Koocanusa Reservoir Kokanee Spawner Index

Transcription

1 Koocanusa Reservoir Kokanee Spawner Index Authored by: Harald Manson Fisheries Biologist Updated by: Louise Porto MSc., RPBio. Fisheries Biologist Columbia Basin Fish & Wildlife Compensation Program Victoria St. Nelson, BC January 2006

2 EXECUTIVE SUMMARY This report summarizes results of the 2005 kokanee escapement survey conducted in Koocanusa Reservoir and its associated tributaries. Aerial counts were conducted on 3 and 5 October An estimated 115,760 spawning kokanee were enumerated in 11 index streams and rivers in the Koocanusa Reservoir drainage during the fall of The 2005 kokanee escapement index was 27% higher than the 2004 index, however, it was the second lowest recorded since It is recommended that kokanee escapement be monitored annually as a trend through time indicator of changes in adult kokanee abundance in Koocanusa Reservoir. KEYWORDS Koocanusa Reservoir, Kootenay, kokanee spawner index, aerial kokanee survey 2

3 TABLE OF CONTENTS PAGE EXECUTIVE SUMMARY... 2 TABLE OF CONTENTS... 3 INTRODUCTION... 4 METHODS... 4 RESULTS AND DISCUSSION... 4 RECOMMENDATIONS... 7 REFERENCES... 7 ACKNOWLEDGEMENTS... 7 Appendix A. Kootenay Kokanee Counts 3 and 5 October TABLE OF FIGURES Figure 1. Location of index streams used for kokanee aerial surveys in the Kootenay drainage in Figure 2. Koocanusa Reservoir kokanee escapement index, 1996 to TABLE OF TABLES Table 1. Number of spawning kokanee counted in selected tributary streams to the Kootenay, 1996 to

4 INTRODUCTION Kokanee were inadvertently introduced into Lake Koocanusa between 1970 and 1974 from the Kootenay Trout Hatchery at Wardner (Brown 1993). They have since become well established in the reservoir and are now highly sought after by anglers during the summer months. The first basin-wide survey of spawning kokanee in the upper Kootenay occurred in 1996 and involved twenty-eight streams (Westover 1997). Since 1999, portions of eleven index streams have been flown annually to provide trends in kokanee abundance. During the fall of 2005, B.C. Hydro partnered with the Columbia Basin Fish and Wildlife Compensation Program (CBFWCP), the BC Ministry of Environment (MoE), and the Freshwater Fisheries Society of BC (FFSBC) to conduct the ninth year of an aerial enumeration of spawning kokanee in tributaries to Koocanusa Reservoir and Kootenay. The objectives of the survey were to derive an abundance index from eleven candidate index streams. METHODS Kokanee in the Koocanusa Reservoir were enumerated on 3 and 5 October 2005 from a Bell 206 helicopter, which travelled between 16 to 30 km/hr at a height of approximately 50 metres above ground level. Two observers were present during the flight. Kokanee were grouped in schools of 50, 100, 500 individuals etc. and summed to provide two independent estimates (Appendix A). Information from Montana Department of Fish & Wildlife Parks (MDFWP) kokanee gill net program was not available for the present analysis (Manson 2005). RESULTS AND DISCUSSION An estimated 115,760 spawning kokanee were enumerated in 11 index streams and rivers in the Koocanusa Reservoir and Kootenay drainage during the fall of 2005 (Table 1). The Lussier followed by Norbury Creek contained the highest and second highest numbers of kokanee in the Koocanusa Reservoir, respectively. The estimated numbers of kokanee for the 11 index streams for the last 10 years (1996 to 2005) are shown in Table 1 and Figure 2. The 2005 kokanee escapement index was 27% higher than the 2004 index, however, it is the second lowest recorded since 1996 (Figure 2). 4

5 Findlay Creek Figure 1: Kokanee Spawner Aerial Surveys in the upper Kootenay Drainage ³ kilometers UTM zone 11 NAD 83 CBFWCP May 9, 2005 KOOTENAY Columbia Basin Fish and Wildlife Compansation Program Kokanee Spawner Aerial Survey Streams RIVER Lussier Kimberley Wildhorse St. Mary Cranbrook Kootenay Norbury Creek Bull Fernie Columbia Basin Fish & Wildlife Compensation Program Area Little Sand Creek Sand Creek Study Location LAKE KOOCANUSA Wigwam Elk Figure 1. Location of index streams used for kokanee spawner aerial surveys in the upper Kootenay drainage in

