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Keri L. Stepanek Maine Department of Marine Resources January 8, 2014

Results from the Maine-New Hampshire Inshore Trawl Survey: Potential Prey and Predators of Atlantic Salmon. Keri L. Stepanek Maine Department of Marine Resources January 8, 2014. Survey Goals.

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Keri L. Stepanek Maine Department of Marine Resources January 8, 2014

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  1. Results from the Maine-New Hampshire Inshore Trawl Survey: Potential Prey and Predators of Atlantic Salmon Keri L. Stepanek Maine Department of Marine Resources January 8, 2014

  2. Survey Goals • To provide a long-term fisheries-independent data base on the distribution and relative abundance of marine resources in the near shore Gulf of Maine. • To gather biological information (age at length, sexual maturity, food habits, and habitat use). • To consistently provide data that is valued by both industry members and scientists • To foster collaborative research between scientists and the fishing industry

  3. Survey Operations • F/V Robert Michael – Downeast 54’ commercial fishing vessel • Flagg Research Trawl – modified shrimp net, 2” mesh, 1” liner in cod end • 20 minute straight tows, 2.5 knots (~0.8 nm) • Stratified random design (95 random sites, 20 fixed stations) – target of 115 tows per survey • Biannual surveys, spring and fall

  4. Data • Indices of Abundance • Distribution Maps • Catch at Length • Catch at Age (Otoliths Backlogged) • Maturity • Sex Ratios • Food Habits • Temperature and Salinity Profiles

  5. Fall 2012 Sept. 24 – Oct. 26 99 sites warmest fall since survey inception (11.30 C) Spring 2013 May 6 – June 6 113 sites

  6. Occurrence of Prey Species • Atlantic herring • Alewife • Blueback herring • Rainbow smelt • Silver hake • Butterfish • Pandalid shrimp

  7. Atlantic Herring • Spring average total number ~140,000 • Range of 3 to 38 cm total central length • Mean length 12.9 cm

  8. Spring 2013 Atlantic Herring Number Per Tow

  9. Spring 2013 Atlantic Herring Number Per Tow

  10. Alewife • Spring average total number ~13,900 • Range of 5 to 30 cm total central length • Mean length 11.2 cm

  11. Spring 2013 Alewife Number Per Tow

  12. Spring 2013 Alewife Number Per Tow

  13. Blueback Herring • Spring average total number ~1,700 • Range of 8 to 30 cm total central length • Mean length 12.4 cm

  14. Spring 2013 Blueback Herring Number Per Tow

  15. Spring 2013 Blueback Herring Number Per Tow

  16. Rainbow Smelt • Spring average total number ~960 • Range of 4 to 25 cm total central length • Mean length 13.6 cm

  17. Spring 2013 Rainbow Smelt Number Per Tow

  18. Spring 2013 Rainbow Smelt Number Per Tow

  19. Silver Hake • Spring average total number ~30,500 • Range of 4 to 46 cm total central length • Mean length 15.8

  20. Spring 2013 Silver Hake Number Per Tow

  21. Spring 2013 Silver Hake Number Per Tow

  22. Spring 2013 Shrimp Number Per Tow

  23. Spring 2013 Butterfish Number Per Tow

  24. Predators • Atlantic cod • Monkfish • White hake • Red hake • Silver hake • Sea Raven

  25. Atlantic Cod

  26. Monkfish

  27. White Hake

  28. Red Hake

  29. Silver Hake

  30. Sea Raven

  31. Summary • Large abundance of forage species near shore in spring months • Overall presence of large predators is sparse and further away from the shallows

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