1 Independent Scientific Advisory Board June 12, 2003 A Review of Salmon and Steelhead Supplementation

2 Supplementation 1 is an artificial production strategy to increase abundance of a natural population, while maintaining fitness of the natural population and limiting ecological impacts on non-target species 1 RASP (1992) time Salmon Abundance

3 Conventional Strategy - Segregated Population Natural Population Hatchery Population Conventional Artificial Production vs. Supplementation Natural-origin smolts Natural-origin adults Common Migration and Marine Environments Mixture of hatchery-origin and natural-origin fish Hatchery-origin smolts Hatchery-origin adults Hatchery Strays

4 Supplementation Strategy - Integregated Population Natural Population Hatchery Population Conventional Artificial Production vs. Supplementation Natural-origin smolts Natural-origin adults Common Migration and Marine Environments Mixture of hatchery- origin and natural-origin fish Hatchery-origin smolts Hatchery-origin adults Natural-origin adults

5 Requires females spawning in a hatchery to exceed the productivity of females spawning naturally Hatchery Productivity (R a ) Natural Productivity (R w )

6 Requires reproduction of hatchery-origin adults in the wild Hatchery Component Natural Component N = 5 N = 6 N = 7 T0T0 T1T1 T2T2

7 Uncertainties Habitat: Genetic/Evolutionary: Demographic: The question still remains, is supplementation effective?

8 NOAA request: Consider the benefits and risks of supplementation to natural populations of salmon and steelhead. Council request: Can artificial and natural production be integrated to increase the capacity and productivity of the combined population over the foreseeable future.

9 The ISAB Investigated:  Ecological and Genetic Theory Applied to Supplementation  Columbia River Basin Supplementation Experiments  Supplementation Risk-benefit Assessment Tools

10 Genetic Theory: Genetic risks to a natural populations Natural Population Gene Pool Domestication Selection Adaptation to hatchery spawning, rearing, and release Inbreeding Depression small founding numbers produce large numbers of related individuals Outbreeding Depression horse x donkey = sterile mule fall x spring chinook = ?

11 Genetic Theory: Domestication Selection-Adaptation to a Hatchery Environment Selection is a consequence of the differential survival (production) of adults by different families Differential success of reproduction in Forks Hatchery steelhead Differential reproduction can be large among hatchery- spawned families providing the opportunity for domestication selection

12 Ecological Theory: Any benefit to population abundance depends on: Intrinsic biological parameters of the stock in its environment  Productivity of the hatchery (R a ) and natural (R w ) spawners Policy constraints and management control variables  Broodstock mining rate  Proportion of natural population that consists of hatchery-origin adults  Harvest rate  Harvest selectivity

13 Ecological Theory: Conclusions from Modeling  Ongoing supplementation can be expected to increase the number of naturally spawning salmon and the potential for harvest.  The increased population size and productivity attributable to supplementation will likely not persist once supplementation ceases.  Supplementation can reduce natural spawning fitness which will persist for some number of generations after the termination of supplementation.  Natural spawning fitness can decrease with increases in the broodstock mining rate, the harvest rate, and in the proportion of hatchery-origin versus natural-origin adults taken for broodstock.

14 Quantifying Benefits and Risks: Performance indicators and standards Abundance: Abundance of Natural-Origin Adults Abundance of Hatchery-Origin Adults Productivity: Replacement rate of Natural spawning (R w ) Replacement rate of Hatchery spawning (R a ) Long-term Fitness: R w after supplementation ceases

15 Quantifying Benefits and Risks: Performance indicators and standards - Adult Abundance Natural-origin and hatchery-origin adult abundance is required to confirm that hatchery-origin adults are “adding to”, not replacing or substituting for, natural- origin adults. Natural Adults Hatchery Adults Natural Adults Demographically Successful Supplementation Unsuccessful Supplementation Total Adults

16 Quantifying Benefits and Risks: Performance indicators and standards - Reference Streams The challenge to quantifying supplementation effects is detecting treatment effects against a background of high natural variability Productivity Variation in Oregon Steelhead

17 Reference sites are required to distinguish effects of supplementation from local background variation and out-of-basin effects. Quantifying Benefits and Risks: Performance indicators and standards - Reference Streams

18 Quantifying Benefits and Risks: Performance indicators and standards - Reference Streams Judging Supplementation as a Success or Failure? Supplemented Natural spawning adults of natural origin Supplemented Natural spawning adults of natural origin

19 Quantifying Benefits and Risks: Performance indicators and standards - Reference Streams Demographically Successful Supplementation Supplemented Reference Natural spawning adults of natural origin Supplemented Reference Unsuccessful Supplementation Natural spawning adults of natural origin Quantifying Benefits and Risks: Performance indicators and standards - Reference Streams Judging Supplementation as a Success or Failure?

