a month with the number of sea lions hanging out at Bonneville Dam to snack on
salmon, steelhead and other available fish exceeding the 10-year average, the
number fell to just one, according to a June 7 report.
of the Steller sea lions left by May 27 and by the end of the reporting period,
May 13 to June 2, there were none remaining at the dam. The bulk of the
California sea lions left by May 30, but one remains, the report says. During
the period there were an average of 37.5 sea lions in the dam’s tailrace per
day. Most were Steller sea lions, averaging 24.3. California sea lions averaged
13.1 over the same period. No seals were present at the dam this year.
at the dam, the sea lions’ relative impact on the small run of spring chinook
and lagging numbers of steelhead was likely large.
U.S. Corps of Engineer’s June 7 report (Bi-Weekly Update: Pinniped Abundance
and Salmon Predation at Bonneville Lock and Dam), the fourth and final report
of the year, says about 1,837 adult salmonids were consumed by the sea lions
May 13 to June 2, far higher than the 10-year average for the same period of
437 adult salmonids.
report was prepared by Kyle Tidwell, Thomas Van Hevelingen, Lindsay Magill, and
Bjorn van der Leeuw, all of the Corps’ Fisheries Field Unit (http://www.nwd-c.usace.army.mil/tmt/documents/pinniped/2017/20170608-Bonneville%20Pinniped%20update.pdf).
the entire reporting period (January 1 – June 2), sea lions ate 4,993 adult
salmonids. Some 82 percent of those were spring chinook salmon. Six sturgeon
were eaten, according to observers, and lamprey and other non-salmonids
accounted for less than 5 percent of the predation.
review of the combined salmonid passage counts for the pinniped sampling season
shows that the runs were delayed relative to previous years and smaller than
the long term average,” the report says. “As such, the duration of pinniped
presence and levels of fish predation were protracted relative to the 10 year
average. The reduced salmonid runs and persistently high numbers of pinnipeds
in the latter part of the season suggests that the total impact by pinnipeds on
this year’s salmonid run may be large.”
final predation numbers are being processed and will be available at a later
clear this year is that the spring chinook run was far lower than average. The
U.S. v Oregon Technical Advisory Committee initially predicted a run of 160,400
fish. That was revised down by TAC to 118,000 fish arriving at the mouth of the
Columbia River and 110,000 fish over Bonneville Dam. The spring chinook run
over the dam transitioned to the summer chinook run June 15.
June 15, some 107,524 adult spring chinook had passed Bonneville.
documented 15 Steller and 88 California sea lions as uniquely identifiable
individuals. All uniquely identifiable pinnipeds have been documented near
Bonneville tailraces project in previous years or were recently branded at
sea lions have been observed at the Dalles Dam or above the Bonneville Dam
since May 18.
at the dam began January 10 and concluded June 2.
and trapping activities are fully operational with all state, tribal, and
federal entities working together to monitor this year’s pinniped-fish
24 of the California sea lions that have been identified, marked and trapped,
have been euthanized this year. Two were euthanized the week of May 15, eight
the week of May 8, six the week of May 1, seven the week of April 24 and one
the week of April 17. Trapping reports are at http://www.dfw.state.or.us/fish/SeaLion/.
April, two members of the Northwest’s congressional delegation – U.S. Reps.
Jaime Herrera Beutler (R-WA) and Kurt Schrader (D-OR) – introduced the
Endangered Salmon and Fisheries Predation Act in Congress to expedite the
removal of sea lions at Bonneville Dam that would make it easier for tribes and
states to obtain permits to remove sea lions from the Bonneville Dam tailrace.
That bill is still in committee.
June 9, 2017, “Spring Chinook Run Forecast Stays At 118,000 As Harvest Managers
Move Into Summer Chinook Season,” http://www.cbbulletin.com/439057.aspx
May 12, 2017, “Sea Lion Numbers At Bonneville Increase, Salmon Predation Below
Average So Far,” http://www.cbbulletin.com/438900.aspx
CBB, April 28, 2017, “Slow Start This Year But Sea Lions Back At Bonneville Dam
For Spring Chinook Feasting,” http://www.cbbulletin.com/438804.aspx
CBB, April 14, 2017, “Bill Introduced In Congress Again To Expedite Removal Of
Sea Lions From Bonneville Dam Tailrace,” http://www.cbbulletin.com/438711.aspx
CBB, March 10, 2017, “Corps Report: Sea Lions In Bonneville Dam Tailrace In
2016 Consumed 4.5 Percent Of Spring Chinook,” http://www.cbbulletin.com/438453.aspx
June 17, 2016, “Final 2016 Pinniped Report: Sea Lion Salmon Take Astoria To
Bonneville Dam Could Be 20 Percent Of Run,” http://www.cbbulletin.com/436941.aspx
CBB, June 19, 2015, “Final 2015 Sea Lion Predation Report: 8,474 Salmonids
Taken Below Bonneville, Twice 10-Year Average,” http://www.cbbulletin.com/434287.aspx