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INSTITUTE FOR MARINE AND ANTARCTIC STUDIES

INSTITUTE FOR MARINE AND ANTARCTIC STUDIES. www.imas.utas.edu.au. 2012 May/June BSCZSF Surveys. IMAS - in collaboration with the Tasmanian State Government. 234* sample tows conducted by 2 vessels in the BSCZSF in May/June 2012.

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INSTITUTE FOR MARINE AND ANTARCTIC STUDIES

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  1. INSTITUTE FOR MARINE AND ANTARCTIC STUDIES www.imas.utas.edu.au 2012 May/June BSCZSF Surveys IMAS - in collaboration with the Tasmanian State Government

  2. 234* sample tows conducted by 2 vessels in the BSCZSF in May/June 2012. • Three main areas: 1 (Western Protected Area), 2 (2009 open area and viable area 10), 3 (Southern Protected Area), Area 4, Area 5* (not shown) and Area 6 (Lady Miriam – Edge of 2011 Area)

  3. Area 1 (Western Protected Area): • 48 shots (NS only) • Average density 14 kg/1000 m2 • Ave New dead shell per shot 6%

  4. Biomass Estimate (33% efficiency)

  5. Area 1 (Western Protected Area)

  6. Size Frequency (2385 scallops NS only)

  7. November 2011 Size Frequency (965 scallops)

  8. Area 2 (2009 Open Area and Viable Area 10): • 40 shots (Anne B only) • Average density 10 kg/1000 m2 • Ave new dead shell per shot 16%

  9. Biomass Estimate (33% efficiency)

  10. Size Frequency (1463scallops AB only)

  11. November 2011 Size Frequency (1053 scallops)

  12. Area 3 (Southern Protected Area): • 48 shots • Average density 9 kg/1000 m2 • Ave New dead shell per shot 23%

  13. Biomass Estimate (33% efficiency)

  14. Size Frequency (761 scallops)

  15. November 2011 Size Frequency (694 scallops)

  16. Area 4: Size Frequency (386 scallops) • Average density • 5 kg/1000 m2

  17. Area 4: November 2011 Size Frequency (137 scallops) • Average density 5.4 kg/1000 m2

  18. Summary • Only Area 4 was below the discard rate, but had low densities. • Area 1 scallops ranged from 69 to 123 mm and the discard rate was 25.1%. A large number of the undersized scallops were in the 80-89 mm size classes. • Area 1 had an average scallop density of 14 kg per 1000m2. This equates to approximately 0.15 scallops per m2 of the benthos. • Area 3 appears to have declined since November 2011.

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