| Year | Accomplishment |
|---|
| 1997 |
This was the first year of the project. The U.S. Army Corps of Engineers successfully changed the winter lake levels which added 1.8 million square feet of spawning gravel to the lake. |
| 1997 |
Kokanee fry survival was measured but did not improve. This was also bad flood year ; a 100 year event. |
| 1997 |
Three University of Idaho projects were started. |
| 1997 |
Kokanee population was successfully measured by hydroacoustics, trawling and spawner counts. |
| 1997 |
Kokanee spawning activity was mapped on 100 miles of shoreline. Kokanee were documented to have moved into new shoreline areas for spawning. |
| 1997 |
Depths of kokanee spawning were measured. Kokanee were found to have moved on to newly available gravel at shallower depths which should improve rearing success. |
| 1997 |
Shrimp population was successfully measured by random sampling in three sections of the lake and was numerically stable. A stable shrimp population will benefit the experiment. |
| 1998 |
Kokanee population successfully measured by trawling and hydroacoustics. Fry abundance was very low. |
| 1998 |
Graduate student study successfully shows that newly emerged kokanee do not starve because of competition with Mysis shrimp. Study also shows that food was not limiting for kokanee in 1998. |
| 1998 |
Extensive sampling of shoreline spawning gravel shows very little siltation due to changing lake levels during the first two years. |
| 1998 |
Higher lake levels during the winter of 1997-98 may have contributed to higher egg-to-fry survival rate of 9.9% (up from 1.4% in 1995). |
| 1999 |
Higher lake levels during the winter of 1998-99 may have contributed to higher egg-to-fry survival rate of 6.0% (up from 1.4% in 1995), but questions were raised about compensatory responses of the low kokanee population. |
| 1999 |
Graduate study on predation estimates 114 tons of kokanee are eaten per year from the lake. This was not a problem in 1996 but may have contributed to kokanee declines in 1999. |
| 1999 |
Shrimp population in lake was successfully measured for fifth straight year and was found to be stable even though kokanee numbers declined. Shrimp abundance appears to be controlled from below (primary production) not above (by predation). |
| 1999 |
Shrimp sampling conducted with both vertical net tows and a high speed Miller sampler. Density estimates can now be inter-converted between the two methodologies. |
| 1999 |
Gravel sampling on shoreline areas shows strong movements in shoreline gravel. This indicates the need for lower lake levels approximately once ever 4 years to move gravel to lower pool level. |
| 1999 |
Graduate study on the Pend Oreille River shows importance of over-winter habitat to the warm-water fish populations. Study is still in progress. |
| 1999 |
Kokanee population successfully measured by hydroacoustics. Hydroacoustics yielded population estimates with 90% confidence limits of + or - 9% for fry and 17.8% for 1 to 5 year olds. |
| 1999 |
Kokanee population successfully measured by mid-water trawling. Trawl estimates yielded population estimates with 90% confidence limits of + or - 28% to 64% for different age classes. Older age classes found to be declining. |
| Objective | Task | Duration in FYs | Estimated 2001 cost | Subcontractor |
|---|
| 1.Recover kokanee abundance so that a harvest of 750,000 fish can be maintained on an annual basis. This would require an adult kokanee population of 3.7 million fish. |
a. U.S. Army Corps of Engineers raises the lake level 4 feet during the winter of 1996-97, 1997-98, and 1998-99. |
3 |
$0 |
|
| 2.Sub-objective: determine if adult kokanee population reaches 3.7 million and determine if egg to fry survival exceeds 3.6%. |
a. Conduct mid-water trawling in the lake to determine population estimates, biomass, age, and size of kokanee. Estimate number of eggs being laid. |
5 |
$38,000 |
|
| 3. Sub-objective: verify the accuracy of trawling and determine its net efficiencies. |
a. Conduct mobile hydroacoustic surveys to estimate age classes of kokanee and compare to trawl data. |
5 |
$38,000 |
|
| 4.Sub-objective: determine trend of lake levels to kokanee population and its statistical significance. |
a. Compare kokanee population to past data and relate to changes in lake level using multiple regression analysis. |
