P U B L I C U T I L I T Y D I S T R I C T N O . 1 o f C H E L A N C O U N T Y P.O. Box 1231, Wenatchee, WA 98807-1231 • 327 N. Wenatchee Ave., Wenatchee, WA 98801 (509) 663-8121 • Toll free 1-888-663-8121 • www.chelanpud.org

Mid-Columbia Bull Trout Update

To: Mid-Columbia Bull Trout Study Interested Parties

From: Scott Kreiter (509)663-8121, Ext. 6352 [email protected]

Subject: Rocky Reach Project No. 2145: Summary of the 2001 Bull Trout Study Results through August 2001

Date: October 1, 2001

Background Tagging Summary:

• For the study period May 15 to July 13, 2001, we tagged and released 39 bull trout: 7 at Rock Island, 22 at Rocky Reach, and 10 at Wells Dam. Our goal was to capture and tag 10 trout at Rock Island, 20 at Rocky Reach, and 10 at Wells.

• The median length and weight of all tagged fish was 54.1 cm (range = 40.9-59.7 cm) and 1,750 grams (range = 850-2,500 grams), respectively.

• At both Rocky Reach and Wells dams, we released half the tagged fish upstream and half downstream from the dams. At , we released 3 fish downstream and 4 upstream from the dam.

• The average time to conduct the surgical procedure was 8.0 minutes; the average recovery time before transport was 13.5 minutes. The average transport time was 11.3 minutes.

• At the time of release, all fish appeared lively and healthy.

Detection Summary:

• As of August 31, we have detected no radio-tagged bull trout downstream from Rock Island tailrace (based on aerial surveys and fixed detection sites within Wanapum pool, at , and at ).

• Only one tagged bull trout ventured into the Okanogan River. Shortly after detection, that fish left the Okanogan and subsequently immigrated into the . During the aerial surveys on August 10 and 31, that fish was detected in the Twisp River (a tributary of the Methow River) near the upper end of the drainage.

COMMISSIONERS: Bob Boyd, Gary L. Montague, David Pflugrath, Barbara B. Tilly, James R. Wall GENERAL MANAGER: Roger A. Braden • Based on fixed-site telemetry data and aerial and boat survey data collected through August, all 39 radio-tagged bull trout have been detected.

• Based on last detections, 2 trout are in the mainstem near the mouth of the Wenatchee River, 1 at Rock Island Dam, 1 at Wells Dam, 6 in the Wenatchee River basin, 14 in the Entiat River basin, and 15 in the Methow River basin (Table 1).

• One of the two fish located near the mouth of the Wenatchee River recently emigrated from the Entiat River.

• The fish detected at Rock Island Dam died. We discovered the carcass in shallow water in the forebay near the northeast corner of an island. After tagging and release, the trout traveled upriver to and remained there for nine days. Thirteen days later, we discovered the trout in the Rock Island forebay. The cause of death is unknown.

• The one fish detected at Wells Dam had not been detected since July 8. Although it is unclear where this fish resided between July 8 and August 31, quite likely it was in the upper reaches of the Methow Basin.

• Of the 6 fish recently detected in the Wenatchee River basin, 1 was in Icicle Creek and 5 in the mainstem Wenatchee River.

• Of the 14 fish recently detected in the Entiat River basin, 9 were in the Mad River and 5 in the mainstem Entiat River.

• Of the 15 fish recently detected in the Methow River basin, 1 was in Libby Creek (a tributary to the Methow River), 2 in Buttermilk Creek (a tributary to the Twisp River), 9 in the Twisp River, and 3 in the mainstem Methow River.

• As of the end of August, we have conducted five boat and five aerial surveys. Three aerial surveys were cancelled because of forest fires and FAA restrictions resulting from terrorism. We also canceled three boat surveys because of the small number of tagged bull trout in the mainstem Columbia River.

Location of Last Detection Hydroelectric Project Tributary Below Columbia Not Release Location RIS RRH Wells Wen. Ent. Met. Okan. RIS1 River2 Detected Total RIS Tailrace 1 2 3 RIS Forebay 1 2 1 4

RRH Tailrace 6 4 1 11 RRH Forebay 8 3 11

Wells Tailrace 4 1 5 Wells Forebay 5 5 Totals: 10161415002039

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

Table 1. The last known location for the 39 bull trout tagged during the period of May 15 to August 31 by release location.

Rocky Reach Project No. 2145 Bull Trout Study Update SS/3093 Page 2 October 1, 2001