Action Plan to Conserve Bull Trout in Glacier National Park

Fredenberg, Wade; Meeuwig, Michael; Guy, Christopher

In 2003 the U.S. Fish and Wildlife Service, Glacier National Park, and the U.S. Geological Survey Montana Cooperative Fishery Research Unit collaborated to begin a research project that would examine all the bull trout resources in the Flathead River Basin (i.e., west side) portions of the Park in Montana. The first two objectives of the research project were accomplished and the scientific results are reported by Meeuwig and Guy (2007) as well as in condensed form in the research summary supplement to this report. The primary purpose of this report is fulfilling the third objective of the proposal (i.e., develop a comprehensive action plan for bull trout in Glacier National Park). Only about 100 lakes in the contiguous United States contain native adfluvial bull trout populations and only about half of those are in naturally functioning, undammed ecosystems. Comprehensive and recent status information for bull trout in Glacier National Park waters was notably lacking. This report describes 17 such waters along the western flanks of the Glacier National Park, representing an important and irreplaceable portion (approximately one-third) of the remaining natural lacustrine habitat supporting the adfluvial life history of bull trout. This report is organized to facilitate stand-alone use of the action plan by Glacier National Park staff members that may not necessarily be fisheries scientists. Within the action plan we have grouped the 17 lakes that were assessed into three threat categories: 1) secure lakes [Upper Kintla, Trout, Arrow, Isabel, and Upper Isabel, 2) vulnerable lakes [Akokala and Cerulean], and 3) compromised lakes [Kintla, Bowman, Quartz, Middle Quartz, Lower Quartz, Logging, Rogers, Harrison, McDonald, and Lincoln]. Secure lakes are all relatively small backcountry lakes with the documented presence of fish passage barriers in their drainages downstream. As a result, we consider these five lakes to have the most secure populations of bull trout on the west side of the Park. Consequently, the management emphasis for these lakes should be on long-term maintenance of current conditions. Vulnerable lakes are grouped together because we believe there is a high likelihood that they could become compromised from potential invasion by nonnative Salvelinus spp. (i.e., lake trout and/or brook trout). Unlike the secure lakes, we did not document the presence of any physical structures that would preclude fish passage in the drainages downstream from these vulnerable lakes. As a result, we consider the vulnerable lakes to be among the most at-risk populations of bull trout in the Park and the management emphasis should be on active evaluation of methods to maintain or improve the status in these vulnerable bull trout waters. Compromised waters are defined as those lakes containing lake trout or brook trout. The status of the lake trout invasion and corresponding status of bull trout populations in each lake is variable. These invasions illustrate there are no physical barriers downstream of these lakes to preclude ongoing lake trout movement or future invasions of other species from other waters in the interconnected Flathead Basin. Management actions for compromised lakes are highly variable and in some instances suppression may be an option. However, suppression will require considerable resources because of logistic constraints.