Recent adult Chinook passage at Bonneville Dam remains strong, with daily counts exceeding 3,800 fish in mid-September 2026 per U.S. Army Corps of Engineers and DART data, consistent with fall-run timing where 50% passage historically occurs near September 17. Key drivers include Columbia River discharge and water temperatures monitored by USGS and NOAA, as elevated flows accelerate upstream migration while temperatures above 20°C can delay movement or increase stress for upriver bright and tule stocks. Ocean productivity and pre-season forecasts from state agencies shape overall run size, with in-season visual ecotype breakdowns from WDFW refining harvest and passage projections. Daily ladder counts and river environment updates through October will determine final totals before the October 31 cutoff.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedHow many Chinook will pass Bonneville Dam by October 31?
More than 550,000
91%
More than 575,000
57%
More than 600,000
25%
More than 625,000
10%
More than 650,000
6%
$5,167 Vol.
More than 550,000
91%
More than 575,000
57%
More than 600,000
25%
More than 625,000
10%
More than 650,000
6%
The qualifying data is the Adult Passage Annual Count for Bonneville Dam for the date range January 1, 2026 through October 31, 2026, 11:59 PM ET. Jack Chinook will not be considered for resolution. A value exactly equal to the listed value will resolve to "No". The value read for that date range is final, and counts for dates after October 31, 2026 are disregarded. The count is used as published, without expansion, interpolation, or adjustment, and annual and year-to-date summary totals are not used.
The resolution date is November 3, 2026, 11:59 PM ET, extending to November 17, 2026, 11:59 PM ET if the count through October 31, 2026 has not been published by that time. If DART has not published the count through October 31, 2026 by November 17, 2026, 11:59 PM ET, this market will resolve based on the available data. If Columbia River DART becomes unavailable and does not re-appear by November 17, 2026, 11:59 PM ET, all markets will resolve to "No". No substitute data provider will be used. Revisions published before the controlling deadline are incorporated; revisions published after the controlling deadline are disregarded.
The primary resolution source for this market will be the Columbia River DART Adult Passage Annual Count for Chinook at Bonneville Dam, available here: https://www.cbr.washington.edu/dart/cs/php/rpt/adult_annual.php?outputFormat=html&proj=BON&startdate=1/1&enddate=10/31
Market Opened: Sep 15, 2026, 5:12 PM ET
The qualifying data is the Adult Passage Annual Count for Bonneville Dam for the date range January 1, 2026 through October 31, 2026, 11:59 PM ET. Jack Chinook will not be considered for resolution. A value exactly equal to the listed value will resolve to "No". The value read for that date range is final, and counts for dates after October 31, 2026 are disregarded. The count is used as published, without expansion, interpolation, or adjustment, and annual and year-to-date summary totals are not used.
The resolution date is November 3, 2026, 11:59 PM ET, extending to November 17, 2026, 11:59 PM ET if the count through October 31, 2026 has not been published by that time. If DART has not published the count through October 31, 2026 by November 17, 2026, 11:59 PM ET, this market will resolve based on the available data. If Columbia River DART becomes unavailable and does not re-appear by November 17, 2026, 11:59 PM ET, all markets will resolve to "No". No substitute data provider will be used. Revisions published before the controlling deadline are incorporated; revisions published after the controlling deadline are disregarded.
The primary resolution source for this market will be the Columbia River DART Adult Passage Annual Count for Chinook at Bonneville Dam, available here: https://www.cbr.washington.edu/dart/cs/php/rpt/adult_annual.php?outputFormat=html&proj=BON&startdate=1/1&enddate=10/31
Recent adult Chinook passage at Bonneville Dam remains strong, with daily counts exceeding 3,800 fish in mid-September 2026 per U.S. Army Corps of Engineers and DART data, consistent with fall-run timing where 50% passage historically occurs near September 17. Key drivers include Columbia River discharge and water temperatures monitored by USGS and NOAA, as elevated flows accelerate upstream migration while temperatures above 20°C can delay movement or increase stress for upriver bright and tule stocks. Ocean productivity and pre-season forecasts from state agencies shape overall run size, with in-season visual ecotype breakdowns from WDFW refining harvest and passage projections. Daily ladder counts and river environment updates through October will determine final totals before the October 31 cutoff.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated


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