5 |
$1,000 |
|
| 5. Sub-objective: use spawning kokanee abundance as a surrogate index of adults, look for a doubling of spawning fish. |
a. Conduct spawner counts of kokanee along shoreline and relate to past data. |
5 |
$20,000 |
|
| 6. Sub-objective: determine if egg to fry survival exceeds 3.6 %. |
Calculate survival rates of kokanee and determine if lake level changes cause changes in survival. |
5 |
$1,000 |
|
| 7. Sub-objective: determine if kokanee pioneer new areas to reduce intra-specific competition of fry and determine if kokanee use the cleaner newly created gravel to improve survival. |
a. Map location and depth of kokanee spawning along 100+ miles of shoreline. |
3 |
$30,000 |
|
| 8. Sub-objective: try in-situ experiments to estimate improvement in egg to fry survival. |
a. Place kokanee eggs in Vibert type boxes and bury in the shoreline substrates of different qualities to determine changes in incubation with changed lake levels. |
1 |
$0 |
|
| 9. Sub-objective: determine changes in wild fry survival without masking the effect by stocking hatchery fish. |
a. Cold-brand the otoliths of all hatchery produced fry that are stocked into the lake. Read otoliths to separate wild and hatchery fish. |
5 |
$15,000 |
Yes |
| 10. Sub-objective: provide a diagrammatic over-view of the relationships within the lake, as per Power Planning Council's request. |
a. Build a systems model (not a computer model) of the lake as well as a sensitivity analysis of the state variables and feedback loops to show determinants of recruitment and survivorship. |
1 |
$18,000 |
|
| 11. Have no net change in the amount of shoreline spawning gravel due to erosion or siltation during this experiment (maintain 1.7 million sq. feet). |
a. Monitor the quality of shoreline gravel by scuba diving and analyzing the silt, sand, gravel, and cobble content. |
4 |
$45,000 |
|
| 12. Increase the warm water fish population in the Pend Oreille River seven fold. |
a. Change the winter elevation of the river 4 feet. (This task is being done by the U.S. Army Corps.) |
3 |
$0 |
|
|
b. Monitor warm water fish populations in the Pend Oreille River by gillnetting , seining, and electrofishing and compare to data collected in 1991 and 1992. |
3 |
$30,000 |
Yes |
|
c. Determine year class strength and over winter mortality of fish produced with changed river levels. |
3 |
$20,000 |
Yes |
| 13. Determine whether other factors could be limiting the kokanee population by either competition or predation. |
a. Build a year-round energy budget model for the lake including zooplankton, shrimp, kokanee, and predators. |
2 |
$65,000 |
Yes |
|
b. Make population estimate of kokanee predators using hydroacoustics. |
2 |
$20,000 |
|
|
b. Monitor zooplankton weekly during spring and fall and monthly the remainder of the year. |
2 |
$0 |
Yes |
|
c. Sample shrimp annually to determine density and abundance. |
5 |
$30,000 |
|
|
d. Estimate predator abundance using mark and recapture methodology. |
3 |
$0 |
Yes |
|
e. Electro-fish shorelines to define impact of near shore predators. |
2 |
$0 |
Yes |
|
f. Calculate consumption of predators using bioenergetics and incorporate into energy model. |
2 |
$0 |
Yes |
|
g. Survival of wild fry will be correlated to hatchery stocking to determine potential impact of hatchery fish. |
1 |
$1,000 |
|
| 14. Keep Eurasian milfoil from becoming a significant problem in Lake Pend Oreille |
a. Conduct a literature review of the life history of milfoil. |
4 |
$0 |
Yes |
|
b. Map areas of the lake that are milfoil habitat. |
4 |
$0 |
Yes |
|
c. Search for milfoil along 100+ miles of shoreline. |
4 |
$0 |
Yes |
|
d. Determine limnology at location of milfoil sites. |
4 |
$0 |
Yes |
|
e. Design site-specific management recommendations. |
4 |
$0 |
Yes |
|
f. Document plant community response during years of deeper drawdown. |
4 |
$0 |
Yes |
| 15. Determine any large impact of changed lake levels on riparian vegetation and waterfowl as per Councils request. |
a. Photo documentation of representative shoreline vegetation will be made during and after years of high water. |
3 |
$8,000 |
|
|
b. An annual waterfowl count will be made from a fixed wing aircraft. |
5 |
$0 |
|
This information was not provided on the original proposals, but was generated during the review process.