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icon for How many Chinook will pass Bonneville Dam by October 31?
Climate & Science·Nature

How many Chinook will pass Bonneville Dam by October 31?

icon for How many Chinook will pass Bonneville Dam by October 31?
Climate & Science·Nature

How many Chinook will pass Bonneville Dam by October 31?

NEW
Oct 31, 2026
Polymarket

$2,648 Vol.

Polymarket

More than 550,000

$1,242 Vol.

90%

More than 575,000

$391 Vol.

84%

More than 600,000

$1,015 Vol.

66%

This market will resolve to "Yes" if "Chinook" Adult Passage Annual Count at Bonneville Dam from January 1, 2026 through October 31, 2026, 11:59 PM ET, exceeds the listed value. Otherwise, this market will resolve to "No". Each market in this event will resolve independently, and any number of these markets, including all or none, may resolve to "Yes". 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=10/31Recent passage data through mid-September 2026 show robust fall Chinook returns at Bonneville Dam, with 348,091 adult-sized fish counted since August 1, including record-high jack numbers that signal strong future cohorts. U.S. Army Corps of Engineers counts, corroborated by Washington and Oregon fisheries agencies, place the run ahead of recent averages, supporting Technical Advisory Committee projections of roughly 599,100 total adult fall Chinook reaching the Columbia River mouth. Key influences include river temperatures near Bonneville that affect migration speed and survival, plus ocean productivity shaping smolt-to-adult returns. Daily visual and video counts continue through November 30, with the next TAC update expected soon to refine in-season estimates ahead of the October 31 resolution window.

This market will resolve to "Yes" if "Chinook" Adult Passage Annual Count at Bonneville Dam from January 1, 2026 through October 31, 2026, 11:59 PM ET, exceeds the listed value. Otherwise, this market will resolve to "No". Each market in this event will resolve independently, and any number of these markets, including all or none, may resolve to "Yes".

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=10/31This market will resolve to "Yes" if "Chinook" Adult Passage Annual Count at Bonneville Dam from January 1, 2026 through October 31, 2026, 11:59 PM ET, exceeds the listed value. Otherwise, this market will resolve to "No". Each market in this event will resolve independently, and any number of these markets, including all or none, may resolve to "Yes". 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
Volume
$2,648
End Date
Nov 4, 2026
Market Opened
Sep 15, 2026, 5:12 PM ET

Resolution Source

https://www.cbr.washington.edu/dart/cs/php/rpt/adult_annual.php?outputFormat=html&proj=BON&startdate=1/1&enddate=10/31

Resolver

0x65070BE91...
This market will resolve to "Yes" if "Chinook" Adult Passage Annual Count at Bonneville Dam from January 1, 2026 through October 31, 2026, 11:59 PM ET, exceeds the listed value. Otherwise, this market will resolve to "No". Each market in this event will resolve independently, and any number of these markets, including all or none, may resolve to "Yes". 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=10/31Recent passage data through mid-September 2026 show robust fall Chinook returns at Bonneville Dam, with 348,091 adult-sized fish counted since August 1, including record-high jack numbers that signal strong future cohorts. U.S. Army Corps of Engineers counts, corroborated by Washington and Oregon fisheries agencies, place the run ahead of recent averages, supporting Technical Advisory Committee projections of roughly 599,100 total adult fall Chinook reaching the Columbia River mouth. Key influences include river temperatures near Bonneville that affect migration speed and survival, plus ocean productivity shaping smolt-to-adult returns. Daily visual and video counts continue through November 30, with the next TAC update expected soon to refine in-season estimates ahead of the October 31 resolution window.

This market will resolve to "Yes" if "Chinook" Adult Passage Annual Count at Bonneville Dam from January 1, 2026 through October 31, 2026, 11:59 PM ET, exceeds the listed value. Otherwise, this market will resolve to "No". Each market in this event will resolve independently, and any number of these markets, including all or none, may resolve to "Yes".

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=10/31This market will resolve to "Yes" if "Chinook" Adult Passage Annual Count at Bonneville Dam from January 1, 2026 through October 31, 2026, 11:59 PM ET, exceeds the listed value. Otherwise, this market will resolve to "No". Each market in this event will resolve independently, and any number of these markets, including all or none, may resolve to "Yes". 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
Volume
$2,648
End Date
Nov 4, 2026
Market Opened
Sep 15, 2026, 5:12 PM ET

Resolution Source

https://www.cbr.washington.edu/dart/cs/php/rpt/adult_annual.php?outputFormat=html&proj=BON&startdate=1/1&enddate=10/31

Resolver

0x65070BE91...

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Frequently Asked Questions

"How many Chinook will pass Bonneville Dam by October 31?" is a prediction market on Polymarket with 3 possible outcomes where traders buy and sell shares based on what they believe will happen. The current leading outcome is "More than 550,000" at 90%, followed by "More than 575,000" at 84%. Prices reflect real-time crowd-sourced probabilities. For example, a share priced at 90¢ implies that the market collectively assigns a 90% chance to that outcome. These odds shift continuously as traders react to new developments and information. Shares in the correct outcome are redeemable for $1 each upon market resolution.

"How many Chinook will pass Bonneville Dam by October 31?" is a newly created market on Polymarket, launched on Sep 15, 2026. As an early market, this is your opportunity to be among the first traders to set the odds and establish the market's initial price signals. You can also bookmark this page to track volume and trading activity as the market gains traction over time.

To trade on "How many Chinook will pass Bonneville Dam by October 31?," browse the 3 available outcomes listed on this page. Each outcome displays a current price representing the market's implied probability. To take a position, select the outcome you believe is most likely, choose "Yes" to trade in favor of it or "No" to trade against it, enter your amount, and click "Trade." If your chosen outcome is correct when the market resolves, your "Yes" shares pay out $1 each. If it's incorrect, they pay out $0. You can also sell your shares at any time before resolution if you want to lock in a profit or cut a loss.

The current frontrunner for "How many Chinook will pass Bonneville Dam by October 31?" is "More than 550,000" at 90%, meaning the market assigns a 90% chance to that outcome. The next closest outcome is "More than 575,000" at 84%. These odds update in real-time as traders buy and sell shares, so they reflect the latest collective view of what's most likely to happen. Check back frequently or bookmark this page to follow how the odds shift as new information emerges.

The resolution rules for "How many Chinook will pass Bonneville Dam by October 31?" define exactly what needs to happen for each outcome to be declared a winner — including the official data sources used to determine the result. You can review the complete resolution criteria in the "Rules" section on this page above the comments. We recommend reading the rules carefully before trading, as they specify the precise conditions, edge cases, and sources that govern how this market is settled.