Emergency closures illustrate Mat-Su coho salmon devastation

Effective August 15, 2024 the Alaska Department of Fish and Game (ADF&G) announced sport coho salmon fishing would be closed through September 30, 2024 in the entire Susitna River drainage (including Deshka River), in the Little Susitna River, Fish Creek, Cottonwood Creek, Wasilla Creek, and the entire Knik River drainage (including Jim Creek). Note: ADF&G has only 4 coho salmon spawning escapement goals for Upper Cook Inlet, an area stretching from Anchor Point near Homer nearly to Cantwell up the Parks Highway and to the headwaters of the Matanuska River drainage up the Glenn Highway. Upper Cook Inlet Coho salmon goal locations are Little Susitna River, McRoberts Creek ( a portion of Jim Creek drainage), Deshka River, and Fish Creek. Because of documented low numbers of returning wild coho salmon, sport coho salmon fishing has now been emergency closed (effectively for the remainder of the season) at EVERY Upper Cook Inlet freshwater drainage with an ADF&G established coho salmon spawning escapement goal.

Level of Coho Salmon Shortage According to the ADF&G announcement for the Susitna River drainage, “The Deshka River coho salmon sustainable escapement goal (SEG) is 10,200–24,100 fish. As of August 12, only 642 coho salmon have passed upstream of the weir with a projected escapement of 1,375 fish.” Note: That the Deshka River coho salmon escapement projection has not improved, even with earlier established restrictions, as back on August 2 in a previous ADF&G announcement reducing the sport coho salmon daily bag limit to one fish and prohibited bait throughout the entire Susitna River drainage, ADF&G’s projected coho salmon escapement at Deshka River was listed as 1,444 fish.

According to the August 12 ADF&G announcement closing coho salmon fishing in the Little Susitna River and other Knik Arm locations, “As of August 12, only 878 coho salmon had passed upstream of the Little Susitna River weir and the escapement is projected to be 2,154 fish.” Note: The projected Little Susitna River coho salmon spawning escapement has actually declined by over 50% since a sport fishing bait prohibition and bag limit reduction was announce on August 2, at which date ADF&G’s coho salmon escapement projection for Little Susitna River was 5,291`fish.

Importance of Little Susitna River and Deshka River Coho Goals ADF&G’s Little Susitna River coho salmon spawning escapement goal was the first coho salmon goal established in Upper Cook Inlet, and has a high correlation with coho salmon escapements throughout Knik Arm drainages — so it can be used to conservatively manage Knik Arm coho salmon stocks as a unit. In addition, Little Susitna River was for more than a decade, one of the most productive freshwater coho salmon sport fisheries in the entire State of Alaska. The Department considered the Little Susitna River freshwater sport coho salmon fishery to be the 2nd largest freshwater sport coho salmon fishery in the entire state — second only to the Kenai River. Sport coho salmon harvests from Little Susitna River has fallen by over 70% since that time. Both the actual weir count of 878 coho salmon or the weir based projected Little Susitna River coho salmon escapement of 2,154 fish would be lower than all the other actual counted escapements listed on ADF&G’s website for a period of 28 years. Historically the highpoint weir-based coho salmon spawning escapement count for Little Susitna River was 47,938 fish in 2002.

ADF&G considers the Deshka River coho salmon goal to be an indicator of coho salmon abundance for the entire Susitna River drainage (including the Yentna, Talkeetna, and Chulitna River drianage). Both the actual count of 642 coho salmon and the projected final escapement of 1,375 fish would be lower than any actual coho count at Deshka River in 28 years of records on ADF&G’s website. Historically the highpoint weir-based coho salmon escapement count for Deshka River was 62,940 fish in 2004. In discussions I’ve had with ADF&G biologists, Deshka River coho production has been estimated to be as high as 20% of coho production for the entire Susitna River drainage (I believe data may show Deshka coho to be a somewhat lower percentage). Using the 20%,figure, however, would indicate Susitna drainage coho escapement of approximately 314,700 fish in 2004 compared to a Susitna drainage coho escapement projection of approximately 6,925 fish for 2024.

Deshka River and Little Susitna River Weirs Flooded — Following a period of prolonged rain both Deshka River and Little Susitna River weirs have been overtopped with flood water. No salmon were counted at Deshka River on Saturday, Sunday, and Monday August 10, 11, and 12, with river flows high enough to damage the weir structure. ADF&G will be working at getting the weir above water and operating, but it is unknown at this time when that may be. Little Susitna River was overtopped with water starting Friday August 9, resulting in no salmon passage counts on August 9, 10, 11, and 12. The water level has been dropping, and with less weir damage, Little Susitna River weir will likely be up and operating again before Deshka River weir. Coho salmon escapement projections made before these weirs went underwater may provide some of the most reliable management data for both of these locations -- depending upon how soon one or both weirs may be operable again.

Value of Fish Creek and Jim Creek Weirs Both Fish Creek and Jim Creek weir counts remain fully operable throughout the season, to date, with counts of both sockeye salmon and coho salmon passage. Weirs at these more stable stream flow locations are more likely to provide a full season of uninterrupted salmon escapements that is beneficial on a broader management perspective if / when floodwaters interrupt coho counts at Deshka River or Little Susitna River weirs. Fish Creek weir is the one location where a Mat-Su Valley salmon escapement goal has been met in 2024. Although additional daily Fish Creek weir counts were unposted at the time this column was written, the midpoint of the Fish Creek Sockeye Salmon Escapement Goal of 15,000 - 45,000 fish was exceeded on July 31.

Shortages of coho salmon at Jim Creek and Fish Creek weirs confirmed the low trends observed at Deshka and Little Susitna River weirs, and were used in creating restrictions, and then closures, to better ensure adequate coho salmon spawning escapement levels to maintain future Northern Cook Inlet coho salmon production.

Escapement data from Larson Lake weir in the Talkeetna River drainage has not been updated since August 8, however it appears the minimum threshold of the Larson Lake sockeye salmon goal could be attained before long. The goal is 15,000 - 45,0000 fish and through August 8 the escapement count was 11,794 fish.

Mat-Su Salmon Fishing Opportunities Sockeye salmon counts have started tailing off at Mat-Su locations, even so, sockeye fisheries at the Larson Creek/ Talkeetna River confluence, Lake Creek in the Yentna River drainage, and Jim Creek, Cottonwood, and Fish Creek in the Knik Arm drainage may continue to provide some of the best Mat-Su sport harvest opportunities now that most Mat-Su coho salmon fisheries have been closed. The hatchery-enhanced Eklutna Tailrace coho salmon fishery, encompassing the tailrace channel and then all Knik River waters within 1/2 mile of the tailrace / Knik River confluence downstream for 2 miles to the ADF&G regulatory marker remain open to the use of bait with a daily limit of 3 salmon per person (all of which may be coho). Note: the Eklutna Tailrace Youth fishery is scheduled to occur Saturday August 17 from 6 am - 6pm from the pedestrian bridge to the tailrace / Knik River confluence. Fishing in this area will be restricted to youth less than 16 years of age, while fishing in other tailrace and Knik River waters remains open to anglers of all ages.

Chum and pink salmon fishing opportunities remain open throughout the Susitna River drainage and in Little Susitna River downstream of the Parks Highway bridge (although anglers keeping salmon for table fare may want to be very selective, when harvesting either pink salmon or chum salmon this late in August.

While most Mat-Su salmon populations may appear to be in rapid decline, next week I intend to suggest some solutions that would better ensure higher Mat-Su salmon spawning escapement numbers, and more reasonable fishing opportunities for all user groups.

Good Luck and Fish On!