Science Advisory Report  2016/038

Assessment of Arctic Char (Salvelinus alpinus) in the Ulukhaktok area of the Northwest Territories

Summary

• The number of Arctic Char harvested directly from the Kuujjua River was relatively stable at high levels (approx. 3,500 fish) in the 1960s and 1970s.  A decline in stock status was reported by harvesters in the late 1980s and since the mid-1990s, there has been a harvest guideline of 1,000 char for Tatik Lake (Kuujjua River) set by the Olokhaktomiut Hunters and Trappers Committee (OHTC). Currently, the reported harvest is <1,000 fish annually. The total number of Kuujjua River char harvested is unknown due to the uncertainty regarding how many contribute to the mixed-stock coastal harvest.
• Char sampled during the Tatik Lake subsistence winter fishery covered a wide distribution in size (mainly 500–750 mm; 1,000–5,000 g) and age (mainly distributed between 8 and 12 years).  Median length and weight increased from 525 to 630 mm and 1,675 to 3,100 g, respectively, between 2008 and 2012, and have been relatively stable since then at levels similar to those observed in the early 2000s. Median age increased from 8 to 10 years between 2010 and 2012 and has been stable since then. Catch-per-unit-effort (CPUE) has been variable without trend with an increase in the frequency of relatively high values since 2006.
• The summer subsistence and Stage I fishery near Ulukhaktok also harvest a wide range in size (mainly 550–850 mm; 1,000–6,000 g) and age (predominantly distributed between 8 and 13 years). Median length and weight values have been stable at approximately 690 mm and 3,900 g since 2011, with sizes greater than what had been observed between 1993 and 1997. CPUE has also varied without trend although confidence is low for estimates in some of the recent years due to low sample size.
• Data collected between 1995 and 2015 from community harvest surveys and the monitoring program in Tatik Lake were incorporated into a statistical catch-at-age (SCA) model. Preliminary results looked promising, however there were questions raised concerning model inputs and parameterization. Further work is required before results could be used to provide management advice. However, it was noted that the maximum sustainable yield estimate was within range of the current harvest.
• Biological and catch indices indicate that the Kuujjua River population is not experiencing overfishing and the current stock status is healthy. Additionally, local fishers have not reported declines in stock status in recent years. The current level of harvest experienced by the stock appears to be sustainable.

This Science Advisory Report is from the February 15–17, 2016 Assessment of Arctic Char in the Ulukhaktok area of the Northwest Territories. Additional publications from this meeting will be posted on the DFO Science Advisory Schedule as they become available.

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