Snake River Spring Chinook Salmon Fishery Report, 2005

The Snake River recreational chinook fishery opened June 11 and ran through June 30, 2005. The Snake River was open from the Texas Rapids boat launch upstream to the Corps of Engineers boat launch (approximately one mile) upstream of Little Goose Dam on the south bank of the river; referred to as the Little Goose (LGO) fishery in this report. The fishery was open seven days per week, with daily fishing hours set from one hour before sunrise to one hour after sunset. The daily limit consisted of one hatchery (adipose fin-clipped) chinook salmon (adult or jack) per day, with a minimum size of 12 inches. Anglers were required to use barbless hooks, with hooks of no more that 5/8 inch from point to shank.

The pre-season Snake River runsize estimate (entering the mouth of the Columbia River) was 128,100 spring/summer Chinook with about 23,400 (18%) estimated to be of wild origin. Preseason plans for the Snake River recreational chinook fishery was to harvest up to 2,132 hatchery adult spring chinook, with an allowable Endangered Species Act (ESA) impact of 47 wild fish mortalities (0.2% ESA impact on wild chinook estimated at Columbia River mouth). Assuming a 10% mortality rate on released fish, this allowed for 468 wild adult encounters. ESA impacts for this fishery are included as part of the non-Indian rate of 2.0% allowable impact which also includes recreational and commercial fisheries downstream. However, the run came in at a lower rate than expected from pre-season estimates. An in-season estimate in early June based primarily on counts at Bonneville Dam reduced the estimated Snake River spring/summer chinook run to approximately 39,700 fish (at Lower Granite Dam). We reduced the harvest target to 373 hatchery chinook adults and the encounter (or �"handle”) of wild chinook adults to 124. Total ESA impact for this fishery was expected to be 12 wild adult mortalities or an impact rate of approximately 0.17%.

The Washington Department of Fish and Wildlife monitored the fishery using a roving creel survey which included: boat ramp and shore interviews to collect catch rate, completed trip and biological information; and effort counts of shore anglers, boat anglers, and the number of boats (counts were done five times a day). Monitoring was conducted at least one weekday and one weekend day per 7 day period, utilizing a dawn to dusk survey format. Creel surveys were conducted on 7 days (3 weekend days and 4 weekdays) of the season. The 20 day fishery had 14 weekdays and 6 weekend days available. We sampled 50% of weekend days and 28.6% of weekdays. Survey data were summarized weekly to estimate kept catch and encounters (kept catch and fish released) and assure compliance with the ESA impact level that had been set for the fishery.

The fishery results were divided by �"spill” and �"no spill” segments. The no spill days were from June 11th through the 19th and also included June 30th. No spill days had much better fish movement through Little Goose Dam and therefore had better catch and release rates than spill days. June 30th was included as a no spill day because the proportion of spill to turbine flows was modified on that day and most of the fish that were pooled up below the dam passed on that day (Appendix A). We have also heard that the catch rate increased on the afternoon of the 30th although a creel survey was not conducted on that day. The major spill days were from June 20th through June 29th. During spill days the harvest and release rates were very poor, and fish passage at Little Goose Dam was very low (Appendix A).