GMSMON-17 WILLISTON RESERVOIR TRIBUTARY - BC Hydro

1.2 Study Area
May 22, 2012
Report No. 1114920016-R-Rev0-2000 6
GMSMON-17 WILLISTON RESERVOIR TRIBUTARY HABITAT
REVIEW
The 2011 sampling program focused on the lower reaches of each tributary where each creek flows into
Williston Reservoir and upstream approximately 1.1 km, typically to where the nearest Forest Service Road
crossed each creek. A summary map showing the location of each site (Map 1) and sampling plots (Maps 2 to 5)
are provided in Appendix A and photos of the tributary mouths are shown in Appendix B.
Descriptions of the Site’s biological environment are based on the Ecoregion system and Biogeoclimatic (BGC)
Ecosystem Classification (BEC) system. The Ecoregion classification system provides a systematic review of
the small-scale ecological relationships in the province; the Site is located in the Humid Temperate Ecodomain,
Humid Continental Highlands Ecodivision, Sub-boreal Interior Ecoprovince, Omineca Mountains Ecoregion and
Parsnip Trench Ecosection. The BEC system delineates the province into BGC zones based on topographic and
climatic conditions that are reflected by the presence of specific plant and animal communities. Based on
mapping provided on the iMap BC (Government of BC 2009), the Site occurs within the Williston Sub-Boreal
Spruce moist cool biogeoclimatic unit (SBSmk2).
2.0 METHODS
2.1 Fish surveys
2.1.1 Spawner surveys
Stream walks were conducted for each study creek to enumerate the number of spawners and redds. One
person walked up each stream bank starting at the outlet. All habitat types were assessed for fish presence and
for evidence of spawning (i.e., cleared gravel patches). Effort was dependant on ease of access and habitat
suitability. For example, where stream banks were difficult to traverse, surveyors would concentrate their effort to
point features such as riffles and gravel substrate areas. Stream walks were conducted to target potential Arctic
Grayling spawning at all four study creeks during the first field site visit (9 to 18 May, 2011) and on Six Mile and
Lamonti creeks during the second site visit (6 to 8 June, 2011). The second visit was timed to target potential
Rainbow Trout spawning. High flow conditions in the study streams during the second visit prevented stream
walk surveys on Ole and Factor Ross creeks.
The locations of suitable spawning substrates observed during the surveys were recorded using a GPS.
Observations were made near the mouths of the study creeks to document any potential barriers to fish
movement (i.e., debris jams or perched mouths).
In addition to visual surveys for redds and spawners during stream walks, a number of other techniques were
attempted to assess the suitability of these methods for detecting spawning activity in the study creeks. In
reaches suitable for spawning, fly-fishing was used to attempt to capture spawning adults and kick-net sampling
was used to sample gravels for eggs. Fly fishing was conducted in Lamonti and Six Mile creeks during the Arctic
Grayling survey. Effort was concentrated on pools of adequate size that they might contain adult fish. A total of
two to five minutes were spent angling with dry flies in each selected pool. Some snorkelling was also conducted
to look for spawners and redds but efforts were limited because of high flow conditions. Only Six Mile Creek
contained adequate habitat in which to conduct snorkel surveys during early spring but Lamonti Creek was also
sampled. An average of five minutes were spent surveying each pool in Six Mile Creek while less time (average
of two minutes) was spent in each Lamonti Creek pool due to the small pool sizes. Given the low success rate