Revitalizing Michigan’s lake sturgeon
populations
By BOB GWIZDZ Michigan Department of Natural Resources
Lake sturgeon – evolutionary ancients that have lived in
the Great Lakes almost forever – have something in common with Michigan’s salmon,
which didn’t even live around here until a half century ago.
Both types of fish spend most of their time in big lakes but
run up rivers to spawn; and they both show surprising faithfulness to their
natal streams.
Sturgeon have evolved in the Great Lakes system for so long
that they are genetically different from river to river.
“It’s possible to catch a sturgeon in Lake Michigan,
genotype that sturgeon, and we can tell which river it came from,” said Ed
Baker, a research biologist with the Michigan Department of Natural Resources.
That fact isn’t lost on fisheries managers who are
attempting to revitalize Great Lakes sturgeon populations.
|
The multiple agencies involved in the program – the Michigan
DNR, Wisconsin DNR, U.S. Fish and Wildlife Service, and the Little River Band
of Ottawa Indians – have concluded that rearing fish on site in the streams
they are rehabilitating is preferable to distributing them from a central
facility, such as the Black River Sturgeon Hatchery in Cheboygan County, which
is the Great Lakes’ most productive sturgeon facility.
They have also found that getting the egg stock from the
river in question is better still.
There are currently eight sturgeon-rearing facilities in
the Great Lakes.
In addition to Black River, these include two facilities in
Wisconsin, three in Michigan’s Upper Peninsula, one on the Kalamazoo River, and
the one that started the movement to rear sturgeon streamside, the facility
operated by the Little River Band on the Manistee River.
Begun in 2004, the Manistee River operation keeps getting
better, said Corey Jerome, the fisheries biologist with the tribe.
“We’ve seen some substantial increases in our release
numbers over the years,” Jerome said. “We’ve released just over 1,200 fish from
our facility and they’re all PIT-tagged so we know that at least a few of them
are growing and doing well out in Lake Michigan.”
|
Passive integrated transponder, or PIT, tags identify individual fish with a code that can be read by passing a reader over the implanted tag.
"The first year we released three fish from our facility,”
Jerome said. “The last few years have been good for us.
“Sturgeon is a clan animal to the tribe. It was believed
that if we could bring back the sturgeon in a good way, it could help the
tribal culture and community. We get a couple hundred people at the release
each year, and our tribal council puts a lot of support into the project each
year.”
This spring, Little River Band staffers recaptured a
sturgeon in Manistee Lake that had been released from the streamside facility
in 2008. The fish, originally 7.3 inches long and weighing .5 pounds, had
grown to 45 inches and 28 pounds.
Jerome said he believed the fish was headed upstream to
spawn when it was captured.
The streamside rearing facilities are essentially cargo
trailers through which river water is pumped to imprint the natal stream upon
the fish.
Even getting the fish to work with is a noteworthy task.
Unlike salmon, which typically die after spawning, sturgeon are long-lived
creatures that spawn many times over the course of their lives. Fisheries
managers prefer to not even handle them to avoid posing any potential risks to
the sturgeon.
Instead, fisheries workers collect fertilized eggs or
capture larval hatchlings with drift nets. They install egg mats in the streams
where eggs are laid – essentially concrete blocks covered with
furnace filters – to which the eggs adhere so they can be gathered and hatched
in the streamside rearing facility.
|
But not all streams have enough sturgeon in them to make
egg-collecting viable.
“The Kalamazoo, Manistee and Black rivers are rebuilding
populations,” Baker said. “The other facilities are efforts to return sturgeon
to rivers that historically had them but don’t any more. The Kalamazoo,
Manistee and Black are using locally hatched fish. The other rivers are getting
eggs from nearby streams.”
In the Upper Peninsula, the streamside facilities on the
Cedar and Whitefish River, which are tributaries to Lake Michigan, are getting
their eggs from the Peshtigo River in Wisconsin. The Lake Superior facility on
the Ontonagon River gets its eggs from the Sturgeon River in Baraga County.
Operating the streamside facilities is a rollercoaster
ride.
Brian Gunderman, a DNR fisheries biologist who oversees the
Kalamazoo River, says there are good years and bad years.
“Last year was a bad year; we only wound up with two fish,”
he said. “The year before that, we got off to a real good start – we got 2,000
eggs, the most we’ve ever got – but then we had some vandalism at the trailer
and we lost the majority of the eggs, and we wound up with 38.”
“In 2011, our first year, we got more than 100,” Gunderman
said. “It was our best year and we released 8- or 9-inch fish. But the next
year we raised none.”
The DNR has built a spawning riffle – which is a rough-bottomed, shallow section of rippling stream where fish lay their eggs –
on the Kalamazoo to attract fish to a historic spawning site, but last year few
adults showed up, Gunderman said.
Sturgeon spawn in moving water over rocky river bottom in
late April or early May, and the young are reared in the facility until August.
Survival is good if the young sturgeon are 6 inches or longer when they are
released. All are implanted with PIT tags so they can be monitored.
“We know they are surviving and growing,” Baker said. “Some
have been recaptured, and they appear to be doing very well.”
Whether the
streamside facilities will bear the desired fruit remains to be seen, Baker
said.
|
“The ultimate measure of success is whether we’re able to
establish self-sustaining populations in these rivers,” he said. “We haven’t
been at it long enough to know. It takes female sturgeon 20 to 25 years to
become mature, so we’ve got a few more years before we’ll know."
Baker said the ultimate goal is to restore lake sturgeon,
recovering their population, so they can be removed from the threatened species
list, and to then hopefully develop recreational fishing opportunities over
time.
“It’s
something that’s probably not going to happen until well after I’m retired, but
it’s exciting nonetheless,” Baker continued. “It’s happening in a lot of places
and among a lot of agencies – it really is a multi-agency, collaborative
effort.”
Get more information on
Michigan’s lake sturgeon and management of this unique species at www.michigan.gov/sturgeon.
Check out
previous Showcasing the DNR stories in our archive at www.mi.gov/dnrstories To subscribe to upcoming Showcasing articles
sign-up for free email delivery at www.michigan.gov/dnr.
|
/Note to editors: Media contact: John Pepin, 906-226-1352. Accompanying photos are available below for download. Caption information follows. Credit Michigan Department of Natural Resources, unless otherwise noted.
Both: A
look at the top and under sides of a young lake sturgeon.
Clip: A
fin is clipped before Lake Sturgeon are released.
Close: A
white color variation lake sturgeon is seen close-up.
Hand: A
lake sturgeon with typical coloring is seen close at hand.
Mats:
Sturgeon researchers working with egg mats on the Kalamazoo River below Allegan
Dam.
Pour: Pat LaPointe, a fisheries technician for the Keweenaw Bay Indian Community's Natural Resources Department pours young lake sturgeon into a holding
truck to be released in the Ontonagon River nearby.
Ready:
Lake sturgeon being dumped from a net into a bucket, just prior to their
release.
Reading:
A researcher runs a passive integrated transponder, or PIT, tag reader over a fish to identify
the individual and exactly where it came from.
Tag: A
young sturgeon is implanted with a passive integrated transponder, or PIT, tag, which can allow researchers to identify individual fish.
Trailer:
A lake sturgeon rearing trailer alongside the Ontonagon River in the western
Upper Peninsula.
Release:
Ed Baker, Michigan Department of Natural Resources research biologist, releases
lake sturgeon into the Ontonagon River.
Whitefish:
Ed Baker, Michigan Department of Natural Resources research biologist, releases
lake sturgeon into the Whitefish River in Delta County./
|