Potlatch River Steelhead Monitoring & Evaluation

The following is a worksite summary of work completed through this Project.

Worksite 1, East Fork Potlatch River Adult Weir/Screw Trap:

Steelhead were monitored at the adult weir covering 56.5 miles of the East Fork Potlatch River (EFK) from March 1–June 3, 2013 during the spawning migration. There were 82 pre-spawn steelhead captured at the weir and all recaptured kelts were previously marked as upstream spawners resulting in an adult escapement of 82 fish. The EFK weir was operated from March 22–June 3, 2014: 78 steelhead were marked and released as upstream spawners and 34 were captured as downstream kelts, 27 fish being recaptures. Total 2014 mark-recapture escapement estimate for the EFK was 96 fish (95% CI 78 -115).

Steelhead smolt monitoring was also conducted at this worksite through the use of a screw trap. Mark-recapture juvenile steelhead trapping for the EFK during the 2013 field season resulted in outmigration estimates of 48,052 (95%CI, 37,528 - 62,232). The 2014 mark-recapture of juvenile steelhead resulted in outmigration estimates of 16,753 fish (95% CI 10,143 - 30,807).

Scales were collected at the weir and screw trap to determine the age of fish to assign brood year production to the juvenile outmigrants.

Worksite 2, Big Bear Creek Screw Trap:

Steelhead smolt monitoring was conducted at this worksite using a screw trap, monitoring 63 miles of the Big Bear Creek drainage. Mark-recapture juvenile steelhead trapping at the trap during in 2013 resulted in outmigration estimates of 19,808 (95%CI, 17,921 - 22,119) and during the 2014 field season outmigration estimates were 8,355 fish (95% CI 7,650 - 9,101).

Scales were collected at the weir and screw trap to determine the age of fish to assign brood year production to the juvenile outmigrants.

Worksite 3, Potlatch River Basin-wide Monitoring:

208 miles of the Potlatch River drainage were monitored through electrofishing surveys during the roving tagging during the contract term; in 2013 1,505 juvenile steelhead were captured and tagged and in 2014 1,306 were captured and tagged. Arrival rates of the 2013 tag groups to Lower Granite Dam in 2014 were highest from Big Bear Creek and West Fork Little Bear Creek at 13% and 10% respectively. Pine Creek, Little Bear Creek, and East Fork Potlatch River had the lowest arrival rates at 5-6%. Detections of the 2014 tag groups at instream arrays in the Potlatch River and at Lower Granite Dam in spring 2015 will enable estimates to be made of in-stream survival for the different tributaries.

7 miles of habitat were surveyed using the low water habitat availability protocol during the contract term. Surveys were conducted in lower Potlatch drainages from August 1–8, 2013 and July 29-August 8, 2014. Between 95-99% of stream channel lengths in the treatment tributaries were wetted during the first week of August 2013 and in 2014 between 84-95% of stream channel lengths in the treatment tributaries were wetted. 50% of stream channel lengths in Pine Creek, the control tributary were wetted during the first week of August. Pool density was highest in Little Bear Creek and lowest in Pine Creek in both 2013 and 2014.

The monitoring and evaluation effort within the Potlatch River drainage is focused on Snake River Basin ESU Steelhead. Work funded by previous PCSRF and NOAA IMW funds has successfully established a baseline recruit/spawner productivity curve for the Big Bear Creek Drainage. The recruits/spawner productivity relationship is key to understanding the benefit of habitat restoration and its impact on freshwater productivity. This proposal will continue similar work within the East Fork Potlatch River where the baseline recruits/spawner productivity curve has yet to be completed. The proposal will also fund roving PIT tagging efforts in both the Big Bear Creek and East Fork Potlatch River drainages. This work will provide insight into summer rearing survival, life history characteristics and juvenile steelhead growth within the two index tributary areas. This data will also be used to track habitat restoration success as it relates to density dependent factors within these drainages.