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

Falls River WUP Monitoring 2008/2009
designed to hold 200 eggs, there is concern that the availability of Chinook eggs from local
Hatchery facilities may be limited, based on discussions with Hatchery Managers. The statistical
analyses of the study results will be more powerful if more incubators with fewer eggs (i.e. 8
incubators with 100 eggs) as opposed to fewer incubators with more eggs (i.e. 4 incubators with
200 eggs) are used, to deal with the variability in survival and differential survival rates between sites.
Eight incubation cassettes will be buried at each incubation site for a total of 16 cassettes (1600
eggs) for the study group. The cassettes will be buried in an artificial redd excavated in the substrate,
in groups of two placed 30-40 cm apart, to a depth of ~25 cm, such that the top of each cassette
will be approximately 10-15 cm below the surface of the gravel (Figure 14). Each cassette will be
secured by a 50 cm length of ¼ inch polypropylene rope to a 30 cm length of rebar, driven into the
substrate upstream of the cassettes. Cassettes will be flagged with an ID number so they can be
easily located.
A control group of eyed eggs from the same donating adults will remain separate at the Hatchery
facility. The primary purpose of this group will be to demonstrate that there were no fertilization or
survival issues with the batch of eggs used in the study when incubated in an ideal environment. The
treatment of this group of “control” eggs in the same manner as the study group will require that
eyed eggs be placed in Jordan-Scotty incubation cassettes and incubated to the fry/emergence stage
in upwelling incubators (Atkins cells) or other upwelling bulk-type incubator at the designated
facility. If this can not be accommodated due to restricted facility operations, space or availability of
eggs, then the “control group” should be handled using standard hatchery practices of the facility
such that the eyed eggs from which the study group was taken can be maintained separate from
other groups at the hatchery, and survival tracked to the hatch and fry/emergence stages.
Assessment of incubation success will be checked during two stages: at the hatching stage (~520
ATUs), and at the fry/emergence stage (~920 ATUs). Based on water temperatures and ATUs from
2008/2009 this would equate to survey times in early November (hatch) and early May
(emergence). The incubators to be used in this study (Jordan-Scotty incubators) have blocked escape
holes which permits more accurate assessment to the fry stage with no loss of embryos. The
developmental stage of the incubating eggs will be monitored using temperature data collected from
a buried Tidbit temperature logger at the Falls River site to calculate ATUs and schedule the egg
assessment date at the hatch and fry stages. Hatch and emergence site visits will be adjusted from
the 2008/2009 temperature dataset if required (i.e., if water temperatures are warmer or colder at
the time of incubations cassette installation in September).
For each developmental stage inspection, four cassettes from each site will be removed and
assessed. The contents of the incubators will be emptied into a shallow basin and the number of
dead and live eggs/alevins and fry enumerated. The embryos (live and dead) will be handled as per
conditions in the Transplant Permit. Cassettes removed at the hatch stage will not be replaced in the
gravel after assessment due to the amount of disturbance that would be required to excavate and
replant the incubators. This disturbance could adversely affect the embryos in the cassette, as well as
alter the intragravel conditions of flow, permeability and dissolved oxygen delivery within the ‘egg
pocket’ or the surrounding environment of other nearby cassettes, thereby skewing results for the
final stage of development.
Cambria Gordon and Metlakata Fisheries 28