Science Advisory Report 2018/028

Assessment of the whelk fishery in Québec’s inshore waters

Summary

• In 2017, whelk landings in Québec totalled 1,329 t, of which 77% were from the North Shore, 8% from the Gaspé Peninsula–Lower St. Lawrence and 15% from the Îles-de-la-Madeleine. Landings had increased in most fishing areas compared to 2014. The TAC, where applicable, was met only in area 12.
• In 2017, the catch per unit effort (CPUE) was above the reference average (2001–2016 period) in areas 1 and 2, near average in areas 4, 6, 7, 12, 13 and 15 and below average in areas 3, 5 and 8. In the latter three areas, the CPUE measured in 2017 was one of the lowest since 2001.
• Since 2011, average sizes of whelks landed have been fairly stable in all areas. In 2017 landings, the proportion of whelk under the minimum legal size of 70 mm was less than 4%, except in areas 1 (12%), 2 (6%) and 8 (7%).
• The research survey conducted in 2017 in areas 1 and 2 showed that the density of commercial-size whelks was very high in all three sampling sites in comparison to previous years (2005-2015). However, the density of < 70 mm whelks was only fair.
• The average size at which 50% (T₅₀) of Buccinum undatum are sexually mature was re-evaluated in 2015-2017 in most fishing areas. T₅₀ varied between 60 and 94 mm among females depending on the area and between 56 and 86 mm among males.
• Area 10 is not fished, and fishing effort has been sporadic and low in areas 9, 11 and 14. It is therefore impossible to comment on the status of the resource in these areas.
• In the period from 2015 to 2017, stock status indicators (CPUE and size structure) showed a positive trend in areas 1, 2 and 12, were fairly stable in areas 4, 6, 7 and 13 and decreased in areas 3, 5 and 8. In area 15, the CPUE for 2017 showed clear improvement over the very low values observed between 2014 and 2016. However, caution is still recommended in this area, since the CPUE at some sites remained low in 2017 and a severe shell-boring polychaete infestation was observed in a high proportion of commercial-size whelks.
• To promote conservation of this resource, the harvest of immature individuals should be avoided, and at least 50% of females should be allowed to breed once before they are harvested. The legal minimum size should therefore be adjusted to the T₅₀ of females in each area. The legal size could be left at 70 mm in areas 1 and 2. It should be increased to at least 75 mm in area 15 and at least 80 mm in other areas. These changes could be implemented gradually.
• Challenges in relation to latent effort (number of unused traps versus number of authorized traps under management measures) are still encountered in areas 2, 3, 4, 5, 8, 12 and 13, where the number of traps used in 2017 represented only between 20% and 41% of the number of authorized traps. These stocks may not be able to support deployment of the entire potential effort.

This Science Advisory Report is from the February 21, 2018 Assessment of the whelk fishery in the Québec’s inshore waters. 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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