Fishing / Shellfishing - Selective Fishing
Date Published: February 23, 2009
Number of Pages: 47
Author(s): Mark Baltzell, Pete McHugh, and Laurie Peterson
The Washington Department of Fish and Wildlife (WDFW) implemented a winter mark-selective Chinook fishery (MSF) in Marine Area 10 for the first time, from December 1, 2007 through January 31, 2008. 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 this pilot fishery was to provide meaningful opportunity to the recreational angling public while minimally impacting ESA-listed Puget Sound Chinook salmon. WDFWes Puget Sound Sampling Unit (PSSU) implemented an intensive monitoring program in Area 10 throughout the fishery in order to collect the data needed to estimate key parameters characterizing the fishery and its impacts on wild salmon. Sampling activities included dockside creel sampling, test fishing, and on-the-water effort surveys. Among other parameters, 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 and 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.
Creel samplers staffed a total of five different access sites on 41 of the 61 days that Area 10 was open under mark-selective harvest regulations. Samplers interviewed an estimated 20% of all participating anglers (n = 523 angler trips) and sampled 22% of all marked Chinook harvested (n = 140). Additionally, PSSU staff conducted six angler effort surveys (boat), and spent 21 days (96 hours) on the water pursuing Chinook using test fishing methods, in support of Area 10 monitoring efforts. Based on these efforts, we estimated that 2,544 angler trips were completed by a combination of private fleet and charter anglers during the fishery. With a CPUE of 0.25 Chinook landed per angler trip, these anglers harvested a grand total of 635 marked and 21 unmarked Chinook; they released an estimated 2,464 Chinook (1,940 marked and 524 unmarked). Harvested Chinook averaged 59 cm (range: 53 to 80 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, 116 legal /137 total or 85%). Most of the Chinook harvested were of brood year 2005 origin (i.e., age 2 fish in Dec. or age 3 fish in Jan.). In addition, 12 CWTs were recovered from harvested fish, all of which were from Puget Sound and Hood Canal release sites.
During their two months of sampling in Area 10, test fishers encountered 120 Chinook salmon, 26% and 66% of which were of legal size and marked, respectively. With a "CPUE" of 1.14 (LM Chinook encounters / angler trip), test fishers experienced a similar legal-marked Chinook encounter rate as did charter anglers. Chinook encountered by test fishers averaged 52.6 cm (range: 29 to 79 cm) in total length and were predominantly 2 and 3 years in age (98% of marked and 90% of unmarked totals). We estimated the overall mark rate at 83% (77% for legal-size Chinook only) and size/mark-status composition at 20.0% legal-marked, 5.8% legal-unmarked, 62.5% sublegal-marked, and 11.7% sublegal-unmarked.
By combining dockside sampling results (i.e., legal-marked Chinook harvest estimates), test fishery/VTR size/mark-status composition data, and charter census results, we generated size/mark-status group-specific estimates of encounters and mortalities. In total, 3,120 Chinook were encountered (retained and released) during the Area 10 fishery, with 619 of these being legal-marked, 184 legal-unmarked, 1,956 sublegal-marked, and 361 sublegal-unmarked individuals. Among released encounters, an estimated 12 legal-marked, 24 legal-unmarked, 372 sublegal-marked, and 72 sublegal-unmarked Chinook (481 overall) were estimated to have died due to handling and release effects. Thus, in total, 1,019 marked (62% due to direct harvest) and 117 unmarked Chinook mortalities occurred as a result of the Area 10 fishery. All Chinook impacts were less than expectations set by pre-season Fishery Regulation Assessment Model runs (model run 3907). The impact of the Area 10 fishery on unmarked Chinook was lower than half of what was anticipated. Finally, regarding impacts of MSFs on the coded-wire tag (CWT) program, we estimated that 3 unmarked Chinook belonging to double-index tag (DIT) groups may have died due to the handling-and-release impacts of the pilot Area 10 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.
Marine Area 10 Mark-Selective Recreational Chinook Fishery, January 16 – April 15, 2008 Post-season Report. Revised Draft: February 23, 2009. 47 pp. Washington Department of Fish and Wildlife. Olympia, Washington.