Are Kootenai River White Sturgeon Bad Parents or Have We Just Messed Up Their Habitat?

Bonners Ferry, IDflood of 1962

Libby Damflood control& hydropower1972

White sturgeonare recruitment limited by 1978

Kootenai River White Sturgeonlisted as Endangered September 6, 1994

Kootenai River white sturgeonrecovery team formedRecovery Plan crafted1) Mitigated spring flows 2) Conservation aquaculture

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Flo

w (

m3/

s)Mitigated flowsrestore someof the spring freshetPre-Libby Dam

Post- Libby Dam

57,000 cfs

28,251 cfs

1990s – Instream Flow IncrementalMethodology -Habitat Assessment

1991-1993 STURGEON ShouldBe Spawning at Bonners FerryOr Upstream (best habitat)(some eggs found) ???

1994 – 2009 STURGEONPrimarily spawning from Shorty’s to the Refuge

Kootenai River white sturgeon have a short two stepMigration pattern

From Kootenay Lake

To Staging reach

To several spawning locations

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B onners Ferry

K ootenay L ake

K ootenai Falls

L ibby Dam

British C o lum b ia

Id a ho M o nta na L akeK ooc anusa

Des igna tedC rit ic a lH ab ita t

B onnington Falls(inundated)

2001

Early life history

sturgeon eggs are adhesiveand need cobble or gravel substrate

to ensure best survival

White sturgeon spawn within a 12 mile reach but survival bottleneck impairs recovery!

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Dep

th, i

n m

e ter

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Sturgeon are spawning over moving sand dunes!

Suitable substrate includesCobble and gravel – not sand!

Present spawning location

Above Bonners Ferry there is better habitat!

B onners Ferry

K ootenay L ake

K ootenai Falls

L ibby Dam

British C o lum b ia

Id a ho M o nta na L akeK ooc anusa

Des igna tedC rit ic a lH ab ita t

B onnington Falls(inundated)

Critical Habitat extended

2001

Why are they spawning over unsuitableHABITAT ?

Two lines of thought as to why there is poor spawning success

1. White sturgeon migration is impaired and not going further upstream above Bonners Ferry where thereis good cobbles and faster currents than the present spawning location – good habitat!

2. White sturgeon are spawning in the historic locationbut post Libby Dam habitat changes have prohibited survival !

Why aren’t white sturgeon spawning in better habitat?

Idaho Department of Fish and Game and Kootenai Tribe of Idaho Team

and experiment with translocation of spawning adults

B onners Ferry

K ootenay L ake

K ootenai Falls

L ibby Dam

British C o lum b ia

Id a ho M o nta na L akeK ooc anusa

Des igna tedC rit ic a lH ab ita t

B onnington Falls(inundated)

Movement summary 2003:

1.Number of Fish tracked: 7 moved to Hemlock Bar

2.Moved out of Hemlock Bar area: 2 M 1F

3.Stayed in the area for 1 week: 2 M 2 F

4.Spawned for sure: 1 F

5.Upstream movements: 2M 2F

6.Fish showed possibility of successful spawning but movement was almost continuous.

Movement summary 2004

1) 17 adults moved all fitted with sonicand radio tags and moved to Hemlock Bar

2) 6 females and 11 males3) Releases partitioned by early (<8 C)

and late (>8 C)4) Males moved early will stay longer than those moved late5) Females moved early have a tendency to move out sooner than females moved late6) 2004 no eggs were found but much more movement of adults.

7) Fish were very active and appeared disoriented

Second analysis

Over a five year period 70 white sturgeon were tagged with radio transmitters and movements above Bonners Ferry documented

with fixed location receivers.

1.Analysis indicated some sturgeon did move above Bonners Ferry but not far.

2.There was no interaction of movement and temperature or discharge.

3.Movement was random!

4.There are no known elements at this time to entice sturgeon upstream.

Fixed location receiver

2. White sturgeon are spawning in the historic locationbut post Libby Dam habitat changes have prohibited survival !

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1998

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River kilometer

199419951996199719981999

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ggs

Five primary spawning locations – egg collections

Idaho Department of Fish and Game and Kootenai Tribe of Idaho Team with

US Geological Survey to help resolve issue of spawning location with

1) Sediment composition and transport studies2) Bathymetry records3) Current Profiles 4) Sub-bottom substrate profiles5) All combined with egg collection data from

1994 - 2002

USGS studies are integrated with IDFGsturgeon egg collections from 1994 - 2002

Studies took place above, within, and below white sturgeon spawning

reach

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SEPUE

Egg collections associated with locations ofaccelerated velocities

regardless of dischargeDecreasing meanvelocities

Decreasing meanvelocities

Cobbles and gravels exposedWithin a present day spawning location

Sediment transport model and multidimensional Model used to simulate 1974 event for 14 days

Scouring occurs

Flood event of 2006 – 1,900 m /s (67,000 cfs) exposes cobbles and gravel substrates in a Spawning location - Validating model

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Cobbles and gravels

Important Findings

1) Once proper temperature of river reached sturgeon spawn,mitigated discharge important but not to initiate spawning

2) White sturgeon are keying on points of accelerating Velocities and deep water

3) Lack of flushing flows post Libby Dam have buried cobblesand gravels previously exposed by spring freshet

Our mitigated discharges are not sufficient to scour cobbles and gravel clean

Kootenai River white sturgeon likely spawned in the same Location pre-Libby Dam!

In lieu of increased discharge - habitat enhancement in the present spawning location is the most important measure to rehabilitate Kootenai River white sturgeon

Management Implication

Habitat

Habitat

Habitat

Habitat