Babine River Counting Fence

Photo: 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.