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

Bonners Ferry, ID flood of 1962 Libby Dam flood control & hydropower 1972 White sturgeon are recruitment limited by 1978

Mitigated flows restore some of the spring freshet Pre-Libby Dam Post- Libby Dam 57,000 cfs 28,251 cfs

1990s – Instream Flow Incremental Methodology - Habitat Assessment STURGEON Should Be Spawning at Bonners Ferry Or Upstream (best habitat) (some eggs found) ??? 1994 – 2009 STURGEON Primarily spawning from Shorty’s to the Refuge

Kootenai River white sturgeon have a short two step Migration pattern From Kootenay Lake To Staging reach To several spawning locations

Early life history sturgeon eggs are adhesive and need cobble or gravel substrate to ensure best survival

White sturgeon spawn within a 12 mile reach but survival bottleneck impairs recovery! Depth, in meters Sturgeon are spawning over moving sand dunes! Suitable substrate includes Cobble and gravel – not sand!

Present spawning location Above Bonners Ferry there is better habitat!

Critical Habitat extended 2001 Why are they spawning over unsuitable HABITAT ?

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 there is good cobbles and faster currents than the present spawning location – good habitat! 2.White sturgeon are spawning in the historic location but 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

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 )17 adults moved all fitted with sonic and radio tags and moved to Hemlock Bar 2)6 females and 11 males 3) Releases partitioned by early (<8 C) and late (>8 C) 4) Males moved early will stay longer than those moved late 5) Females moved early have a tendency to move out sooner than females moved late 6) 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 location but post Libby Dam habitat changes have prohibited survival !

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 studies 2)Bathymetry records 3)Current Profiles 4) Sub-bottom substrate profiles 5) All combined with egg collection data from

USGS studies are integrated with IDFG sturgeon egg collections from Studies took place above, within, and below white sturgeon spawning reach

Egg collections associated with locations of accelerated velocities regardless of discharge Decreasing mean velocities Decreasing mean velocities

Cobbles and gravels exposed Within 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 3 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 cobbles and 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