Fishing / Shellfishing - Selective Fishing
Date Published: June 29, 2010
Number of Pages: 62
Author(s): Mark Baltzell, Steve Caromile, Karen Kloempken, and Laurie Peterson
Background and Overview
The Washington Department of Fish and Wildlife (WDFW) implemented mark-selective Chinook fisheries (MSFs) in Marine Areas 5 and 6 for the seventh time during the summer of 2009 (July 1-August 6). Consistent with the 2004 Puget Sound Chinook Harvest Management Plan (Puget Sound Indian Tribes and WDFW 2004) and the intent of previous Puget Sound/Strait of Juan de Fuca mark-selective Chinook fisheries, the primary goal for these fisheries was to provide meaningful opportunity to the recreational angling public while minimally impacting ESA-listed Puget Sound Chinook salmon.
WDFW’s Puget Sound Sampling Unit (PSSU) conducted comprehensive fishery monitoring activities during the Areas 5 and 6 mark-selective Chinook fisheries. The study designs used in the two areas during 2009, however, differed markedly from those previously employed (2003-2008). First, a scaled-back version (i.e., with fewer sites and days sampled) of the former dockside sample design (i.e., Intensive or “Murthy” [probability-based] sampling) was used to provide coarse in-season estimates of catch and effort for Area 5; to ensure that long-term fishery sampling targets were not compromised, this effort was accompanied by a high level of opportunistic Baseline Sampling. In addition, 2009 was the first season in which we did not operate a test fishing vessel in Area 5. The Area 6 design consisted of Baseline angler/catch sampling only and therefore did not have an on-the-water (i.e., boat surveys, test fishing) sampling component1. In both Areas 5 and 6, we employed an enhanced Voluntary Trip Report (VTR) program to obtain estimates of Chinook encounter rates by size class (legal or sub-legal) and mark status (ad-marked or unmarked), similar to our approach used successfully during summer 2008. For the enhanced VTR program, an additional WDFW technician was hired to work exclusively on distributing and collecting VTRs from the angling public.
Area 5 sampling activities included dockside creel sampling (Intensive and Baseline), on-the-water effort surveys, and the enhanced Voluntary Trip Report distribution and collection efforts. Among other parameters, Area 5 efforts emphasized data collection needs for the estimation of: i) the mark rate of the targeted Chinook population (based on VTRs), ii) the total number of Chinook salmon harvested (by size [legal or sublegal] and mark-status [marked or unmarked] group), iii) the total number of Chinook salmon released (by size/mark-status group), iv) the coded-wire tag- (CWT) stock composition of marked and unmarked Chinook mortalities2, and v) the total mortality of marked and unmarked double index tag (DIT) CWT stocks. The Area 6 design provided data for the estimation of: i) mark rates (based on VTRs), ii) indices of Chinook salmon encounters and angling effort (i.e., sample-frame observations, not fishery totals), and iii) the age, length, and CWT composition of landed catch.
Area 5 Summary
For in-season catch and effort estimation, creel samplers staffed two of six possible sites in our sample site frame (Olson’s Resort-East Docks, Olson’s Resort-Ramp and Docks, Olson’s Resort-West Docks, Van Riper’s North Docks, Van Riper’s South Docks, and Curley’s/Straitside Resort) on each sampling day, for a grand total of 35 site-days during the 37 days that Area 5 was open to Chinook retention under mark-selective regulations. Additionally, Baseline sampling occurred at two primary sites (Olson’s and Van Riper’s Resorts; includes sub-sites), resulting in an additional 32 site-days of sampling. In combination, these sampling efforts allowed us to directly sample 5,647 completed angler trips and 2,320 completed boat trips during Intensive sampling; Baseline efforts yielded an additional 1,075 boat trip and 2,548 angler trip observations. For all dockside angler interviews combined, we obtained samples from 1,699 Chinook salmon harvested (1,158 from Intensive; 541 from Baseline) during the July 1 – August 6, 2009 mark-selective Chinook fishery in Area 5. In addition, PSSU staff conducted 3 on-the-water effort surveys (2 weekday, 1 weekend) in support of Area 5 monitoring efforts.
Based on the combination of dockside and on-the-water sampling activities, we estimated that 23,662 angler trips were completed in Area 5 between July 1st and August 6th. Landing a grand total of 6,397 estimated Chinook (5,958 marked and 439 unmarked) during the fishery, these anglers experienced a season-wide CPUE of 0.26 Chinook retained per angler trip. Additionally, anglers released an estimated 31,065 Chinook (10,546 marked, 20,519 unmarked) over the season.
During the thirty-seven-day Area 5 fishery, harvested Chinook averaged 64 cm (range: 39 to 103 cm) in total length and were larger than the legal minimum size limit (>22 in or 56 cm TL) in the majority instances (dockside marked Chinook observations, >81% of legal size). Further, for marked and unmarked Chinook combined, the majority (57%) of all harvested individuals were 3-year olds (i.e., brood year 2006).
