We propose to install two SONAR units on the right and left banks of the Quesnel River at a proven sockeye enumeration SONAR site in order to accurately and precisely enumerate Quesnel system Interior Fraser Coho (IFC). The Coho SONAR enumeration program will run for three years, from 2018 to 2020, using SONAR and related equipment provided in-kind by the UFFCA and DFO. Overlap in timing between sockeye and IFC will allow the continuation of existing sockeye SONAR operations for Interior Fraser Coho enumeration.
Currently, escapements to the Quesnel system are estimated using a single enumeration fence at McKinley Creek, as well as boat, foot and aerial counting methods for Quesnel Lake and Horsefly River tributaries. Visual counting of Coho is difficult due to extreme weather events, seasonal limitations (late fall, early winter), extended and multimodal migrations, the defensive/cryptic nature of the animal and its choice of small, complex tributaries for spawning.
Due to potential shortfalls (funding/weather/accuracy) in the aerial enumeration program, the key objective of this research is to develop an index between a SONAR count on the Quesnel and the McKinley enumeration fence count in order to establish a system-wide escapement estimate (relationship) based on the McKinley fence.