Assessment of the Geographic Distribution for Coho Salmon in tributaries of the Lower Klamath River - Yurok

Task 1 will focus on assesses juvenile Coho and other salmonid species spatial distribution and density throughout the Lower Klamath tributaries. The proposed project would survey the entire sampling universe (22 tributaries, 69 reaches) that was built for the Lower Klamath region and contains all the habitat historically occupied by Coho Salmon. Including the entire sampling frame addresses a major problem spawner survey methodology where randomly selected reaches primarily consisted of marginal habitat. Assessing adult populations required repeat surveys from December-February that reduced the number of reaches that could be surveyed in a given year (20 reaches). Determining spatial distribution for juvenile Coho Salmon only requires one survey in a given year and these are conducted in the low flow period during late summer and early fall. By only conducting a single survey it is possible to include the entire sampling universe in a given year. Juvenile Coho Salmon are more numerous than adults which greatly increases the probability of detecting the species in a given pool or reach. The reliability of a surveyor correctly identifying species is much greater for juvenile Coho Salmon than assigning species to redds.

The proposed methodology for assessing the spatial structure of Lower Klamath Coho Salmon is described in Garwood and Ricker (2014). Counts of juvenile Coho and other salmonid species will be conducted through snorkeling every other pool in each sampling reach. Every fourth pool will be snorkeled by another person to obtain observer efficiency estimates. Other information that will be collected during surveys includes pool surface area and large wood counts. Pool surface area and juvenile counts provide a density estimate that can be used to compare relative abundance among the survey reaches. Large wood counts can be used to identify areas for future restoration projects that include wood loading. Information on spatial structure, juvenile Coho Salmon density, and large wood counts are critical for making informed decisions on potential restoration projects in the Lower Klamath region. Current data on most lower Klamath tributaries is lacking since the last comprehensive survey of juvenile Coho Salmon in lower Klamath tributaries occurred over 20 years ago (Voight and Gale 1998).

Task 2 will focuses on long-term juvenile salmonid production emigrating from Blue Creek and McGarvey Creek. The goals of the project include quantifying abundance for annual trend analysis of outmigrating juvenile salmonid runs. These two streams have undergone extensive watershed restoration planning, implementation, and monitoring since the mid-1990’s. The Yurok Tribal Fisheries Program (YTFP) initiated annual outmigrant trapping projects in Blue and McGarvey Creeks in 1995 and 1997, respectively. Objectives of the project include: 1) quantitatively determine the production of juvenile Chinook and Coho through the sampling of downstream migrants in both drainages during 2023. 2) assess emigration timing and species and size composition for all fish species (including cutthroat trout and steelhead) sampled, and determine age composition for all juvenile steelhead and Cutthroat sampled; 2) in McGarvey Creek, juvenile Coho will be PIT tagged to assess growth, movement, and survival through the use of trapping and SPI data, 3) Blue Creek Chinook abundance data will be used to assess trends over time, carrying capacity, and maximum sustainable yield to assist with establishing Tribal harvest management objectives, 4) provide the Tribe with data for input into Lower Klamath resource management planning, including habitat restoration, treaty fishing rights, and ESA-related issues.

To assess spatial distribution and densities of juvenile Coho Salmonid in tributaries of the Lower Klamath River. Coho Salmon in the SONCC ESU are listed as threatened under both federal and state endangered species acts. To either delist a salmon species

or change the status from threatened to endangered requires information on the abundance of populations in ESU’s over time. The development of VSP framework to assess salmonid population viability within ESU’s. The VSP framework is based on four viability metrics that measure: abundance, productivity, spatial structure, and diversity. These metrics are the basis for assessing when a listed species has recovered. This project will provide information for a critical element of the VSP (spatial structure) within the Lower Klamath region is lacking and prevents National Marine Fisheries Service from making informed decisions on the status of this independent population. Information on spatial structure, juvenile Coho Salmon density are critical for making informed decisions on potential restoration projects in the Lower Klamath region.

This project will provide data so that management actions (timber harvest, road maintenance, restoration efforts, and harvest management of late-run fall Chinook) can be improved with respect to their effect on anadromous fish in general, and particularly with respect to ESA-listed SONCC Coho Salmon and late-fall Chinook Salmon of Blue Creek and McGarvey Creek.



In McGarvey Creek, considerable restoration has addressed limiting factors to juvenile Coho production through introduction of large woody debris, engineered log jams, reforestation, creation of off-channel habitat (alcoves), and installation of beaver dam analogs. Success of these projects will be assessed through the continuation of the long-term data set for estimates of juvenile Coho outmigrants at the McGarvey Creek Pipe Trap. Furthermore, we are currently conducting analysis of overwinter survival for PIT tagged McGarvey Creek juvenile Coho from brood year 2009 forward. An increase in overwinter survival over time will infer that creation of over-winter habitat through restoration has resulted in a positive population response. We have also started to measure over-summer survival beginning in the summer of 2015. Analysis of over-winter/over-summer survival estimate trends over time will be used to assess whether restoration actions have addressed limiting factors in the McGarvey Creek watershed.

Recent restoration actions in the Blue Creek watershed include tribal acquisition of large tracts of the Blue Creek watershed and upslope restoration activities. Over 15,000 acres have been designated as an old growth forest preserve. Furthermore, considerable instream restoration is planned for the Blue Creek watershed. Continuation of the long term monitoring of juvenile Chinook production at the Blue Creek rotary screw trap will help inform the success of these restoration actions. In addition, we use this information to analyze the stock recruitment for Blue Creek late-fall Chinook to help manage and protect the Tribe’s federally reserved fishing right.