EPA's Vessel General Permit and Small Vessel General

summer-run fish, comprising 37 of the 53 populations within this DPS.
Status and Trends
NMFS listed Puget Sound steelhead as a threatened species on May 11, 2007 (72 FR 26722). At
the time of the listing, the biological review team concluded that: the viability of Puget Sound
steelhead is at a high risk due to declining productivity and abundance; Puget Sound steelhead
are at moderate risk due to reduced spatial complexity and connectivity among populations
within the DPS, and reduction in life-history diversity within populations and from the threats
posed by artificial propagation and harvest. The Puget Sound steelhead DPS includes 53
putative populations; most of which are composed of winter-run fish. Summer-run populations
within Puget Sound are small, with most averaging less than 200 spawners, and most lack
sufficient data to estimate population abundance (Hard et al. 2007).
In general, steelhead are most abundant in the northern Puget Sound streams (Hard et al. 2007).
The largest populations in this DPS are in the Skagit River and Snohomish River winter-run
steelhead populations. The recent geometric mean escapement is 5,608 winter-run steelhead in
the Skagit, and 3,230 winter-run steelhead in the Snohomish River (Hard et al. 2007). The Green
River and Puyallup River populations, in central Puget Sound, are the next largest populations
and average approximately 1,500 (Green) and 1,000 (Puyallup) winter-run steelhead spawners
annually (Hard et al. 2007).
Estimates of historical abundance for this DPS are largely based on catch data. The earliest
catch records from commercial fisheries in the late 1880s indicate that the catch peaked at
163,796 steelhead in Puget Sound in 1895 (Hard et al. 2007). Based on this catch data, estimates
for the peak run size for Puget Sound steelhead ranges between 300,000 and 550,000 fish (Hard
et al. 2007). Given that most fish were harvested in terminal fisheries (nets set at the mouth of
rivers) NMFS expects that this estimate is a fair estimate of the Puget Sound DPS as it is unlikely
to include fish from neighboring rivers outside of the Puget Sound DPS. As early as 1898,
Washington officials expressed concerns that the run had declined by half of its size in only three
years (Hard et al. 2007). Since 1925, Washington has managed steelhead as a game fish, and in
1932 the State prohibited the commercial catch, possession or sale of steelhead.
Run size for this DPS was calculated in the early 1980s at about 100,000 winter-run fish and
20,000 summer-run fish. It is not clear what portion were hatchery fish, but a combined estimate
with coastal steelhead suggested that roughly 70% of steelhead in ocean runs were of hatchery
origin. Escapement of wild fish to spawning grounds would be much lower without the influx of
hatchery fish (Busby et al. 1996).
NMFS first status review for Puget Sound steelhead demonstrated that 80 % of the runs for
which there was data had declining trends in abundance. Busby et al., (1996) noted that the
largest decline, an 18% annual decline, occurred in the Lake Washington population. On the
contrary, the largest increase in abundance occurred in the Skykomish River winter-run steelhead
(the Skykomish River is a tributary to the Snohomish River) at a 7% annual increase. Estimates
of spawner abundance in the Skagit and Snohomish rivers, the two largest steelhead producing
basins in the DPS, were about 8,000 naturally spawning adult steelhead each. These two basins
exhibited modest overall upward trends at the time of the first status review. Recent data
demonstrates significant declines in the natural escapement of steelhead throughout the DPS,
116