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Fishes of the Yellowstone to Yukon Region Technical Report #3 By: David W. Mayhood December 2007 David W. Mayhood FWR Freshwater Research Limited and Yellowstone to Yukon Conservation Initiative Cover photograph by Florian Schulz Cutthrout (Oncorhynchus clarki); A native fish species in the Y2Y region www.visionsofthewild.com Technical Report #3 April 2007 Fishes of the Yellowstone to Yukon Region David W. Mayhood 1240 Railway Avenue, Unit 200 Canmore, Alberta T1W 1P4 (Printed on recycled materials) FISHES OF THE YELLOWSTONE TO YUKON REGION i FOR MORE INFORMATION CONTACT: Yellowstone to Yukon Conservation Initiative 1240 Railway Avenue, Unit 200 Canmore, Alberta T1W 1P4 Canada Telephone: (403) 609-2666 Fax: (403) 609-2667 Available for download from http://www.y2y.net SUGGESTED CITATION: Mayhood, David W. 2007. Fishes of the Yellowstone to Yukon Region. Yellowstone to Yukon Conservation Initiative, Canmore, Alberta, Technical Report #3, December 2007. COPYRIGHT: The contents of this paper are solely the property of the Yellowstone to Yukon Conservation Initiative and David W. Mayhood, and cannot be reproduced without permission from both parties. DISCLAIMER: This report is solely the work of its author, David W. Mayhood, and may or may not represent the views of the Yellowstone to Yukon Conservation Initiative. It has been edited for style and English usage, but its scientifi c content has not been peer-reviewed, and therefore does not constitute a publica- tion for scientifi c purposes. For written permission to reproduce this publication in whole or in part, please contact the author through http://fwresearch.ca. FISHES OF THE YELLOWSTONE TO YUKON REGION ii Preface The Yellowstone to Yukon Conservation Initiative’s (Y2YCI) goal is to restore and maintain biological diversity and landscape connectivity in the Cordilleran region of western North America. The region’s diverse fi sh fauna is a key component of this biodiversity. Maintaining the distribution of native fi sh populations is a critical issue in regional conservation and management. To provide a basis for addressing fi sh conservation in the Yellowstone to Yukon (Y2Y) region, historical and current lists of fi sh species occurrences were compiled for the 297 sub-basins comprising the Y2Y region. A cluster analysis was used on the presence-absence data to identify four natural faunal groups. These groups were explicable on the basis of their long geographic isolation and glacial-postglacial history, consistent with existing published zoogeographic analyses. The Arctic Interior Glaciated faunal group (Group 1) occupies the basins glaciated during the Wisconsinan glacial episode, and lies in Arctic drainages mostly east of the Continental Divide or within the Yukon River drainage (with one exception being the upper Stikine drainage). This group is derived primarily from the post-Wisconsinan invasion from refugia south and northwest of the Laurentide ice sheet. The Pacifi c Glaciated faunal group (Group 2) occupies four watersheds and watershed groups on the North Pacifi c coast west of the Continental Divide and south of the Yukon drainage. This faunal group has few species, most of which invaded post- glacially via the Pacifi c Ocean. The Pacifi c Columbia Refugium faunal group (Group 3) occupies most of the basins in the Y2Y region west of the Continental Divide. Most of this fauna survived the Wisconsinan maximum near or within this region south of the Cordilleran Ice Sheet, invading its northern glaciated basins post-glacially via interior routes and from the Pacifi c Ocean. The Interior Unglaciated faunal group (Group 4) occupies basins both west and east of the Continental Divide, and south of the Cordilleran and Laurentide Ice Sheets. Most of its fauna survived the Wisconsinan maximum more or less in place. At present, this entire region and the southern basins of the Pacifi c Columbia faunal group are occupied by a distinct artifi cial faunal group (Group 5) characterized by numerous widespread transplanted and non- native species, especially salmonids and centrarchids. Similarity analysis of historical and present faunal composition demonstrates increased homogenization of fi sh faunas within faunal Group 5, but greater dissimilarity among faunas within Group 3 as a result of fi sh introductions and extirpations. Within Group 1, some pairs of basins became more similar, while others became less similar after fi sh introductions and extirpations. The greatest opportunities for protection of intact, largely uncontaminated fi sh faunas lie in the drainages of Group 2 and the most northerly drainages of Group 1. The greatest conservation need and immediate challenges, however, occur in the drainages of Group 5 in the southern one- third of the study area, where faunal composition, catchments, hydrology and water quality are highly modifi ed. Specifi c recommendations are presented for dealing with data limitations, and for planning fi sh conservation activities by Y2YCI. FISHES OF THE YELLOWSTONE TO YUKON REGION iii Acknowledgments Rich Walker prepared the initial fi sh distribution table for the United States portion of the study area, which formed the basis for the updated version used in this paper. Rob Ament contributed to an earlier analysis, the data for which was used here, dealing with selected species only. Bill Haskins provided geographic information system (GIS) support, and the sub-basin base map for the study area. Marcy Mahr managed the project for the Yellowstone to Yukon Conservation Initiative. Numerous colleagues supplied data on fi sh distribution from their own fi eld work and observations over a period of many years; others went out of their way to supply hard-to-obtain manuscript reports and fi le data. In this respect I am particularly indebted to R. S. Anderson, A. Colbeck, D. Donald, L. Fitch, S. Herman, K. Brewin, G. Haas, C. Hunt, T. Hurd, J. Kilistoff, M. Kraft, P. McCart, C. Pacas, J. Paczkowski, M. Pole, D. Radford, J. Rennels, L. Rhude, J. Stelfox, C. Ward, W. Westover, and D. Wig. Cynthia Lane, Nancy Ouimet, and Joanne Kadi of the Yellowstone to Yukon Conservation Initiative provided editorial assistance. The study as organized here was funded by the Wilburforce Foundation through a grant to the Yellowstone to Yukon Conservation Initiative; however, data used in the project were compiled over many years, primarily while the author was funded by Parks Canada. FISHES OF THE YELLOWSTONE TO YUKON REGION iv Table of Contents Introduction .................................................................................................................................................................. 1 Study Area .................................................................................................................................................................... 2 Methods ......................................................................................................................................................................... 4 Analysis ......................................................................................................................................................................... 7 Results ........................................................................................................................................................................... 8 Overview .......................................................................................................................................................... 8 Cluster Analysis .............................................................................................................................................. 15 Similarity Analysis ......................................................................................................................................... 18 Discussion.................................................................................................................................................................... 21 Zoogeography ................................................................................................................................................. 21 Changes in the Fish Fauna .............................................................................................................................. 22 Conservation Goals ........................................................................................................................................ 23 Recommendations ...................................................................................................................................................... 25 Data Limitations ............................................................................................................................................. 25 Conservation Action ....................................................................................................................................... 25 References ................................................................................................................................................................... 27 Appendix ..................................................................................................................................................................... 33 Appendix A. Distribution and status of fi shes in the major drainage basins of Y2Y ......................................33 FISHES OF THE YELLOWSTONE TO YUKON REGION v Figures Figure 1. The 23 major