Fishing / Shellfishing - Selective Fishing
Date Published: January 14, 2005
Number of Pages: 41
Author(s): Steven L. Thiesfeld and Angelika Hagen-Breaux
During the summer of 2004, the second year of a pilot recreational Chinook salmon Oncorhynchus tshawytscha (“Chinook”) fishery that was limited to retention of marked (adipose clipped) hatchery Chinook salmon occurred in Marine Area 5 and the western portion of Marine Area 6 in Puget Sound. Objectives were: 1) increase meaningful recreational opportunity while meeting conservation goals for Puget Sound Chinook salmon defined by the Puget Sound Chinook Harvest Management Plan; and 2) collect information necessary to enable evaluation and planning of future potential Chinook mark-selective fisheries. Marine Areas 5 and 6 are located in Washington waters of the Strait of Juan de Fuca. The Chinook Selective Fishery was scheduled to begin on July 1, 2004 and continue through August 10 (41 days) or until a quota of 3,500 Chinook was kept, whichever occurred first. The fishery started on July 1, 2004 and ran continuously for 39 days through August 8.
We estimated that anglers made 29,425 trips during the Chinook Selective Fishery (July 1 – August 8). Those anglers kept an estimated 3,576 Chinook and 9,537 coho salmon O. kisutch (“coho”). Area 5 accounted for 86% of the effort (25,174 angler trips) and 81% of the Chinook kept (2,900) for a rate of 0.12 Chinook kept per angler trip. Area 6 accounted for 4,251 angler trips and 676 Chinook kept for a higher catch rate of 0.16 Chinook kept per angler trip. Based on creel surveys, Area 5 anglers released an estimated 12,392 Chinook, 25,800 coho, and 113 other or unidentified salmon. Area 6 anglers released an estimated 1,409 Chinook, 126 coho, and 3 other or unidentified salmon.
During the Chinook Selective Fishery (July 1-August 8), samplers fishing from the test boats landed 169 Chinook in Area 5 and 148 Chinook in Area 6. In Area 5, 92% of the Chinook encountered and landed by the test boat were caught using downriggers, even though they were only fished 69% of the time. In Area 6, all the Chinook encountered and landed by the test boat were caught using downriggers, even though they were only fished 78% of the time. Utilizing other gear types resulted in fewer encounters and fewer biological samples for both areas than would have occurred if the test boats had used downriggers exclusively as they did in 2003.
During the Chinook Selective Fishery time period, 44% of the legal-size fish caught by test boats were marked in Area 5 and 48% of the legal-size Chinook were marked in Area 6. The mark rate on sublegal-size Chinook was 36% (n=59) for Area 5, but only five sublegal-size Chinook were caught by the test boat in Area 6. Chinook caught on test boats were larger in Area 6 than in Area 5. The percent of legal-size chinook (22” or larger) was significantly different (X2 = 49.8, p< 0.0001) between Area 6 (97%) and Area 5 (65%).
During the 2004 Chinook Selective Fishery only 35 Chinook were reported landed in Area 5 on Voluntary Trip Reports (VTR’s) turned in by anglers, while 112 Chinook were reported landed on VTR’s in Area 6. During the Chinook Selective Fishery time period, 40% of the legal-size Chinook were reported as marked in Area 6, which was lower than the mark rate from test fishing.
Twenty-nine double index coded wire tags were recovered in Areas 5 and 6 from July 1 through August 8. Based on the proportion of the catch that was sampled and the ratio of marked to unmarked double index coded wire tagged Chinook for each hatchery, we estimated that anglers caught and released 95 legal-size, unmarked double index tagged Chinook, and that the additional mortality of unmarked legal-size double index tagged Chinook due to this selective fishery compared to a non-selective fishery was 10 fish.
Test boat catches consistently showed a higher mark rate than reported from the creel survey and the VTR’s. We felt the mark rates from the test boats were the best estimate of the true mark rate. Using the total number of Chinook encounters from the creel survey (17,377) and apportioning into four categories of legal-size marked, legal-size unmarked, sublegal-size marked, and sublegal-size unmarked based on test fishing results, suggests that anglers released 1,834 legal-size and marked Chinook, or 34% of the fish they could have kept. We also estimated the number of encounters by assuming that anglers kept all Chinook that were legalsize and marked, and estimating the number of fish in the other three categories based upon the proportions they were caught in the test boats. Using this method, we estimated the total encounters at 11,481 Chinook. It appears unrealistic that anglers released one-third of the fish that were legal to keep, and it is also unrealistic that all legal fish were kept. The true number of encounters likely lies between the two estimates of encounters, i.e. between 11,481 and 17,377 Chinook.
Using the encounters from the creel survey (apportioned by category based on test fishing) and a release mortality rate of 15% for legal-size fish and 20% for sublegal-size fish, we estimated the total mortalities of Chinook in the selective fishery at 5,870, of which 1,676 were unmarked. Using the encounters estimated by assuming anglers kept all legal fish and a release mortality rate of 15% for legal-size fish and 20% for sublegal-size fish, we estimated total mortalities at 4,910 fish, of which 1,109 were unmarked fish.
Based on the estimated number of total encounters from the creel survey (the highest number) and apportioning them based on the test boat catch rates, we estimated the 2004 fishery encountered 7,498 unmarked legal-size Chinook and 1,738 unmarked sublegal-size Chinook. These estimates are below the predicted encounters of 7,993 unmarked legal-size Chinook and 4,935 unmarked sublegal-size Chinook as produced in the final pre-season run of the Fishery Regulation Assessment Model (FRAM).
Compliance with existing regulations, and the regulation prohibiting bringing unmarked salmon on board a vessel, was considered an integral part of a successful fishery. No citations or warnings were issued for retention of unmarked Chinook, nor were any warnings or citations issued for bringing an unmarked salmon on board a vessel.
In summary, the second year of the pilot marine Chinook selective fishery was successful with respect to the objective of increasing meaningful recreational opportunity within conservation constraints for Puget Sound Chinook. Anglers were allowed to fish for and retain Chinook for 39 days in Areas 5 and 6, compared with only 10 days and 5 days in Area 5 in 2001 and 2002, respectively. Angler effort in Area 5 was double the effort in 2002 during the same time frame. Using data from the test fishery sampling during the Chinook Selective Fishery, nearly half, or one in two, of the legal-size Chinook encountered were marked and could be retained by anglers. The pilot fishery was also successful with respect to the objective of implementing monitoring and sampling programs to obtain management information for evaluation and planning of potential future selective Chinook fisheries. Estimated encounters were less than pre-season predictions. Compliance with fishing regulations was good during the fishery. The number of mortalities of unmarked double index coded wire tagged fish was negligible.
2004 Chinook Selective Fishery, marine areas 5 and 6. January 12, 2005. Steven L. Thiesfeld and Angelika Hagen-Breaux. 2005. Washington Department of Fish and Wildlife. Olympia, Washington.