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

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Status <strong>and</strong> Trends<br />

SR fall-run Chinook salmon were originally listed as threatened in 1992 (57 FR 14653).<br />

Their classification was reaffirmed following a status review on June 28, 2005 (70 FR<br />

37160). Estimated annual returns for the period 1938 to 1949 was 72,000 fish. By the<br />

1950s, numbers had declined to an annual average of 29,000 fish (Bjornn <strong>and</strong> Horner<br />

1980). Numbers of SR fall-run Chinook salmon continued to decline during the 1960s<br />

<strong>and</strong> 1970s as approximately 80% of their historic habitat was eliminated or severely<br />

degraded by the construction of the Hells Canyon complex (1958 to 1967) <strong>and</strong> the lower<br />

SR dams (1961 to 1975). Counts of natural-origin adult SR fall-run Chinook salmon at<br />

Lower Granite Dam were 1,000 fish in 1975, <strong>and</strong> ranged from 78 to 905 fish (with an<br />

average of 489 fish) over the ensuing 25-year period (Good, Waples et al. 2005).<br />

Numbers of natural-origin SR fall-run Chinook salmon have increased over the last few<br />

years, with estimates at Lower Granite Dam of 2,652 fish in 2001, 2,095 fish in 2002, <strong>and</strong><br />

3,895 fish in 2003.<br />

SR fall-run Chinook salmon have exhibited an upward trend in returns over Lower<br />

Granite Dam since the mid-1990s. Returns classified as natural-origin exceeded 2,600<br />

fish in 2001, compared to a 1997-2001 geometric mean natural-origin count of 871.<br />

Long- <strong>and</strong> short-term trends in natural returns are positive. Harvest impacts on SR fallrun<br />

Chinook salmon declined after listing <strong>and</strong> have remained relatively constant in recent<br />

years. There have been major reductions in fisheries impacting this stock. Mainstem<br />

conditions for subyearling Chinook salmon migrants from the SR have generally<br />

improved since the early 1990s. The hatchery component, derived from outside the<br />

basin, has decreased as a percentage of the run at Lower Granite Dam from the 1998/99<br />

status reviews (five year average of 26.2%) to 2001 (8%). This reflects an increase in the<br />

Lyons Ferry component, systematic removal of marked hatchery fish at the Lower<br />

Granite trap, <strong>and</strong> modifications to the Umatilla supplementation program to increase<br />

homing of fall Chinook release groups.<br />

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