Fisheries monitoring and biological data of the Yellowknife River Cisco (Coregonus artedi) population, 1999–2020

PURPOSE:

"Biological, relative abundance, and environmental data have been collected from the Yellowknife River Cisco population that can be used to inform fisheries management decision-making. Under the conditions of a commercial licence issued under the New Emerging Fisheries Policy, licence holders are required to record catch and biological information to support the assessment of the feasibility and sustainability of the fishery over time, and potential advancement in the stages of a developing fishery. In addition to the information collected from the commercial harvest (fishery-dependent), a fishery-independent sampling and snorkel survey program was conducted with the objective of collecting additional biological, observational, and environmental data during the fall spawning run.

The objective of this report is to compile available data from fishery-dependent and fishery-independent sampling of adfluvial Yellowknife River Cisco during fall, 1998-2020*, specifically by:

• Summarizing commercial fishery quotas and reported harvest;

• Characterizing population demographics and examining for trends over time;

• Summarizing metrics of relative abundance (i.e., catch-per-unit-effort data and snorkel survey observations) and examining for trends over time; and

• Determining if there were any associations between relative abundance of Cisco and river discharge and temperature.

*A commercial harvest occurred in 1998, although no biological or catch-effort records were located. In addition, in response to concerns about the status of the population, the fishery was put on hold 2006–2009 to allow for a population assessment (no data during that time).

DESCRIPTION:

Cisco (Coregonus artedi) from the Yellowknife River, Northwest Territories, are an important fishery resource for nearby communities. Biological, catch-effort, and environmental data were collected from the Yellowknife River (Tartan Rapids and Bluefish areas) during their fall spawning run from Great Slave Lake. Data from the commercial harvest (fishery-dependent; 1998–2020) and supplementary monitoring (fishery-independent; 2013–2020) of these adfluvial Cisco were compiled to summarize commercial fishery quotas and reported harvest, characterize population demographics and catch-effort over time, and assess potential associations between relative abundance and seasonal river characteristics. A single commercial fishing licence for Cisco was issued on an annual basis each fall for 1,000 kg from 1998–2002, 2,000 kg from 2004–2005, 1,000 kg from 2010–2018, and 1,500 kg from 2019–2020. Cisco ranged from 102–239 mm fork length, 10.0–139.6 g round weight, and 1 and 9 years of age, with the majority of fish (>99%) being sexually mature. The demographics (length, weight, age) of the spawning population collected from the commercial fishery remained relatively stable between 1999 and 2020. Catch-effort of the commercial fishery varied widely among years without trend, although this was not standardized to the number of individuals/nets used to capture the fish. The biological, catch-effort, and environmental data collected from the Yellowknife River spawning population of Cisco serve as a benchmark for their ongoing assessment and management.