Science Advisory Report 2018/005

Assessment of White Hake (Urophycis tenuis) in NAFO Subdivision 3P

Summary

• White Hakes in Subdivision 3Ps and Division 3NO constitute a single biological stock, which has been assessed by the Northwest Atlantic Fisheries Organization’s (NAFO) Scientific Council every two years since 2005.
• NAFO-reported landings for Canada were variable over 2000-08 in Subdiv. 3Ps, but remained relatively high: averaging 1,219 t. Since 2009, Canadian average landings have been below 400 t.
• Abundance index for Subdiv. 3Ps from the DFO-NL spring surveys ranged from 4.0 to 15.1 million White Hakes, and biomass index ranged from 2,582 t to 10,294 t over 1996-2016. The average abundance index from 1996-2016 was 7.6 million, and the average biomass index was 5,737 t. In 2017, the abundance index was 7.1 million, and the biomass index was 4,848 t.
• Distributions of White Hake over 2008-17 were consistent with historic data from DFO-NL spring surveys; indicating that White Hakes in Div. 3P were found mostly in the Laurentian, Hermitage, and Halibut Channels.
• Large episodic recruitment of Divs. 3NOPs White Hake was observed in 2000. Recruitment remained at much lower levels since 2001. In 2017, this Divs. 3NOPs index increased, but was still very small in comparison to the last large recruitment peak.
• The relative fishing mortality index for Subdiv. 3Ps has remained below its 1996-2016 average since 2010.
• White Hake biomass and abundance indices for Subdiv. 3Ps increased over the past two years, and recent Canadian average landings below 400 t in this Subdivision did not seem to negatively impact the Div. 3P portion of the Divs. 3NOPs stock.
• Ecosystem signals observed in Subdiv. 3Ps in recent years indicated that structural changes are occurring, and overall ecosystem productivity may be low. Although the direct impacts of these changes on White Hake life stages (i.e., pelagic eggs and larvae, bottom-dwelling juveniles and adults) are unknown, they imply that at least some aspects of White Hake productivity may be affected.
• White Hake in Subdiv. 3Ps is part of the Divs. 3NOPs stock. Difficulties in applying the Limit Reference Point (LRP) concepts to White Hake include its episodic recruitment, and other data limitations. LRP options were not accepted for this species.

This Science Advisory Report is from the November 1, 2017 Subdiv. 3Ps White Hake Stock Assessment. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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