In addition, ramp samplers recovered 259 CWTs from marked Chinook harvested in Area 5. The majority of these recoveries (56%) were from Columbia River production facilities; a single Columbia River tag group accounted for 23% (62 tags) of the sample. The remaining CWTs were from Puget Sound (24%), Hood Canal (8%), Canada (5%), Upper Skagit River (3.5%), Oregon coastal (1.2%), California coastal (1.2%), and Washington coastal (0.8%) production facilities.
Although we did not test fish in Area 5 in 2009, we estimated the size/mark-status composition of encountered Chinook using results from our angler-submitted VTRs. Over the entire Area 5 season, anglers who submitted VTRs encountered 572 Chinook salmon, 44% of which were marked (all sizes) with 47% of the legal-sized encounters marked. With a “CPUE” (legal-marked Chinook encounters / angler trip) of 0.24, VTR anglers encountered legal-marked Chinook at approximately the same rate as the private recreational fleet. For the 37-day season, we estimated the size/mark-status composition at 15% legal-marked (LM), 17% legal-unmarked (LU), 29% sublegal-marked (SM), and 39% sublegal-unmarked (SU).
The 2009 Area 5 VTRs (n = 572 Chinook encounters) provided information on 11.4 times as many encounters as did the Area 5 test fishery in 2008 (n = 50), and, on average, 6.4 times more encounters than the average test fishery sample size during the 2003-2007 seasons (average n = 89; range: 80-335). Furthermore, the sample size of Chinook encounters from VTRs in 2009 was 4.2 times higher than the sample size from VTRs in 2008 (n = 135), the first year of our enhanced VTR program.
By combining dockside-sampling results (i.e., legal-marked Chinook harvest estimates) and VTR encounters data, we generated size/mark-status group-specific estimates of encounters and mortalities for Area 5. In total, an estimated 37,463 Chinook were encountered (retained and released) during the Area 5 fishery, with 5,567 of these being legal-marked, 6,287 legal-unmarked, 10,937 sublegal-marked, and 14,671 sublegal-unmarked individuals. Among released encounters, an estimated 109 legal-marked, 931 legal-unmarked, 1,965 sublegal-marked, and 2,862 sublegal-unmarked Chinook (5,866 overall) were estimated to have died due to handling and release effects of the Area 5 fishery. Thus, in total, 8,031 marked (74% due to direct harvest) and 4,232 unmarked Chinook mortalities occurred as a result of the fishery. Overall, field estimates of encounters were higher than pre-season expectations (i.e., Fishery Regulation Assessment Model results [FRAM, model run 2309]) for legal-marked Chinook salmon; substantial differences, however, were documented for other size/mark-status groups. Specifically, sublegal and/or unmarked Chinook encounter estimates were considerably higher than expected based on pre-season FRAM runs.
Finally, regarding impacts of the Area 5 fishery on the coded-wire tag (CWT) program, we estimated that 25 unmarked Chinook belonging to double-index tag (DIT) groups may have died due to this MSF.
Area 6 Summary
From July 1st through August 6th, 2009, samplers conducted Baseline sampling at three different sites (Freshwater Bay, Port Angeles West Ramp, and Port Angeles Public Ramp-Ediz Hood) used to access the Area 6 MSF. As a result, samplers acquired catch (kept and released) and effort information on 1,949 completed angler trips. Over all interviews, ramp samplers observed 539 harvested Chinook (all marked) and recorded 750 angler-reported Chinook releases (168 marked, 418 unmarked, and 164 of unknown mark status). Given these observations, we estimated the season-wide Area 6 CPUE at 0.28 Chinook retained per angler trip.
During the thirty-seven-day Area 6 fishery, harvested Chinook averaged 77 cm (range: 47 to 104 cm) in total length and were larger than the legal minimum size limit (>22 in or 56 cm TL) nearly all instances (8 sublegal fish [1.4%] were harvested). Sixty-two percent of all harvested individuals were 4-year olds (i.e., brood year 2005), with the majority of the remaining individuals being age-3 fish (35%).
In addition to collecting length data and scales, ramp samplers recovered 16 CWTs from marked Chinook harvested in Area 6, two-thirds of which were from Central Puget Sound facilities. Outside of Puget Sound tag groups, four tags were recovered from Hood Canal tag groups. A total of 8 (50%) of the recovered CWTs were associated with double index tag (DIT) groups.
Although we did not test fish in Area 6 in 2009, we acquired data on the size/mark-status composition of encountered Chinook using results from our angler-submitted VTRs. In total, we received a total of 89 VTRs from participating anglers which provided data on 192 Chinook encounters. From the VTR response, we estimated that 66% of all Area 6 Chinook encounters were marked, while 69% of legal-sized encounters were marked. Twenty-two (11%) of the total Chinook encounters were sublegal in size.
1 The Area 6 fishery was monitored using a reduced, Baseline sampling approach. While this approach does not provide a means for generating in- or immediately post-season estimates of fishery total catch and effort, these sampling observations will be combined with catch record card data to obtain these values at a later time.
2 In the present report, CWT-based (unexpanded) estimates of the stock composition of marked Chinook harvest are provided.