Falls River Project Water Use Plan Falls River Fish ... - BC Hydro

Falls River WUP Monitoring 2008/2009
1.2 Periodicity Review and Incubation Assessment
1.2.1 Periodicity Review
A periodicity review was conducted in 2007; a component of a report written for BC Hydro as part
of a 5 year Water Use Plan (WUP) monitoring program (CGL and Metlakatla Fisheries, 2007),
focusing on historic and anecdotal fish presence, migration and spawning timing information for
steelhead, Chinook, chum, coho and pink salmon for the Ecstall and Falls rivers.
Results of the review that focused on Chinook salmon are summarized below.
Migration into the Ecstall River occurs in late July and August. Spawning occurs in early September
(FISS). Migration into the Falls River system occurs in late August; spawning begins late in August
and peaks in early September and may continue through October (FISS). Chinook spawners and
redds have been noted in the Falls River tailpond in late August and early September by a variety of
sources (Redenbach 1981; Hickey 1981; Bullock, R. pers. comm.; William Beynon, pers. comm.).
Chinook presence and spawning has been recorded in the Falls River tailpond at the base of the falls,
below the powerhouse and in gravel areas downstream between 1955 and 2003. Observations
typically occur between August 12 th and September 22 nd ; however dates are not provided for some
years (DFO, BC 16’s Summary Sheet).
BC Hydro staff indicated that a detailed fisheries assessment, focused on potential habitat
rehabilitation at the Falls River facility, was completed in 1980 (B. Mossop, pers. comm. - 2007 re:
Redenbach 1981). During the Redenbach (1981) study, bright Chinook were angled and observed
in the Falls River between August 20 th and 30 th , 1980. In the following year, from August 7 th to
September 23, 1981, a total of 15 possible salmon redds were noted in the tailpond, including 2
confirmed Chinook spawning pairs (Hickey 1981).
Between April and October, 2007 and during the same period in 2008, a total of 14 snorkel and
angling surveys were conducted for BC Hydro as part of a 5 year Water Use Plan (WUP) monitoring
program (CGL and Metlakatla Fisheries 2007; CGL and Metlakatla Fisheries 2008). No adult
steelhead or salmon were viewed in the tailpond during these surveys.
For the purposes of this study, we used an estimated spawning timing for Chinook salmon from mid
August until late September to help plan timing of field work.
1.2.2 Incubation Assessment
In 2003/2004 Fisheries and Oceans Canada (DFO) and Northcoast Environment conducted a
Chinook incubation study in the Falls River tailpond, in follow-up to a feasibility study conducted in
2002 (Miller et al., 2002). During this study, one pair of Chinook spawners and 7 redds (assumed
to be from Chinook and pink salmon) were observed in the Falls River tailpond in early September,
2003 (Figure 4). The study team noted that redds located in the tailpond were flattened by spilling
outflows, and were no longer visible the next day. For the incubation component of the study, 22
Jordan Scotty cassettes with 200 Chinook (fertilized on site) eggs per cassette were buried at 4 sites
(Figure 4) on September 9th, 2003. Table 1 displays the percent survival rate to eyed, and hatch
stages found on survey dates conducted on January 13th and March 3 rd of 2004.
Cambria Gordon and Metlakata Fisheries 4