Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

Status and Trends
Puget Sound Chinook salmon were listed as threatened in 1999 (64 FR 14308). This
status was re-affirmed on June 28, 2005 (70 FR 37160). This ESU has lost 15 spawning
aggregations that were either demographically independent historical populations or
major components of the life history diversity of the remaining 22 existing independent
historical populations identified (Good, Waples et al. 2005). Nine of the 15 extinct
spawning aggregations were early-run type Chinook salmon (Good, Waples et al. 2005).
The disproportionate loss of early-run life history diversity represents a significant loss of
the evolutionary legacy of the historical ESU.
The estimated total run size of Chinook salmon in Puget Sound in the early 1990s was
240,000 fish, representing a loss of nearly 450,000 fish from historic numbers. During a
recent five-year period, the geometric mean of natural spawners in populations of Puget
Sound Chinook salmon ranged from 222 to just over 9,489 fish. Most populations had
natural spawners numbering in the hundreds (median recent natural escapement is 766).
Of the six populations with greater than 1,000 natural spawners, only two have a low
fraction of hatchery fish. Estimates of the historical equilibrium abundance, based on
pre-European settlement habitat conditions, range from 1,700 to 51,000 potential Puget
Sound Chinook salmon spawners per population. The historical estimates of spawner
capacity are several orders of magnitude higher than spawner abundances currently
observed throughout the ESU (Good, Waples et al. 2005).
Long-term trends in abundance and median population growth rates for naturally
spawning populations of Puget Sound Chinook salmon indicate that approximately half
of the populations are declining and the other half are increasing in abundance over the
length of available time series. Eight of 22 populations are declining over the short-term,
compared to 11 or 12 populations that have long-term declines (Good, Waples et al.
2005). Widespread declines and extirpations of spring- and summer-run Puget Sound
Chinook salmon populations represent a significant reduction in the life history diversity
of this ESU (Meyers, Kope et al. 1998). The median overall populations of long-term
trend in abundance is 1, indicating that most populations are just replacing themselves.
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