In 1958 the Washing Department of Fisheries built a trap and haul facility below Sunset Falls on the South Fork of the Skykomish River to allow anadromous fish passage over a complex of three falls. Sunset falls is the first of the three falls, located 2 miles upstream from the confluence of the North and South forks of the Skykomish, with a 90 foot vertical drop. Next is Canyon Falls with a 50 foot drop, and 4 miles upstream from Sunset is Eagle Falls with a 25 foot drop. Fish are trapped below Sunset and hauled above Eagle Falls for release. The drainage area above Sunset Falls is approximately 350 square miles and encompasses major tributaries that include the Miller, Beckler, Foss, and Tye Rivers and numerous creeks including, Money, Deception and Tunnel.
The trap typically opens in early to mid July and operation continues until mid to late December. During the early 60's ('61-’65), operations continued into January and February with the latest closing being February 18. This may have been an attempt to pass winter steelhead upstream and/or to accommodate the winter run planting made in 1961 discussed below.
Since opening, the facility has passed an average of 25,000 total fish per year. With the recent increases of pink salmon returns in the last ten years, the average has risen to 46,000 (26,000 even, 66,000 odd).
Some people view the Sunset Falls project as partial mitigation for the impacts that development and land use changes have had in the lower river.
Steelhead
Coho
Chinook
Pink
Chum
Sockeye
Bull Trout
Prior to 1958, winter-run steelhead were planted in the SFSKY. Winter-run smolts were planted between 1935 and 1952.
In 1961, a plant of 3,300 winter run smolts was made. After that, summer run plants were initiated in 1964 with approximately 31,000 Skamania stock smolts. Summer-run plantings were ongoing, but not yearly, from 1968 thru 1992, principally from the Reiter Ponds stock (original stock composed of both Skamania and North Fork Skykomish native summer run) and generally in the form of smolts, although 3 fry plantings were made. There have been no hatchery plantings into the SFSKY since 1992, although marked hatchery origin fish entering the trap at Sunset Falls were passed upstream until 2008.
Reiter Ponds, located approximately 6 miles downstream from Sunset Falls on the main stem Skykomish River, began its operation with releases in 1975. The Reiter Ponds summer run releases have contributed to the marked fish returning to Sunset Falls, and are assumed to be the primary source of marked fish since about 1995, when the adults from the last planting in the SFSKY would have finished returning. Beginning with 1993, breakouts of marked (H) and unmarked (W) steelhead returning to sunset falls are available.
Total steelhead returns to Sunset Falls were between 300 and 500 fish in the early 70's. There were no hatchery plants in SFSKY from '69-74, (although there were other summer-run plants in the Skykomish basin.). So, the returns of '73-76, 400 fish per year, might be an indicator of unsupplemented, self-sustaining productivity (less any harvest interception that may have occured).
Total steelhead returns grew to 1200 to 1500 in the mid 80's, and peaked at over 2000 in 2000 and 2001. Since 2001 total returns to the trap have declined steeply, but have stabilized over the last 5 years between 350 and 500.
Since 1993, the period for which break outs between marked (H) and unmarked (W) fish are available, unmarked (W) fish have comprised 25 -90% of the fish entering the trap at Sunset Falls. From '93 to '02 the unmarked fish entering the trap averaged 749 with a range of 453 – 1096. From '03 -'11 the unmarked fish entering the trap have averaged 311 with a range of 116 - 498.
Beginning in 2008, marked (H) steelhead have not been passed upstream to the extent practical that is consistent with safely moving all of the fish entering the trap. What that means is that when the trap is swamped with pinks or coho, some of the marked steelhead may be identified but not removed. Fish removed are sent to a hatchery facility. The results from limiting marked fish being passed upstream are as follows:
Marked (Hatchery) Steelhead
Year Entering Trap Shipped (elsewhere) Released upstream Reduction
of Eagle Falls (SFSKY)
2009 195 136 59 70%
2010 114 114 0 100%
2011 123 102 21 83%
Genetic testing was undertaken of the wild summer run steelhead passed upriver of Sunset Falls based on samples taken in 2002. Although the sample size was small, there is a basis to say that the ancestry of the unmarked fish passed above sunset falls in 2002 was approximately 80% more similar to the Reiter Ponds stock and 20% more similar to the North Fork Skykomish native stock.
