Tip:
Highlight text to annotate it
X
The lake sturgeon is one of the largest
freshwater fish species in North America.
Though once abundant in the Great Lakes,
unsustainable commercial harvesting of lake sturgeon
beginning in the mid-1800s led to a steep
decline in their populations by the early 20th century.
Lake sturgeon are, as many people realize,
one of the oldest species of fish that
remain in the Great Lakes.
They are a relic.
They date back to the era of the dinosaurs,
similar to tortoises, alligators and sharks.
It has only been in the last 100 years
that populations in the Great Lakes have
become severely depleted.
What used to be millions of sturgeon in Lake Michigan
is now down to less than 5,000.
That is a significant decline
and there have not been significant signs
of recovery over the past 50 years.
A number of populations have been increasing,
but increasing very slowly.
Then there are a few populations that,
like the one here on the Kalamazoo,
that are at such critically low abundance
that we are fearful that if left
unassisted they might disappear.
When lake sturgeon populations are depleted,
it is difficult for them to recover quickly
even under ideal environmental conditions,
because their reproductive cycle is slow.
Female lake sturgeons do not reach *** maturity
maturity until they are over 20 years old
males mature earlier, approximately 15-20 years.
Like most fish species,
the survival rate of very young
lake sturgeon is also poor.
In the wild, lake sturgeon eggs
and larvae are vulnerable to predation
disease, pollution and starvation.
As a part of a multi-agency effort
to rehabilitate lake sturgeon
in Lake Michigan
the U.S. Fish and Wildlife Service has built
and currently operates a
streamside rearing unit on
cooperatively with the Michigan Department of Natural Resources
on the Kalamazoo River in Michigan.
The streamside rearing unit,
built from a retro-fitted trailer,
protects young sturgeon from
environmental stressors that can
threaten them in their first months of life.
An important component to the
streamside rearing unit is that
the young fish are reared in water
pumped from the Kalamazoo River.
This increases the likelihood that
the young sturgeon will “imprint” to the river
as their natal waters in the
same way wild raised lake sturgeon do.
The hope is that after being
released into the wild, the lake sturgeon
will return to the Kalamazoo River in
15 to 25 years when they are ready to spawn.
One of the things that we have
at Genoa National Fish Hatchery
that we do not have on a
streamside rearing unit
is we are able to filter,
disinfect and use very clean well water
from a groundwater source.
When you go out onto a streamside rearing unit,
you have variations in not only temperature,
but also the clarity of the water,
the turbidity of the water,
how much sediment is carried in that water.
If it is a really heavy sediment load,
then there is the possibility that it
might affect the fishes’ health negatively;
it would get in their gills and irritate them.
Then a bacterial infection may occur.
So what we try to do is not only disinfect the
water with ultraviolet disinfection method,
water with ultraviolet disinfection method,
but also to filter out the really heavy sediment
load so it is not a negative factor
affecting the fishes’ health.
One of the interesting characteristics
of this facility, as is true for the Manistee River Facility,
is it is not a stocking introduction to
bring sturgeon back into the river
where they have been extirpated. It is an assistance
where they have been extirpated. It is an assistance
of a naturally spawning population.
So there are wild sturgeon that
spawn in the Kalamazoo River.
So the young sturgeon that are being
reared in this trailer are actually coming
from eggs and larval sturgeon that
we collected in the spring from
wild spawning fish.
The streamside rearing unit was
made possible by the support of
numerous project partners.
Naturally fertilized eggs were collected
for the streamside rearing unit from the
Kalamazoo River in April and May
by a team of biologists from the
Michigan Department of Natural Resources,
, the Match-e-be-nash-she-wish Band of Pottawatomi Indians
and the U.S. Fish and Wildlife Service’s
Green Bay Fish and Wildlife Conservation Office
and Genoa National Fish Hatchery,
with assistance from the Kalamazoo River
Chapter of Sturgeon for Tomorrow.
Together they collected several hundred
fertilized eggs from the river.
Once placed into the streamside rearing unit,
the wild eggs soon hatched.
Over the next six months U.S. Fish and Wildlife Service
and Michigan Department of Natural Resources staff
nurtured the young sturgeon,
feeding them brine shrimp, blood worms, and krill.
By September the young lake sturgeon are
between six to ten inches in length,
and ready to be tagged and released
into the Kalamazoo River.
In its inaugural year, 106 fingerling sturgeon raised in the streamside rearing unit
were released back into the Kalamazoo
River during a release event attended by over 500 people.
The Allegan County Parks Commission
provided space at the New Richmond Bridge Park
in Allegan County for the
streamside rearing unit to be placed.
If you find yourself in Michigan during the summer,
we welcome you to visit the streamside rearing unit.
If a staff member is on-site,
we will gladly let you take a look at
the young lake sturgeon and answer your questions.
Working with lake sturgeon for the
past twenty years, it is a
really fascinating fish.
It is a really unique fish,
not only in the culture of it,
but also just to know that
the work you are doing today
will carry on for over 100 years
if the fish survives.
So you have a real chance
to impact the next generation.
That is a good feeling to
know that your work will
carry on way past you.
The Kalamazoo River streamside rearing unit
was funded in part by the
Great Lakes Restoration Initiative.
For more information,
please visit the U.S. Fish and Wildlife Service’s
Great Lakes Restoration Initiative website.