Clayton Falls Project Water Use Plan Aquatic - BC Hydro

Clayton Falls WUP Aquatic Productivity Monitoring Program – Year 1, 2005
from the shore-based unit. These proven methods facilitated fast, safe and efficient capture of
fish species from cobble-boulder interstitial spaces.
Fish were captured by the anode pole operator or two support samplers using 19 cm diameter
nets. This diameter was considered large enough to capture smolt-sized fish of 17 cm (Ptolemy
et al. 2006). The anode operator periodically over turned rocks to hand-recover fish that had
drifted into difficult interstitial spaces.
Following methods described by Ptolemy et al. (2006), electrofishing at each site was initiated
at the downstream net, and consisted of a thorough habitat search with the electrofisher anode
in an upstream direction, followed by a systematic sweep back towards the downstream net. To
avoid chasing larger juveniles from the site electrofishing proceeded from the fast water forming
the offshore boundary towards the shore (Photo 4). Each “catch” (c1, c2, c3, etc.) effort
involved multiple passes and the same search pattern was replicated in each catch effort. This
type of three-sided sample method was described by Ptolemy et al. (2006) as potentially
offsetting measurement error caused by exceptions to total site enclosure through greater
sampling efficiency afforded by shore-based electrofishing.
2.2.1 Fish Sampling
Salmonids captured during electrofishing were anaesthetized, identified as to species,
measured to the nearest mm (fork length, FL), weighed, and released alive back into the site
following the final completion of sampling. A portion of the coho parr captured from Reach 2
were also sampled for scales, which were taken from the sides of fish approximately 2-4 scale
rows above the lateral line and between the back of the dorsal fin and the insertion of the anal
fin. Scale samples were collected and retained by Ministry of Environment personnel assisting
with the project (R. Ptolemy). Numbers of non-salmonid fish were recorded to Genus (e.g.,
Cottus sp.). with no other data collected from those specimens.
2.3 Benthic invertebrate Collection
Benthic invertebrates were to be collected over a six to ten week period representative of
predicted winter low flow conditions (e.g., ~0.05 m 3 /s). Twelve benthic invertebrate baskets,
supplied by BC Hydro, were filled with clean cobble and placed in the stream substrate of
Reaches 2 and 3 to monitor benthic invertebrate colonization (six baskets at Reach 2 and six at
Reach 3).
In 2005 difficulties were experienced in placing these sample baskets in the stream channel. It
was noted that low flow conditions were not observed to the extent anticipated in fall-winter of
2005. Although accurate discharge data were not available for the sample periods (described in
Results, Section 3.0 below), it appeared discharge typically well exceed 0.05 m 3 /s and benthic
invertebrate sample baskets could not effectively be placed in the stream channel in a
representative location to accurately collect information or data related to expected low flow
periods.
In addition to placement discharge/timing issues, it was further determined baskets were
ultimately of inappropriate shape and dimension for effective colonization (baskets measured
30 cm x 30 cm x 10 cm), limiting the size and amount of substrate material that could effectively
be placed in the sample basket, as well as depth they could effectively be placed within the
predominantly large boulder natural stream substrate. Subsequently, benthic invertebrate
Kynoch Resources
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