them," he says. "They'll be relatively happy Logperch, even though
they have little mussels attached to them."
The partnership between the Aquatic Center and the Aquarium will
continue for two years with new Logperch being sent over once
previous groups of fish have been infected and their bivalve
"Recovery of threatened and endangered species requires
collaborative conservation efforts, says Dr. Dan Hua, Tennessee Wildlife Resources Agency
Senior Scientist at the Cumberland River Aquatic Center. The fish
host is critical in mussel propagation and restoration. Cooperating
with our partners, such as the Tennessee Aquarium Conservation
Institute, we will successfully keep the wheel running in this
"We're all in this together. It's going to take everybody's
effort to recover these animals," Harris says. "We've got a lot
more work to do, but we now have the fish and that's an important
Tennessee waterways are host to
more than 120 species of mussels. More than 90 percent of the
continent's mussels can be found in waterways within 500-miles of
Chattanooga. Many mussels can live
for decades, during which time they are constantly siphoning food
from the water flowing over and past them.
"As they do that, they filter out contaminants," Kuhajda says.
"If we want water that's safe to drink, to swim in and to fish in,
mussels are an integral part of that system that gives us clean
SOURCE Tennessee Aquarium