Salmon & Steelhead Recovery Tracker

Lower Umpqua (Independent Population)

Analyses of viability criteria (adult abundance, persistence, productivity, distribution, diversity and habitat) are presented for each independent population. Trends in adult abundance and habitat condition are presented for dependent populations.

Oncorhynchus kisutch

Abundance

Annual estimates of the abundance of naturally-produced spawners for each population.

Spawning Year Nat. Origin Spawners 95% Confidence Interval Abundance Goal Proportion of Goal
2016 4,422 1,049 56,600 8.0%
2015 3,725 2,069 29,400 13.0%
2014 36,942 11,465 64,700 57.0%
2013 7,792 2,653 56,600 14.0%
2012 3,731 1,277 56,600 7.0%
2011 18,715 6,132 64,700 29.0%
2010 17,516 4,872 64,700 27.0%
2009 19,245 5,346 64,700 30.0%
2008 9,023 2,231 56,600 16.0%
2007 4,237 1,411 29,400 14.0%
2006 7,994 3,752
2005 18,591 6,401
2004 8,989 2,248
2003 16,494
2002 18,881
2001 11,639
2000 5,781
1999 2,623
1998 4,552
1997 1,257
1996 7,985
1995 10,854
1994 2,762

Evaluation Thresholds

Pass -the observed spawner abundance is > the marine survival-specific escapement target at least six times in any 12-year period.

Fail - the observed spawner abundance is > the marine survival-specific escapement target 5 times or less in any 12-year period.

Distribution

The manner in which adults (spawners) are distributed within the freshwater portion of a population's home range.

Metrics

1. The percentage of random, spatially balanced surveys that have more than 4 wild adult spawners/mile (percent occupancy)

2. Comparison of the spatial pattern of potential spawning distribution to that observed using SVB or other spatial statistics.

Spawning Year Sites Occupied Sites Total Percent Occupied Occupancy Goal
2016 12 15 80% 90%
2015 11 18 61% 90%
2014 15 18 83% 90%
2013 22 30 73% 90%
2012 16 27 59% 90%
2011 21 25 84% 90%
2010 26 27 96% 90%
2009 22 28 79% 90%
2008 11 12 92% 90%
2007 29 51 57% 90%
2006 30 42 71%
2005 24 29 83%
2004 49 53 92%
2003 42 48 88%
2002 49 52 94%
2001 41 47 87%
2000 28 44 64%
1999 18 36 50%
1998 18 29 62%

Evaluation Thresholds

Metric 1

Pass - the observed percent occupancy is greater than or equal to the marine survival-specific occupancy target at least six times in any 12-year period.

Fail - the observed percent occupancy is greater than or equal to the marine survival-specific occupancy target five times or less in any 12-year period.

Metric 2

Pass - the observed regularity ratio is not significantly different from a random distribution at least six times in any 12-year period.

Fail - the observed regularity ratio is significantly different from a random distribution at least six times in any 12-year period.

Diversity
  • 2007
    pass

Within-population diversity is the result of phenotypic differences among individuals. These differences provide the flexibility of the population as a whole to respond successfully to short-term environmental variations. They are also the basis by which populations are able to adapt and evolve as conditions within their home range go through changes that are more permanent.

Metric

The average of the 100-year harmonic mean of spawner abundance for each independent population, as forecast from a population viability model.

Analysis Year Harmonic Mean Goal
2007 10,219 1,200

Evaluation Thresholds

Pass - If 100-year harmonic mean of spawner abundance is greater than 1,200.

Fail - If 100-year harmonic mean of spawner abundance is less than or equal to 1,200.

Time Period Category Comment
2007 pass Goal met 1 of 1 years

Habitat
  • 2011
    fail

The amount of available high quality habitat for all freshwater life stages in each independent population, excluding the lakes populations.

Habitat condition is evaluated using population specific winter habitat surveys in the range of coho salmon. These surveys began in 2007 with the goal of surveying each independent population or dependent population group once every 5 years. Not all populations in the Coast Coho ESU have been surveyed for habitat at this time therefore some populations will display no habitat data.

Survey Year Miles Current 95% Confidence Interval Miles Goal Percent of Goal
2011 63.2 61.4 306 20.7%

Evaluation Thresholds

For a population to pass this criterion, the miles of high quality habitat (i.e. capable of producing > 2,800 smolts/mile) equals or exceeds the population-specific goals.

Time Period Category Comment
2011 fail Goal met 0 of 1 years

Persistence
  • 2007
    pass

The forecast probability of persistence for each independent population based on results from population viability analysis (PVA) models.

Analysis Year Average Probability Goal
2007 0.993 0.99

Discussion and Rationale

A persistence criterion of a 99% or greater probability of persistence significantly increases the likelihood that the ESU will remain viable under extreme marine survival conditions while providing substantial environmental, cultural, and economic benefits. Future analyses will be based on an average persistence value from the four PVA models developed by the TRT (Wainwright et al. 2008;Wainwright et al. 2006 poster).

Analysis

Because of the uncertainty of demographic effects at low population size, the TRT used two levels of "quasi-extinction" (1 and 50) to model persistence of the populations.

Evaluation Thresholds

For a population to pass this criterion it must have an average probability of persistence of 0.99 or greater as estimated by the four PVA models used by the TRT (Wainwright et al. 2008;Wainwright et al. 2006 poster).

Time Period Category Comment
2007 pass Goal met 1 of 1 years

Productivity

Annual estimates of the number of naturally produced recruits (progeny) per spawner (parent) (R/S) in the population.

Spawning Year R/S
2016 0.62
2015 1.22
2014 2.26
2013 0.52
2012 0.23
2011 2.11
2010 3.90
2009 2.14
2008 0.48
2007 0.53
2006 0.52
2005 0.98
2004 0.76
2003 3.04
2002 7.33
2001 2.65
2000 4.18
1999 0.34
1998 0.45
1997 0.47

Evaluation Thresholds

Pass - Over a 12-year period, R/S values, standardized to a spawner density equal to the spawner abundance goal for each marine survival category, are statistically greater than or equal to 1.0.

Fail - Over a 12-year period R/S values, standardized to a spawner density equal to the spawner abundance goal for each marine survival category, are statistically less than 1.0.