Summary of the 2003 Mid-Columbia PUD Bull Trout Study Results through 27 August 2003

Detection Summary:

• This summary includes fixed-site telemetry data through 27 August 2003 at Rock Island, Rocky Reach, and Wells dams; as well as the fixed-telemetry sites on the Wenatchee, Entiat, Methow, and Okanogan rivers. It also includes aerial survey data through 12 August 2003 and boat survey data through 22 July 2003. To date, three boat and three aerial surveys have been conducted during the 2003-2004 study period. Table 1 summarizes the last known location of all radio-tagged bull trout as identified by release location.

• Monitoring of radio-tagged bull trout at the fixed-site telemetry systems at Priest Rapids and Wanapum dams concluded on 16 June 2003. Monitoring at those locations was conducted during Grant PUD’s radio-telemetry evaluation of smolt passage during the spring migration and concluded at the completion of that study. To determine if radio-tagged bull trout migrate downstream into the Grant PUD project area, we will rely on detections of tagged fish within the tailrace of Rock Island Dam.

• For the 2003-2004 study period, no new bull trout were captured and tagged. Instead, we continue to track fish tagged in May and June of 2002 (N = 40). Those fish were tagged with transmitters with an estimated tag life of two years, which should continue to operate until the completion of this study period (31 March 2004).

• Based on current telemetry data there are seven tagged bull trout in the mainstem Columbia River, four in the Wenatchee River basin, 15 in the Entiat River basin, eight in the Methow River basin, and six transmitters have been recovered (Table 1). No tagged trout have been detected in the Okanogan River.

• Of the seven tagged bull trout located within the mainstem of the Columbia River, one is downstream from Priest Rapids Dam, one was last detected in the tailrace of Rocky Reach Dam, four were last detected upstream of Rocky Reach Dam between the dam and the Entiat River confluence, and one was last detected in the tailrace of Wells Dam. The fish that is downstream from Priest Rapids Dam was last detected in the tailrace of that project on 28 May. Prior to that detection, it was detected at Rock Island Dam on 24 May and at Wanapum Dam on 26 May. Efforts to locate this fish have been unsuccessful.

• Of the four tagged fish in the Wenatchee River basin, one is in Ingalls Creek, a tributary to Peshastin Creek. The other three fish are in the Chiwawa River drainage; two residing in the Chiwawa River and one in Rock Creek, a tributary to the Chiwawa River.

• Of the 15 fish in the Entiat River basin, two were last detected between the mouth of the Entiat River and the Mad River confluence, five are upstream of Preston Falls, and eight are located within the Mad River.

• Of the eight fish detected in the Methow River basin, we last detected four in the mainstem Methow River (two between the mouth of the Methow River and Libby Creek, one between the confluences of Libby Creek and the Twisp River, and one upstream of the town of Winthrop) and four in the Twisp River, all of which are located upstream from the confluence of Buttermilk Creek.

• There are ten fish that have not changed their position for an extended period of time. We will attempt to locate these fish and determine their current status.

Recovered Transmitters:

• At this time, a total of six transmitters have been recovered from fish tagged in 2002. Of these fish, one was tagged at Rock Island Dam, one at Rocky Reach Dam, and four at Wells Dam. A detailed report summarizing their detection histories and the location of their recovery will be included with the 2002/2003 report which will be distributed in September. It should be noted that the recovery of a transmitter does not necessarily mean that the tagged fish died. Of the six fish for which the transmitters were recovered, only one carcass has been

Rocky Reach Project No. 2145 Bull Trout Study Update SS/4966 1 September 24, 2003 recovered. Furthermore, one fish was captured at Rocky Reach Dam during the 2002 tagging period that exhibited scars consistent with being tagged (e.g., surgical scar and a “star-shaped” scar where the tag exited the body). Based upon these observations, it appears that this fish lost its tag prior to being recaptured.

Downstream Migration:

• In consultation between Chelan County PUD and the U.S. Fish and Wildlife Service, related to operation of the new Rocky Reach surface collection system, the Service requested that the PUD monitor tagged bull trout during the 2003 upstream migration to assess whether or not any of the tagged fish migrated downstream of a given project after ascending the fish ladders at Rock Island or Rocky Reach dams. We refer to such behavior as “downstream movement”.

• We observed only one occurrence of “downstream movement” during the period 1 April to 27 August 2003, which encompasses most if not all of the period when bull trout are actively migrating upstream through the mainstem Columbia River. This happened on 15 June 2003. The fish was detected on 14 June in the tailrace of Rocky Reach Dam, where it ascended the ladder and exited the system the following day. Forty-four minutes after exiting the ladder, the fish entered and passed downstream through Unit 1. Prior to passing the dam, the fish was detected along the face of the powerhouse up to Unit 9, and also entered the surface collector briefly. After the downstream movement event, this fish was detected in the Wenatchee River near the town of Monitor at the fixed-telemetry site on 22 June 2003.

Table 1. The last known location of radio-tagged bull trout (N=40) for the period of 13 May, 2002 to 27 August, 2003 as identified by release location.

Location of Last Detection Hydroelectric Project Basin Below Columbia Recovered Release Location RIS RRH Wells Wen. Ent. Met. Okan. RIS1 River2 Tag Total RIS Tailrace 2 1 1 4 RIS Forebay 2 1 1 4

RRH Tailrace 2 7 1 1 1 12 RRH Forebay 1 6 3 1 11

Wells Tailrace 1 1 2 4 Wells Forebay 3 2 5 Totals: 011 41580 1 4 6 40

Notes: 1 This refers to any detections below the Rock Island tailrace (i.e., Wanapum pool or dam, and Priest Rapids pool or dam). 2 This refers to any detection during aerial or boat surveys within the mainstem Columbia, and excludes detections at dams.

Bull Trout Study Update Rocky Reach Project No. 2145 September 24, 2003 2 SS/4966