Bull Trout Population Status Assessment in the Upper Oldman River Watershed, 2008 - Phase 2 Findings


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The Alberta Conservation Association (ACA) is conducting a bull trout population status assessment in the Upper Oldman River (UOM) watershed. The study focuses on intercepting migratory adult bull trout with fish traps stationed in spawning streams throughout the UOM drainage. Redd surveys are also conducted at each spawning stream to account for spawning bull trout that fail to be captured.

Identifiable passive transponder tags are applied to each captured adult bull trout that will, in the event of a recapture, permit a fish’s migratory movements to be tracked. Tracking migratory fish movements will provide ACA and fisheries managers with a greater understanding of the migratory patterns and behaviors expressed by the UOM bull trout.

During the preliminary phase of the study (2007), a fish trap was stationed in Hidden Creek, a historic bull trout spawning stream, to intercept migratory adult bull trout. To understand the timing of bull trout spawning movements, a uni-directional fish trap was stationed in the creek to intercept pre and post spawning fish. The objectives of the preliminary phase were to determine the significance of Hidden Creek as a bull trout spawning stream, and to identify the post spawning period when migratory bull trout complete their spawn and migrate out of the stream. Redd surveys were not conducted during the preliminary phase of the study.

The following year, 2008, four directional fish traps, targeting post spawning migratory bull trout were stationed in four spawning streams: Hidden Creek, Racehorse Creek, Dutch Creek, and Livingstone River (Figure 1). Redd surveys were completed at each of these bull trout spawning streams to identify primary spawning areas so they can be resurveyed and analyzed over consecutive years.

A complete redd survey census was assessed throughout Hidden Creek to enumerate all bull trout redds and to key in on all primary redd areas (Figure 2). The census effort was initiated to collect baseline data prior to the timber harvesting in the Hidden Creek drainage proposed for the summer of 2009.

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