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Saving our Native Yellowstone Cutthroat Trout
By Phil Barker
The Yellowstone Cutthroat trout of Henrys Lake are believed to have existed for over 9,000 years. IDFG’s last reproduction assessment revealed that less than 2% of all the YCT is naturally recurring; all others are manually spawned in the fish trap. This dramatic decline of naturally spawned YCT needs to be addressed before we lose our native fish forever.
Since 1982, the Henrys Lake Foundation has spent considerable time and monies working to protect the tributaries of Henrys Lake - the essential spawning and nursery habitat of our native YCT. The foundation along with our project partners have worked to:
· Improve fish passage in the tributaries by installing new bridges and road culverts
· Reduce sediment by fencing grazing areas and establishing hardened cattle water areas
· Plant willows to reinforce the stream banks, providing shade and structure as well as reduce sediment
· Protect the return of fingerlings into the lake by installing irrigation diversion screens to prevent them entering irrigation ditches as they migrate back into the lake.
Now, for the first time in HLF’s history, we are focusing on the native fish that enter the tributaries to spawn. The idea is to supplement their natural reproduction to ensure their survival by 1) identifying and capturing the native tributary spawners; 2) spawn them manually like we do for the fish that enter the fish trap; 3) rear them in the hatchery separately; 4) and then return them to the tributaries ‘off-cycle’ when they are larger in size. This process should increase the number of native spawners that re-enter the tributaries as well as increase the number of native YCT fingerlings returning to the lake. After several years, this should increase the native YCT percentage contribution to the total population of YCT in the lake.
To kick off the project, IDFG Regional Fisheries Manager Brett High suggests using fish genetics to build a "base case" for fish that spawn in the tributaries. The genetics will separate descendants of "native" fish that were not manually spawned in the fish trap from those that were. The native YCT that still exist can then be supplementally spawned using IDFG’s preferred method. Although this project is only in the IDFG planning and proposal stage, we anticipate that it can start next year.
Years ago, I remember speaking to a lady with a ranch on Rock Creek. She told me stories of 25” cutthroat in the creek when she was growing up. Rock Creek is a key tributary that feeds into Duck Creek - a critical spawning tributary on the west side of the lake. Some years ago, the HLF participated in replacing the bridges and culverts of both Red Rock and Duck creeks, all to improve fish passage. This new supplemental spawning project may make the migration of those monster YCTs into Rock Creek a reality once again, but many things need to go right for that to happen.
As we think about these types of preservation efforts, they are not easy problems to solve. The fingerlings of tributary spawned fish will compete for survival with the annual planting of about 1 million YCT, about 100,000 sterile brookies and about 200,000 sterile hybrids. The big brookies and hybrids have driven the popularity of the lake, but they are quite carnivorous. Along with other threats impacting fingerling survival, IDFG estimates that only 10% of planted fingerlings (all species) live to a catchable trout size. Even if we improve on that percentage for our native YCT fingerlings, this project will still take considerable time to show tangible results.
In 1982, the five fisherman who created our foundation set a reasonable goal for all of us to achieve: the preservation and protection of the fishery of Henrys Lake. This project is true to that goal but will require a significant commitment of time and resources - all of which cost money. We will fund this project though your generous donations along with any grants that we may be able to secure. Although this project is a bold undertaking, I am confident that IDFG will embrace this project with the full depth and breadth of their resources to make it a success; our native YCT depend on it.
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