The run of coho in the SFSKY is also thought to be of naturalized hatchery stock. Plantings of coho were initiated in the 50's, prior to the fish passage construction ('52-58). Some 2.25 million fry and fingerlings were planted of both Skykomish and Green river coho stocks. Fry accounted for 90% of the plantings. Skykomish stock predominated 2 to 1 over Green River stock, although Green River stock predominated the later plantings. No plantings have been made since 1958.
This run has made a major contribution to the Snohomish River system as a whole, typically accounting for 20% of coho production in the entire basin.
A peak return of 50,000 was reached in 2001.
The SFSKY is believed to be fully seeded with 6-7,000 females spawning.
Female coho escapement was artificially lowered (fish removed) in '81-83, in order to explore the low end range of the spawner/recruit curve and contributed to the dip in returns seen in '84-85.
Escapement above Sunset Falls has averaged 17,500 coho per year over the life of the project. The recent 10 year average (2002-2011) is 24,000.
Hatchery coho are not thought to stray to Sunset Falls in significant numbers.
Jacks are a consistent but small portion of the run, typically 1.5% (200), although they have reached as high as 11%.
Beginning with 2005, approximately 2% of the coho returning to Sunset Falls have been taken as hatchery broodstock (385 fish on average). These are not depicted in the graph because they are too small to see.
The current odd-even yoyo effect in the escapement may well be an interaction with the pink stocks and the effects of carcass based nutrient additions.
This stock has become a key stock for basing abundance forecasts for the entire basin due to the counting enabled by the fish passage facility.
The run of chinook in the SFSKY is of natural origin.
Chinook seem to have colonized this habitat faster, in some sort of relative sense, than some of the other stocks that were not planted. Escapements above Sunset Falls grew steadily after its opening, and reached a peak in 1974 of 1570 fish. From the mid 70's through the mid 80's escapements declined steadily and then began growing again, reaching a second peak of 1100 fish in 2001 (the same year that coho topped 50,000). Since then they are once again on the decline.
Chinook returning to Sunset Falls have typically accounted for 10-20% of the summer/fall chinook escapement in the Snohomish system.
Beginning in 2005, approximately 18% of the Chinook returning to Sunset Falls have been taken as hatchery broodstock (about 90 fish on average). These are depicted on the graph as “ Adults Not Passed ”.
Jacks form a significant additional component of the SFSKY chinook run, typically accounting for 22% (range 3-45%) of the total chinook return.
The run of pink salmon in the SFSKY is of natural origin.
Pink salmon (odd-year) made limited, but steadily increasing, use of SFSKY after the opening of the Sunset Falls facility, reaching 1800 fish in 1971.
Escapements declined through the 70's and rebounded in the 80's, reaching approximately 22,000 in '85 and '89. Escapements declined during the 90's and have rebounded again since 2001, reaching a peak of 98,000 in 2009.
SFSKY pink escapement is not particularly well correlated to the escapement for rest of the Snohomish River System. From 1983 to 2003 its contribution to the total system escapement averaged 7.4% but ranged from 0.4% to 27% (SD=7.7%)
Even-year pink salmon have occasionally returned to Sunset Falls; 5 different years, 11 total fish.
The chum run" on the SFSKY is of natural origin. Of the salmon runs, chum have been the slowest to utilize the habitat of the SFSKY. It is not known if they are particularly successful at spawning in the habitat available.
From the opening of the Sunset Falls facility until 1985, chum passage was small and spotty,– 4 fish per year average, range 0-22. In 1986, 182 chum arrived and usage has been larger, but still relatively sporadic since. There was a surge of sorts in 2001-04, with a peak of 600 fish in 2004. A mini bump in 2007-08 may have been the result of returns earlier in the decade, but the recent returns have declined to 18 fish per year (2009-11.)
A small but persistent run of sockeye have made use of the Sunset Falls facility.
These are thought to be a river type as opposed to a lake type sockeye. They are not thought to be strays from major lake type runs in the region.
Since the opening of the passage facility, they have averaged 17 fish per year, with three years of no return and high counts of 69, 53 and 51. Consistency has improved over the last 20 years and there is a slight upward trend over the last 10 years.
The WDFW has a blurb on these type of sockeye
Counting of the bull trout passed at Sunset Falls began in 1994. From 1994 to 2004 the annual number of bull trout passed grew steadily from 18 to 128. Since then it has fluctuated between 50 and 100 with an average of 75.
©2003 -– 2011 Steelhead Trout Club of Washington
