Steelhead PIT Tag Pilot Project

This Project was 100% funded by the Bureau of Indian Affairs Endangered Species Act Program.

The project includes funds to purchase one PIT tag detection antenna and 1,000 PIT tags. The tags will be implanted into yearling steelhead at the hatchery prior to their release at the Forks of the Smith River (the former release location). The antenna array that detects the PIT tags will be located at the confluence of the East Fork and West Branch of Mill Creek. The antenna array location, which is the same site that CDFW and the Smith River Alliance (SRA) used to monitor tagged Coho salmon in Mill Creek, is ideal as it provides a detection point downstream of the majority of the spawning and rearing areas favored by Coho. The detection of hatchery tagged individuals at the confluence in Mill Creek will indicate that the hatchery fish are in an area where juvenile Coho reside year round, and thus that the two are likely interacting. The potential interactions include hatchery steelhead predating on young of the year (YOY) Coho, larger hatchery steelhead juveniles outcompeting naturally produced Coho for preferable habitat, or the hatchery steelhead consuming prey species that Coho would have consumed in the absence of hatchery competitors. The potential interaction between hatchery steelhead and naturally produced Coho is not specific to juveniles, and data collected at the antenna site may document returning hatchery adults straying into Mill Creek where they may compete with Coho for available spawning habitat. Additionally, a hatchery origin adult steelhead may construct a redd on top of an existing Coho redd (superimposition), thus destroying the Coho redd, as Coho tend to spawn earlier in the winter. While PIT tag data will not allow direct observation of impacts of hatchery steelhead on Coho, the presence of hatchery steelhead in Mill Creek will provide evidence that the two species are present, and thus likely to have some level of interaction. 

 TDN will utilize PIT tagging equipment requested in this proposal as part of an overall strategy to increase monitoring of salmonids, both hatchery produced and naturally spawned, throughout the Smith River watershed. The proposed PIT tag monitoring will be paired with DIDSON monitoring to estimate total adult escapement for Chinook and steelhead, spawning surveys to document the proportion of hatchery origin adults straying into natural spawning areas, and juvenile dive surveys that will provide information on the spatial distribution of hatchery and natural origin juveniles.

 The goal of the “Investigating RCFH Juvenile Steelhead Impacts on SONCC Coho” project is to:

  • Release a tagged cohort of RCFH produced yearling steelhead at the Forks in Hiouchi and determine whether any tagged fish migrate up Mill Creek 
  • If hatchery fish are detected, use the data gathered at the PIT antenna to quantify the numbers of hatchery fish using Mill Creek, and how long they reside there

TDN will utilize PIT tagging equipment requested in this proposal as part of an overall strategy to increase knowledge of how the tribally-owned RCFH fish are impacting ESA-listed SONCC Coho salmon. The data obtained will inform the decision to pursue re-locating the hatchery release site to its former location, thus potentially restoring the intended impacts of RCFH to enhance harvestable fish populations for Tribal subsistence harvest while also stimulating the local economy. With the current release site located downstream of most fishing effort, the facility is currently not meeting those goals. TDN, as the original stewards of the Smith River, wish to operate the hatchery in a way that maximizes subsistence harvest opportunity while minimizing risks to naturally produced fish in the watershed.