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Pacific Region North Coast
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Babine River Counting Fence
Babine
River Fence Counts 1990 - 2011
The Babine River Counting Fence
The Babine River salmon counting fence is
located one kilometre downstream of Nilkitkwa Lake, 360 km from the commercial
fishing boundary at the mouth of the Skeena River. The counting fence was
established in 1946 and is used to provide an accurate escapement count of
sockeye and other species of salmon entering Babine Lake, where up to 90% of the Skeena River sockeye are produced in any given year.
The counting fence is
normally installed in early July depending on water levels in the Babine River. Installing the fence entails
positioning 66, 4 by 7-foot aluminium panels in
their respective places along the 330-foot frame that spans the entire
width of the Babine River. Seven holding traps,
approximately 6 feet wide by 8.5 feet long are spaced across the river on
the upstream side of the frame. After all the panels are in place, each of
the seven traps is made operational by positioning sliding doors and
counting chutes.
All species of salmonids are present in the Babine River with sockeye being the most
numerous. Large numbers of pink salmon are also present and spawn directly
above the counting fence. When post spawning mortalities occur, the fence
soon becomes littered with their carcasses, which are subsequently pitched
over the fence. The fence is opened to allow fish through from 0600h to
2200h daily and counting between these times is performed in a series of
two hour shifts by two, three, and sometimes, depending on the strength of
that day’s run, four persons. At the end of the salmon migration, the
aluminium panels are removed and the camp is
closed down.
Sampling
Every day of the
migration 25 sockeye are randomly removed from the traps for the purpose of
sampling. The procedure consists of sampling for sex, nose fork and hypural lengths and general age, size and sex make-up
of that year’s migration, therefore enabling potential egg deposition
to be estimated. Chinook salmon are sampled after spawning as they are
removed from the fence during that day’s deadpitch.
All chinook, with the
scarce exception of those that are badly decomposed are sampled for scales,
sex, nose fork and hypural lengths, origin
(hatchery or wild stock by adipose fin) and in the case of females, egg
retention. Pink salmon are sampled for sex and nose fork length. As is the
case with chinook, pink salmon are easily
recovered from the fence during that day’s deadpitch
and it is at this time that the 100 daily samples are obtained. An effort
is made to stop and sample each coho with a
missing adipose fin for scales, length and sex.
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