Science Advisory Report  2013/031

Assessment of Northern Shrimp (Pandalus borealis) and Striped Shrimp (Pandalus montagui) in the eastern and western assessment zones (Shrimp Fishing Areas 2 and 3)

Summary

• The thermal regime in the Eastern Assessment Zone has moderated from the higher temperatures of 2010 and 2011 down to the levels seen during the first four years of the survey. There are no new survey data for the Western Assessment Zone and the advice from the 2012 update corresponding to these data was carried forward. The assessment includes the fishery data since the 2012 update.
• Since the 2012 update, one Northern Shrimp Research Foundation – Fisheries and Oceans Canada survey of Shrimp Fishing Area 2 Exploratory and Resolution Island Survey Area provided the fishery-independent data for this assessment.
• Survey biomass, fishery data, and fishery exploitation rate indices are used to assess Pandalus borealis and Pandalus montagui.

Eastern Assessment Zone – Pandalus borealis

• Total catches (directed and by-catch) of Pandalus borealis varied without trend at about 6,000 t for 1997 through 2009/10. Increases in catch in the 2010/11 and 2011/12 fishing season mainly came from increased effort and catch in the Shrimp Fishing Area 2 east of 63°W. Catch statistics in 2012/13 are not fully available but it is unlikely the Total Allowable Catch will be taken.
• The fishable biomass index ranged from 51,000 – 79,000 t from 2008 – 2012 averaging about 68,000 t. Female spawning stock biomass index ranged from 28,000 – 48,000 t averaging about 40,000 t for the same period. The 2012 fishable biomass index was 60,000 t and female spawning stock biomass index was 41,000 t.
• Recruitment prospects are uncertain.
• The observed exploitation rate index has varied without trend since 2007/08 around a mean of 9%. The catch was well below the Total Allowable Catch. Based on the 2012/13 Total Allowable Catch of 9,150 t the potential exploitation rate would be 15%.
• Under the Integrated Fisheries Management Plan Precautionary Approach Framework, the female spawning stock biomass index for the Eastern Assessment Zone remains within the Healthy Zone for 2012/13.

Eastern Assessment Zone – Pandalus montagui

• The catch declined steadily from about 4,000 t in 1999 to about 135 t in 2011/12, then increased to 656 t in 2012/13. The decline is thought to be a consequence of changes in fishing patterns, market conditions, and alternative fishing opportunities. The increase in 2012/13 is mainly from renewed fishing effort in the Nunavik Marine Region.
• The fishable biomass index ranged from 7,400 – 29,000 t from 2008 – 2012 averaging about 15,000 t. Female spawning stock biomass index ranged from 5,800 – 24,000 t averaging about 10,000 t for the same period. The 2012 fishable biomass index was 29,000 t and female spawning stock biomass index was 24,000 t. It is not possible that the biomass increase resulted from local growth.
• Recruitment prospects are uncertain.
• The observed exploitation rate index has varied without trend from 2007/08 through 2011/12 around a mean of 6%. The exploitation rate for 2012/13 is uncertain because of concerns raised about the biomass estimate.
• The female spawning stock biomass index in the Eastern Assessment Zone had been declining into the Cautious Zone and approaching the Limit Reference Point in 2011/12. Although the sharp increase in the female spawning stock biomass index in 2012 has moved it back into the Healthy Zone well above the Upper Stock Reference, concerns about the biomass estimate suggest caution.

Western Assessment Zone^{Footnote 1} Pandalus borealis

• Observer records reported catches of 60 t of Pandalus borealis in 2010/11, 0 t in 2011/12, and 6 t in 2012/13.
• In 2011, the Pandalus borealis fishable biomass index was 19,700 t and female spawning stock biomass index was 6,400 t similar to previous surveys.
• Reference points were developed for the Precautionary Approach Framework. Upper Stock Reference (3,400 t) was defined as 80% and the Limit Reference Point (1,300 t) was defined as 30% of the geometric mean of the spawning stock biomass for the three surveys. These will be re-evaluated when additional data become available.
• The female spawning stock biomass index for the Western Assessment Zone places the resource in the Healthy Zone of the Precautionary Approach Framework. The 1,500 t Total Allowable Catch for the Western Assessment Zone for the 2013/14 fishing season will result in a potential exploitation rate of 8% if the biomass observed in the 2011 survey is unchanged in 2013.

Western Assessment Zone^{Footnote 1} – Pandalus montagui

• Observer records reported catches of 300 t of Pandalus montagui in 2010/11, 840 t in 2011/12, and 1,300 t in 2012/13.
• In 2011, the Pandalus montagui fishable biomass index was 71,500 t and female spawning stock biomass index was 32,500 t similar to previous surveys.
• Reference points were developed for the Precautionary Approach framework. Upper Stock Reference (18,000 t) was defined as 80% and the Limit Reference Point (6,700 t) was defined as 30% of the geometric mean of the spawning stock biomass for the three surveys. These will be re-evaluated when additional data become available.
• The female spawning stock biomass index for the Western Assessment Zone places the resource in the Healthy Zone of the Precautionary Approach Framework. The 5,000 t Total Allowable Catch for the Western Assessment Zone for the 2013/14 fishing season will result in a potential exploitation rate of 7% if the biomass observed in the 2011 survey is unchanged in 2013.

This Science Advisory Report is from the February 18-20, 2013 2013 Assessment of Northern and Striped Shrimp. 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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