20 Quantifying Benefits and Risks: Performance indicators and standards - Cohort Analysis Estimating population statistics is difficult because salmon and steelhead have very complex life-histories. Brood Year Return Year 12 3

21 Assessing Columbia River Basin Supplementation Experiments Projects: 1. Hood River winter-run steelhead 2. Umatilla River summer-run steelhead 3. Yakima River spring-run chinook 4. Wenatchee River spring-run chinook 5. Similkameen River summer-run chinook 6. Tucannon River spring-run chinook 7. Imnaha River spring-run chinook 8. Imnaha River summer-run steelhead 9. Idaho Supplementation Studies spring-run chinook

22 Assessing Columbia River Basin Supplementation Experiments What is known about supplementation and largely undisputed. A. There is a juvenile survival benefit attributable to rearing in the protected hatchery environment Egg-to-Smolt Survival Rate Hatchery Hood River winter-run steelhead68.0% Tucannon River spring-run chinook73.0% Natural Hood River winter-run steelhead 1.2% Tucannon River spring-run chinook 4.2%

23 Assessing Columbia River Basin Supplementation Experiments B. Smolt-to-adult return rates (SARs) are typically higher for natural-origin adults than for hatchery-origin adults. Smolt-to-Adult Survival Rate Hatchery Hood River winter-run steelhead0.68% Tucannon River spring-run chinook 0.22% Yakima River spring-run chinook 5.85% Natural Hood River winter-run steelhead3.80% Tucannon River spring-run chinook1.63% Yakima River spring-run chinook6.50%

24 Assessing Columbia River Basin Supplementation Experiments C. Adult replacement rate (adult recruits per spawner) is greater for hatchery than for naturally reared juveniles Adult Recruits Per Spawner Hatchery (Ra) Imnaha River spring-run chinook4.00 Tucannon River spring-run chinook 2.52 Hood River winter-run steelhead8.49 Umatilla River summer-run steelhead2.86 Natural (Rw) Imnaha River spring-run chinook0.50 Tucannon River spring-run chinook0.86 Hood River winter-run steelhead 0.94 Umatilla River summer-run steelhead0.60

25 Assessing Columbia River Basin Supplementation Experiments D. SARs for hatchery produced smolts were substantially lower than programs targets. Consequently, the yield of adult salmon and steelhead did not achieve performance standards. 1. Based on different sets of years

26 Assessing Columbia River Basin Supplementation Experiments E. Hatchery-origin adults on the spawning grounds in the late 1980s and early 1990s did not prevent declines in the abundance of natural-origin adults in the mid-1990s. Imnaha River Summer-run Steelhead

27 Assessing Columbia River Basin Supplementation Experiments E. (continued) Tucannon spring-run chinook

28 Assessing Columbia River Basin Supplementation Experiments F. Relatively large proportions of hatchery-origin adults are being used as broodfish in hatchery spawning Proportion of hatchery-origin adults used as broodfish in hatchery spawning As the proportion of hatchery-origin adults are used in hatchery spawning, projects will become increasingly more “conventional” in their management. Hatchery-origin adults from conventional production have poor natural spawning fitness.

29 Assessing Columbia River Basin Supplementation Experiments G. Stray adults from conventional hatcheries compromise experimental designs Stray hatchery chinook salmon recovered in ISS study streams in the Clearwater subbasin during carcass surveys.

30 Assessing Columbia River Basin Supplementation Experiments H. Stray adults from conventional hatcheries are producing de facto supplementation with the worst possible breeding protocol. ODFW data

31 Assessing Columbia River Basin Supplementation Experiments H. The full suite of performance indicators is available for only a few projects

32 ISAB Recommendations  Use supplementation sparingly.  Only use natural-origin adults from the target population as parents in hatchery spawning.  Establish and monitor performance standards.  Conduct all supplementation projects with explicit experimental designs.  Coordinate the multiple supplementation projects as a basinwide adaptive management experiment.  Ensure that individual projects are collecting the data necessary to test their effectiveness and ensure regional coordination of the multiple experiments.

33 NOAA Question NOAA: What are the benefits and risks of supplementation to natural populations? ISAB response: Benefit – Supplementation has the potential to forestall imminent extinction. Risk – Supplementation will cause a reduction in natural spawning fitness to the target population.

34 Council Question Council: Can production (natural and artificial) be integrated to increase productivity? ISAB response: Yes, but at some cost to the capacity of the natural population to be self-sustaining.