Stock Assessment

Swim Enumeration

NVISEA employs certified swift water technicians, trained in species identification and river safety. These personnel are contracted to conduct snorkel swim enumerations for the Department of Fisheries and Oceans and for the Ministry of Environment. NVISEA provides their technicians with the necessary equipment to safely conduct these surveys, including dry suits, snorkels and masks, flotation vests, satellite telephones and four wheel drive transportation. Assessments for fall spawner salmon species are conducted on the Marble River, Artlish River, Kaouk River, Tahsish River, and the Colonial/Cayeghle Rivers. Winter steelhead index swims are conducted on the Cluxewe River. NVISEA has also been involved with swims searching for Atlantic salmon adults and juveniles in a number of North Island and central mainland rivers.

Electronic Counters

NVISEA has partnered with DFO and the Kwakiutl First Nation to use an advanced in-stream counting device known as DIDSON (Dual Frequency Identification Sonar). This technology makes it possible to assess a unique May run of Quatse River sockeye salmon, which would otherwise be difficult due to the tannin colour of the Quatse River.

DIDSON counter in the Quatse River

Sonar image of salmon

NVISEA has also partnered with DFO and Ministry of Environment in the operation of the Keogh River Resistivity Counter and Enumeration Fence. The Keogh River is DFO's Area 12 index stream and is one of B.C.'s longest data sets on adult returns, smolt out migrations and ocean survival.

Juvenile Enumeration

NVISEA is active in a number of juvenile enumeration projects.

NVISEA partners with the Keogh River Enumeration Fence to assess smolt outmigration population and timing. The fence is operated yearly, from April to mid-June.

NVISEA also partners with the Friends of the Marble River Society for the operation of the Marble River rotary screw trap and the Sara Lake outlet fence.

For our O'Connor Lake net pen site, NVISEA operates a fence on the lake's outlet stream, serving a dual purpose of enumerating the O'Connor Lake contribution to Keogh River outmigrants and acting as a safeguard capturing hatchery-clipped escapees.

NVISEA also conducts presence/absence surveys, species identification and distribution surveys and fry salvage/removal projects. NVISEA utilizes electrofishers, minnow traps and juvenile seine and isolation nets to perform these tasks. 

Environmental Monitoring

NVISEA has the technical expertise and equipment to perform a wide variety of environmental monitoring projects. Past projects have involved monitoring bridge re-decking, road deactivation, culvert removal and replacement and fish habitat construction.


Please contact NVISEA for our current professional rates and services