6 Table 1. Number of spawning kokanee counted in selected tributary streams to the Kootenay, Stream Bull 54,850 10,852 1,782 26,090 43,500 25,325 19,400 19,370 1,987 4,050 Elk 1, , Findlay Creek 1,405 2,010 1,120 9,100 6,180 6,475 9,050 1, ,200 Kootenay * 50,250 18,120 30,195 32,040 98,980 74,510 83,400 35, Little Sand Creek 7,250 3, ,402 13,050 2,450 37,000 2,400 3,580 5,700 Lussier 171,000 49,450 98, ,445 43, , ,650 32,220 15,000 52,180 Norbury Creek 11,800 11,050 9,340 7,902 47,500 23,300 19,800 21,550 12,270 27,350 Sand Creek 71,170 17, ,285 57,800 1,432 81,350 33,760 5,755 11,550 St. Mary 12,175 3,810 5,856 8,825 11,440 4,701 16,375 1, ,270 Wigwam 11, ,768 1, , ,910 Wild Horse 4, , , ,125 1,650 Total Number 397, , , , , , , ,330 40, ,760 * only includes the side channels by the city fields. Number 500, , , , , , , , ,000 50, Year Figure 2. Koocanusa Reservoir kokanee escapement index, 1996 to

7 RECOMMENDATIONS It is recommended that kokanee escapement be monitored annually as a trend through time indicator of changes in adult kokanee abundance in Koocanusa Reservoir. Annual aerial counts should be undertaken at the peak of the kokanee spawning run using the same pilots and observers each year. MoE should continue to permit MDFWP to conduct a kokanee gillnet index in the Canadian portion of Koocanusa Reservoir to monitor trend through time changes in kokanee growth and age at maturity. REFERENCES Brown, Peter Note to File: Koocanusa Kokanee Origins. Kootenay Trout Hatchery, B.C. Environment Fish Culture Section. Manson, H Koocanusa Reservoir kokanee spawner escapement Columbia Basin Fish & Wildlife Compensation Program. 10 pp + 2 App. Westover, W.T Koocanusa Kokanee Enumeration (1996) Ministry of Environment, Fisheries Branch, for Columbia Basin Fish and Wildlife Compensation Program, Nelson B.C. ACKNOWLEDGEMENTS The author would like to thank Laird Siemens for co-ordinating the aerial counts Doug Crowley and Diana Koller for conducting the aerial surveys. The author would also like to thank Steve Arndt for reviewing a draft of this report. The Columbia Basin Fish and Wildlife Compensation Program, and BC Hydro provided funding for the 2005 Koocanusa Reservoir kokanee spawner abundance index. 7

8 Appendix A. Kootenay Kokanee Counts 3 and 5 October 2004 Agreed Stream Section Total Elk Reservoir to Wigwam 700 Elk Wigwam to Elko Canyon 0 Wigwam Lower thru Canyon to Wigwam Flats Bridge 10 Wigwam Wigwam Flats Br. to Lodgepole Junction 3,900 Sand Reservoir to Creek Baynes Lake Road 4,650 Sand Baynes Lake Road Creek to Highway #3 6,900 Little Sand Sand Creek Creek to Highway #3 5,700 Bull Kootenay to Tie Mill Dam 1,700 Bull Tie Mill Dam to Aberfeldie 2,350 Norbury Kootenay Creek to Railway Culvert 27,000 Norbury Railway Culvert Creek to Hatchery Dam 350 Wildhorse Kootenay to Fort Steele Rd. 1,650 8

9 Agreed Stream Section Total St. Mary Wycliffe to Mark Creek 2,110 St. Mary Mark Creek to St. Mary Lake 4,160 Lussier Kootenay to Premier Bridge 34,680 Lussier Premier Bridge to Ram Creek Hot- Spring Bridge 5,700 Lussier Ram Creek Hot- Spring Bridge to 10-Mile Bridge 11,800 Findlay Kootenay Creek to Falls 2,200 Kootenay Side channel by City Fields 200 Counts done by: Doug Crawley and Diana Koller 9