2007-2011 Total Chinook Encounters and Mortalities for Baseline-Sampled MSFs

Based on agreements between the State of Washington and the Northwest Treaty Tribes, the Washington Department of Fish and Wildlife (WDFW) has been conducting pilot¹ recreational mark-selective Chinook fisheries (MSFs) in the marine catch areas of Puget Sound since 2003. The goal of these fisheries is to allow increased angler opportunities on hatchery-raised, marked (adipose fin-clipped) salmon while limiting impacts on unmarked (adipose fin intact; typically wild origin) stocks of conservation concern, particularly ESA-listed Puget Sound Chinook.

To monitor each fishery, WDFW’s Puget Sound Sampling Unit (PSSU) implements one of the four following sampling designs: i) Full Murthy Estimate Design, ii) Reduced Murthy Estimate Design, iii) Aerial-Access Design or iv) Baseline Sampling Design. The design selected depends on area and season considerations, the magnitude of the fishery and State-Tribal agreements made prior to the start of the fishing season. For a complete description of the methods associated with these sampling designs, see WDFW’s �"Methods Report: Monitoring Mark-Selective Recreational Chinook Fisheries in the Marine Catch Areas of Puget Sound (Areas 5 through 13)” (WDFW 2012a).

The first three of the above-mentioned sampling designs (all except Baseline Sampling) are characterized as comprehensive, �"intensive” monitoring programs and have been tailored to reliably estimate the critical parameters needed for evaluating mark-selective fisheries (WDFW 2012a). In addition, PSSU has acquired and analyzed relevant data characterizing other aspects of the pilot MSFs, including descriptors of fishing effort, fishing success (catch [landed Chinook] per unit effort), recreational fishing methods, the length and age composition of encountered Chinook, and the overall intensity of our sampling efforts. As such, the data collected through these comprehensive monitoring programs allow biologists to produce weekly in-season estimates and timely finalized post-season estimates of effort, catch, total encounters and fishery impacts.

The fourth sampling design, Baseline Sampling, is a scaled-back monitoring program that is currently implemented in lower-magnitude MSFs (and year-round in non-selective sport fisheries) throughout Puget Sound. Table 1 presents a summary of the MSFs, by area and season in which PSSU has conducted Baseline Sampling, through the 2013-14 winter season. Samplers collect data on salmon catch (retained and released) and effort via dockside sampling and angler interviews and obtain on-water encounter rate data through distributing and collecting voluntary trip reports (VTR) from private anglers. In contrast to the three comprehensive monitoring programs, the data collected through Baseline Sampling does not allow for in-season or immediate post-season estimates of effort, landed catch, total encounters, or fishery impacts.

Between 2011 and 2013, an estimation framework was developed to estimate total Chinook encounters for a given MSF relying only on Baseline Sampling data and Catch Record Card (CRC) based Chinook harvest estimates (WDFW and NWIFC 2013). CRC harvest estimates are available approximately one year after the close of a fishery. Thus, while slightly delayed, this methodology allows for a full post-season analysis of Puget Sound Chinook MSFs that are sampled on a Baseline level only, including total size/mark-status specific estimates of encounters and mortalities.

As of the date of this report, finalized CRC-based estimates of Chinook harvest were available through the close of the 2011 summer season. Contained in the following sections is a full analysis of fishery-total encounters and mortalities associated with the 11 Puget Sound Chinook MSFs that were sampled on a Baseline level only through the 2011 Summer season. Included area estimates of: i) the total number of Chinook salmon harvested (by size [legal or sublegal] and mark-status [marked or unmarked] group), ii) the total number of Chinook salmon released (by size and mark-status group), iii) the total number of Chinook salmon mortalities (by size and mark-status group), iv) comparisons of Chinook salmon encounters and mortalities with pre-season expectations (based on Fishery Regulation Assessment Model [FRAM] predictions), v) sample rate information based on dockside sampling of harvested Chinook, and vi) the total mortality of marked and unmarked double index tag (DIT) CWT stocks. Estimates were derived using the estimation framework provided in WDFW and NWIFC (2013), referring to the decision support schematic to determine the estimator used.

¹ As stated in state-tribal agreement documents (e.g., WDFW and NWIFC 2009): â€�"The purpose of the ‘pilot’ fishery is to collect information necessary to enable evaluation and planning of potential future mark-selective fisheries. The ‘pilot’ fishery provides a basis for determining if the data needed to estimate critical parameters can be collected and if the sample sizes needed to produce these estimates with agreed levels of precision can be realistically obtained.”