Fishing / Shellfishing - Selective Fishing
Date Published: June 21, 2010
Number of Pages: 64
Author(s): Mark Baltzell, Steve Caromile, and Laurie Peterson
Background and Overview
The Washington Department of Fish and Wildlife (WDFW) implemented mark-selective Chinook fisheries (MSFs) in Marine Areas 11 (June 1-September 30) and 13 (May 1-September 30) for the third time during the summer of 2009. 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.
WDFWâ€™s Puget Sound Sampling Unit (PSSU) implemented an intensive monitoring program in Area 11 in order to collect the data needed to provide in-season catch estimates and to estimate key parameters characterizing the fishery and its impacts on unmarked salmon. Area 11 sampling activities included dockside creel sampling, test fishing, on-the-water effort surveys, and intensive efforts to distribute and collect voluntary trip reports (VTRs) from the angling public. Among other parameters, Area 11 efforts emphasized data collection needs for the estimation of: i) the mark rate of the targeted Chinook population, 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) and/or DNA-based stock composition of marked and unmarked Chinook mortalities1, and v) the total mortality of marked and unmarked double index tag (DIT) CWT stocks. In contrast, a reduced sampling program was employed in Area 13 for logistical reasons. Area 13 monitoring activities included sampling for the estimation of: i) mark rates (based on voluntary trip reports provided by private anglers), 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 11 Summary
Creel samplers staffed six different access sites (two on any given sampling day) on 140 site-days during the four months (June 1 through September 30, 2009) that Area 11 was open to Chinook retention under mark-selective regulations. Samplers interviewed an estimated 18% of all anglers fishing in the area (n = 14,663 anglers). Additionally, they sampled an estimated 26% (n = 852) of all marked Chinook harvested during the fishery. Other PSSU staff conducted 17 on-the-water effort surveys (9 on weekdays, 8 on weekends), and spent 80 days (448 hours) on the water pursuing Chinook using test-fishing methods, in support of Area 11 monitoring efforts.
Based on the combination of sampling activities, we estimated that 80,715 trips were completed by Area 11 anglers between June 1st and September 30th. With a season-wide CPUE of 0.04 Chinook retained per angler trip, these anglers harvested a grand total of 3,277 marked Chinook during the fishery. Anglers additionally released an estimated 8,892 Chinook (4,305 marked, 4,587 unmarked). Overall, 2009 catch rates for Chinook (retained Chinook per angler trip) were lower than those observed in Area 11 during the summers of 2007 and 2008 (WDFW 2007b and 2009c). Effort levels (estimated angler trips) in Area 11 were similar in 2009 compared to 2008.
During the four-month Area 11 fishery, harvested Chinook averaged 76 cm (range: 37 to 99 cm) in total length and were larger than the legal minimum size limit (>22 in or 56 cm TL) in most instances (dockside marked Chinook observations, 96% of legal size). Further, more than half of all harvested individuals were 4-year olds (i.e., brood year 2005). In addition to taking length measurements and scale samples, ramp samplers recovered 63 CWTs from marked Chinook harvested in Area 11. The majority of these recoveries (63%) were from Hood Canal and Central Puget Sound facilities, primarily Voights Creek and Hoodsport hatcheries.
Over the entire Area 11 season, test fishers encountered 43 Chinook salmon, 86% of which were marked (all sizes) and 84% of which were of legal size (ad-marked and unmarked fish combined). With a â€œCPUEâ€ (legal-marked Chinook encounters / angler trip) of 0.17, test fishers encountered legal-marked Chinook at a substantially higher rate than did the private recreational fleet. Test-fishery Chinook total lengths averaged 67 cm (marked and unmarked mean; range: 33-90 cm). For the four-month season combined, we estimated the size/mark-status composition of the test fishery to be 63% legal-marked (LM), 12% legal-unmarked (LU), 23% sublegal-marked (SM), and 2% sublegal-unmarked (SU).
Over the entire Area 11 season, fleet anglers returned 389 VTRâ€™s, representing 701 angler trips and 689 Chinook encounters. With a season-wide average CPUE of 0.28 legal-marked Chinook/angler trip, VTR anglers encountered Chinook at a greater rate than both test fishers and the recreational fleet. For the four-month season combined, we estimated the size/mark-status composition from the VTRâ€™s to be 30% legal-marked (LM), 11% legal-unmarked (LU), 32% sublegal-marked (SM), and 27% sublegal-unmarked (SU).
By combining dockside-sampling results (i.e., legal-marked Chinook harvest estimates) and VTR-based encounters data (due to high VTR sample sizes compared to test fishery data), we generated size/mark-status group-specific estimates of encounters and mortalities for Area 11. In total, 12,205 Chinook were encountered (retained and released) during the Area 11 fishery, with 3,631 of these being legal-marked, 1,293 legal-unmarked, 3,950 sublegal-marked, and 3,330 sublegal-unmarked individuals. Among released encounters, an estimated 71 legal-marked, 191 legal-unmarked, 767 sublegal-marked, and 663 sublegal-unmarked Chinook (1,691 overall) were estimated to have died due to handling and release effects of the Area 11 fishery. Thus, in total, 4,114 marked (80% due to direct harvest) and 891 unmarked Chinook mortalities occurred as a result of the Area 11 MSF. Overall, estimated impacts were similar to (unmarked mortalities) or considerably less than (marked encounters or mortalities) what was expected based on pre-season Fishery Regulation Assessment Model runs (model run
2309). Finally, regarding impacts of MSFs on the coded-wire tag (CWT) program, we estimated that as many as 10 unmarked Chinook belonging to double-index tag (DIT) groups may have died due to the handling-and-release impacts of the Area 11 MSF.
Area 13 Summary
Between May 1st and September 30th, 2009, samplers conducted Baseline sampling2 at 23 different sites used to access the Area 13 MSF. As a result, samplers acquired catch (kept and released) and effort information on 2,149 completed angler trips. Over all interviews, ramp samplers observed anglers harvest a total of 68 Chinook (67 marked, 1 unmarked) and recorded 117 angler-reported Chinook releases (47 marked, 18 unmarked, and 52 of unknown mark status). Given these observations, we estimated the season-wide Area 13 CPUE at 0.03 Chinook retained per angler trip, a value that was low in general and half of what was observed during 2008.
During the five-month Area 13 fishery, harvested Chinook averaged 76 cm (range: 40 to 98 cm) in total length and were larger than the legal minimum size limit (>22 in or 56 cm TL) in most instances (94% of marked fish). Further, 49% of all harvested individuals were 4-year olds (i.e., brood year 2005), while 43% were 3-year olds. In addition to collecting length data and scales, ramp samplers recovered three CWTs from marked Chinook harvested in Area 13, all of which were from South Puget Sound facilities.
Though we did not test fish in Area 13 during its mark-selective Chinook season, we estimated the overall and legal-sized mark rate based on angler-supplied voluntary trip reports (VTRs). In total, 18 separate VTRs were returned, providing size/mark-status details on 36 individual Area 13 Chinook encounters. VTR-supplied data, in combination with dockside interview results, suggest that high (i.e., 60-70%) mark rates were present throughout the Area 13 mark-selective Chinook fishery.
1 Though the necessary tissue samples have been collected, DNA-based estimates of stock composition are presently unavailable for Puget Sound/Strait of Juan de Fuca mark-selective fisheries. In the present report, CWT-based (unexpanded) estimates of the stock composition of marked Chinook harvest are provided.
2 The Area 13 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 (i.e., CPUE) will be combined with catch record card (CRC) data to obtain these values at a later time.
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