Science Advisory Report  2011/010

Assessment of Northern Shrimp (Pandalus borealis) and Striped Shrimp (Pandalus montagui) in Western and Eastern assessment zones (SFA 2 and 3)

Summary

• The thermal regime has been warming over the past five years. Effects of a warm regime on shrimp distribution and behaviour are unknown. However any effect may be greater on Pandalus montagui than P. borealis because of its preference for cooler waters.
• Two new assessment zones for the assessment of the Pandalus resources in the Arctic were adopted. As no new information was available for the Western Assessment Zone, no new advice was formulated. The advice from the 2010 assessment corresponding to this zone was carried forward.
• Pandalus borealis and Pandalus montagui were assessed in the new Eastern Assessment Zone.
• Since the 2010 assessment, one Northern Shrimp Research Foundation (NSRF)-DFO survey of SFA 2 Exploratory (EX) and Resolution Island Survey Area (RISA) provided the fishery-independent data for this assessment.
• Survey biomass, fishery data and fishery exploitation rate indices are used to assess the resources.

Eastern Assessment Zone – P. borealis

• The catch varied without trend at about 6,000 t since 1996.
• CPUE shows a strong upward trend in the time series but is believed to reflect changes in fishing patterns not resource status.
• Survey data are available for the period of 2006–2010, however the first two years are not considered to be comparable with the rest of series.
• Fishable biomass and female spawning stock biomass indices have not changed significantly over the period 2008-2010. The fishable biomass index was about 42,500 t from 2008–2010 and the female spawning stock biomass index was about 24,000 t from 2008–2010.
• Recruitment is uncertain.
• The observed exploitation rate index has varied without trend since 2007/08 around a mean of 9%.
• Under the Integrated Fisheries Management Plan Precautionary Approach Framework, the female spawning stock biomass has been in the Healthy Zone for the past four years but only the last three years are considered informative. The exploitation rate over this period has averaged 9% which is below the base target exploitation rate of 15% for the Healthy Zone.

Eastern Assessment Zone – P. montagui

• The catch declined steadily from about 4,000 t in 1999 to about 500 t in 2009/10. This is thought to be a consequence of changes in fishing patterns, market conditions and alternative fishing opportunities after 1999.
• Survey data are available for the period of 2006–2010 however the first two years are not considered to be comparable with the rest of series.
• Fishable biomass and female spawning stock biomass indices decreased in 2010. This may be caused by a distributional shift away from warmer water. The fishable biomass index was about 15,000 t in 2008–2009 and 7,400 t in 2010. The female spawning stock biomass index was 11,000 t in 2008 and 5,800 t in 2010.
• Recruitment is uncertain.
• The observed exploitation rate index has varied without trend since 2007/08 around a mean of 5%.
• The potential exploitation rate index based on total TAC has varied without trend since 2007/08 around a mean of 56%.
• Female spawning stock biomass has declined into the Cautious Zone of the Integrated Fisheries Management Plan Precautionary Approach Framework and is slightly below the Upper Stock Reference.

Western Assessment Zone^{Footnote 1} – P. borealis

• Resource status is based on two survey years, 2007 and 2009 using the Cosmos trawl.
• Fishable biomass index for the two years was 14,600 t (2007) and 15,500 t (2009).
• Female spawning stock biomass index was 3,200 t (2007) and 3,800 t (2009).
• Recruitment is uncertain.
• Prospects are uncertain due to limited data.

Western Assessment Zone^{Footnote 1} – P. montagui

• Resource status is based on two survey years, 2007 and 2009 using the Cosmos trawl.
• Fishable biomass index was 48,400 t (2007) and 46,700 t (2009).
• Female spawning stock biomass index was 16,700 t (2007) and 18,000 t (2009).
• Recruitment is uncertain.
• Prospects are uncertain due to limited data.

This Science Advisory Report has resulted from a Fisheries and Oceans Canada, Canadian Science Advisory Secretariat zonal advisory process held 15-25 February 2011 on the assessment of northern and striped shrimp in Shrimp Fishing Areas (SFAs) 2-6. Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

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