Kootenay
River White Sturgeon: Key Facts
--The white sturgeon population
of the Kootenay River (known
as the Kootenai River within
the United States) is
one of 18 landlocked populations
of white sturgeon in the Pacific
Northwest.
--There are 5 species
of sturgeon in Canadian waters,
including lake sturgeon,
Atlantic sturgeon, green sturgeon,
shortnose sturgeon
and white sturgeon.
--White sturgeon are distinguished
from other sturgeon species
by the specific arrangement
and number of “scutes”
(bony plates) along their bodies.
All sturgeon species are slow-growing.
They have long, almost scaleless
bodies, supported by
a cartilaginous skeleton,
whisker-like “barbels”
and long, shark-like
tails. They are an
ancient species, with a fossil
record dating back 100
million years.
--The white sturgeon is the
largest North American
freshwater fish; it
can weigh up to 800 kilograms!
The Kootenay Lake record is
350 kilograms (estimated at
85 – 90 years of age).
--The Kootenay River white sturgeon
is a genetically unique
strain of white sturgeon,
native only to the Kootenay
River drainage of British Columbia,
Montana and Idaho. The natural
barrier of Bonnington Falls
near Nelson, British Columbia,
a legacy of the last ice age,
has geographically isolated
the Kootenay River sturgeon
from stocks of the lower Columbia
River system.
--Sonic tracking studies show
that some sturgeon divide their
time between Kootenay
Lake and the Kootenay
River, making extended
upstream migrations of up to
114 kilometres to spawn, while
others remain in the Kootenay
River year-round.
--The entire range of the sturgeon
is thought to be about 270
kilometres, from Kootenai
Falls, Montana to the
Cora Linn Dam
at the outflow of Kootenay Lake,
with most fish concentrated
in the stretch below Bonner’s
Ferry, Idaho.
--The current wild population
of Kootenay River sturgeon is
estimated at 800 –
1500, comprised mainly
of adults over 25 years
of age. Only 1% of
the wild population is thought
to be juvenile. It is thought
that the sturgeon have not successfully
reproduced since the construction
of the Libby Dam in Montana
in 1974.
--The Kootenay River white sturgeon
population has been in decline
since the mid-1960’s.
--Current conservations
efforts in Canada and
the U.S. are attempting to boost
the sturgeon population by restoring
appropriate water flows
for spawning, and supplementing
the wild population by stocking
of hatchery-raised juveniles.
--Historically, the Kootenay
River stock supported commercial
and recreational fisheries,
and a subsistence fishery
for First Nations.
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Saving
the Kootenay River White Sturgeon
First, the
good news: Kootenay Lake still has a small
population of native white sturgeon, North
America’s largest freshwater fish.
Next, the bad news: almost the entire population
is over 25 years old, with no young sturgeon
to replenish the stock.
And finally, more good news: Canadian and
American fisheries stakeholders are joining
together in an effort to restore the white
sturgeon stocks of the Kootenay River system.
How did Kootenay Lake and the Kootenay
River that feeds it become a geriatric retirement
home for sturgeon? The answer lies in man-made
alterations to the Kootenay River watershed,
including pollution, nutrient decline, habitat
loss from bank stabilization projects and
water flow changes caused by dyking and
hydroelectric dams.
The major culprit in the decline of the
Kootenay River white sturgeon – a
genetically distinct strain of sturgeon
found only in the Kootenay River and Kootenay
Lake – appears to be the Libby Dam,
constructed on the Kootenay (Kootenai) River
in Montana in 1974. Water flow regulation
associated with the hydroelectric facility
has changed the natural flooding pattern
of the river, reducing the spring “freshet”,
or high water level, that is needed to maintain
a clean cobble bottom suitable for spawning.
Without the high water flows, siltation
occurs and the sturgeons’ eggs are
suffocated by sediment.
The result? Very few sturgeon – only
about 1% of the current Kootenay River/Kootenay
Lake population of 800 to 1500 are under
25 years of age. Most of the existing sturgeon
were produced before the Libby Dam went
into operation. Since most fish of spawning
age (about 15 – 35 years old) have
not been able to successfully reproduce,
the wild sturgeon population will continue
to age, becoming extinct as the last of
the sturgeon die within 30 – 40 years.
In order to prevent sturgeon extinction,
a joint Canadian – U.S. sturgeon recovery
team is attempting to rebuild the age-class
structure of the population. The team is
focusing on 2 remedies as part of its 10-year
white sturgeon recovery plan:
• Juvenile Stocking
- Hatchery-raised juvenile are being released
to the Kootenay River system. Young sturgeon
are being reared at the Kootenai Tribal
Hatchery in Bonners Ferry, Idaho, with a
“fail-safe” stock maintained
at the “back-up” Kootenay Sturgeon
Conservation Hatchery, on the site of the
Kootenay Trout Hatchery at Fort Steele,
British Columbia. The released fish carry
an internal tag that allows scientists to
track their survival, growth and migration
patterns.
• Water Flow Adjustment
- The recovery team is also working
with Kootenay River dam managers to adjust
water releases in accordance with the spawning
requirements of the sturgeon. Some conservation
groups, dissatisfied with the extent of
water flow adjustment and the degree of
sturgeon habitat restoration, have called
for the decommissioning of the Libby Dam
in Montana.
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