Springtime is busy at the Dworshak Hatchery. The smolts have left via truck and forced
release into the Clearwater river and its tributaries. They will ride the spring freshet (high
water) down the Clearwater river and into the Snake River system. Once in the Snake, they will first encounter
Lower Granite Dam. Many of the smolts
will be trapped in the smolt bypass system and loaded onto barges for the
remaining trip down the Snake and Columbia Rivers. Some of the smolts are PIT tagged and released
back into the hydro system to evaluate the effects of barging.
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Crowded steelhead smolts await release |
On the Hatchery, releasing fish is a one to two week process
in early April. Chinook salmon smolts
are generally released onsite, called “direct release”, into the North Fork
Clearwater River. The fish are forced out
of the raceways with crowding screens rather than volitionally released (leave
on their own accord). This process
generally takes one to two days. The
hatchery crew releases the smolts in the evening hours when the light levels
are low and the seagulls are less apt to spot the young fish. This strategy gives the young fish the cover
of darkness to disperse from the hatchery and avoid initial predation.
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Crowding steelhead smolts to the release channel |
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Steelhead smolts "direct released" to the Clearwater River |
About half, 1.2 million, of Dworshak’s steelhead smolts are
direct released into the Clearwater river.
The steelhead smolts are significantly bigger than the Chinook salmon
smolts (8 inches versus 5 inches), and suffer less bird predation. The direct release smolts are also forced out
with crowders, but are allowed to volitionally release from the transfer
channels. Most of the steelhead swim out
quickly, within 1 to 2 days after being forced from the Burrows Ponds.
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Getting ready to pump steelhead onto on "off-site" release truck |
The
remaining steelhead smolts, 1 million, are transported by semi-tanker trucks to
offsite release areas in the South Fork of the Clearwater River. These releases provide fisheries and
restoration benefits in the upper reaches of the South Fork. The smolts are sucked onto the trucks with
large fish pumps. These pumps are
specially designed not to damage the young fish when they traverse through the
pump impeller. Once in the transport
tanks, the smolts are provided with oxygen and aeration for their trip to the
release sites. The transport times vary
between 1 to 2 hours. Once at the
release sites, the fish are released through a large release tube – much like a
waterslide for fish!
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Releasing steelhead smolts from the transport truck |
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Whee!!!! |
by Nate Wiese
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