C S A S S C C S Canadian Science Advisory Secretariat Secrétariat canadien de consultation scientifique Research Document 2009/008 Document de recherche 2009/008 An Ecological and Oceanographical Évaluation écologique et Assessment of the Alternate Ballast océanographique de la zone Water Exchange Zone in the Hudson alternative pour l’échange des eaux Strait Region de ballast de la région du détroit d'Hudson D.B. Stewart and K.L. Howland Fisheries and Oceans Canada Central and Arctic Region, Freshwater Institute 501 University Crescent Winnipeg, Manitoba R3T 2N6 This series documents the scientific basis for the La présente série documente les fondements evaluation of aquatic resources and ecosystems scientifiques des évaluations des ressources et in Canada. As such, it addresses the issues of des écosystèmes aquatiques du Canada. Elle the day in the time frames required and the traite des problèmes courants selon les documents it contains are not intended as échéanciers dictés. Les documents qu’elle definitive statements on the subjects addressed contient ne doivent pas être considérés comme but rather as progress reports on ongoing des énoncés définitifs sur les sujets traités, mais investigations. plutôt comme des rapports d’étape sur les études en cours. Research documents are produced in the official Les documents de recherche sont publiés dans language in which they are provided to the la langue officielle utilisée dans le manuscrit Secretariat. envoyé au Secrétariat. This document is available on the Internet at: Ce document est disponible sur l’Internet à: http://www.dfo-mpo.gc.ca/csas/ ISSN 1499-3848 (Printed / Imprimé) ISSN 1919-5044 (Online / En ligne) © Her Majesty the Queen in Right of Canada, 2009 © Sa Majesté la Reine du Chef du Canada, 2009 TABLE OF CONTENTS ABSTRACT..............................................................................................................................................v RÉSUMÉ .................................................................................................................................................vi INTRODUCTION ......................................................................................................................................1 PHYSICAL AND CHEMICAL OCEANOGRAPHY ..................................................................................4 Bathymetry.........................................................................................................................................4 Coastline and seafloor......................................................................................................................4 Tides ...................................................................................................................................................5 Circulation and water mass characteristics...................................................................................6 Sea Ice ................................................................................................................................................9 SHIPPING PATTERNS ..........................................................................................................................10 Import/export ...................................................................................................................................11 Sealift................................................................................................................................................12 Future outlook .................................................................................................................................14 RISK ASSESSMENT .............................................................................................................................15 General description of risks...........................................................................................................17 Risks to the ecology of Hudson Strait and the Hudson Bay complex.......................................19 Plants.........................................................................................................................................19 Invertebrates..............................................................................................................................21 Fish ............................................................................................................................................22 Marine Mammals .......................................................................................................................25 Birds...........................................................................................................................................30 Ecologically sensitive areas...........................................................................................................34 Consideration of alternatives to ballast water exchange in Hudson Strait ..............................34 Uncertainties....................................................................................................................................37 RECOMMENDATIONS..........................................................................................................................37 ACKNOWLEDGEMENTS......................................................................................................................38 REFERENCES .......................................................................................................................................38 GLOSSARY............................................................................................................................................64 ACRONYMS...........................................................................................................................................64 FIGURES Figure 1. Under the Canada Shipping Act (P.C. 2006-495 June 8, 2006) Ballast Water Control and Management Regulations, the Alternate Ballast Water Exchange Zone (ABWEZ) in Hudson Strait is located east of 70°W longitude where the water is at least 300 m deep. .............................................................................................. 65 Figure 2. Key place names in the Hudson Bay complex LME (Large Marine Ecosystem) ................. 66 Figure 4. Summer circulation of water in the Hudson Bay complex .................................................... 68 Figure 5. Summer (July-September) sea surface temperature in 2006............................................... 69 Figure 6. Summer temperature, salinity, and density across Hudson Strait from Cape Hopes Advance to Baffin Island.......................................................................................... 70 Figure 7. Summer temperature, salinity and density along a transect parallel to the axis of Hudson Strait....................................................................................................................... 71 Figure 8. Ice formation and breakup in the Hudson Bay complex over the 21 year period 1971 to 2000 ....................................................................................................................... 72 iii Figure 9. Median of sea ice concentration in the Hudson Bay LME on 1 April over the 21 year period 1971 to 2000 .................................................................................................... 73 Figure 10. Annual shipping activity in the Hudson Bay LME related to the sealift (domestic top and local bottom) and to non-sealift import and export (bottom). ................................. 74 Figure 11. Large Marine Ecosystems (LMEs) used as the last port of call for ships in ballast enroute to Churchill, Manitoba from 1998 through 2005......................................... 75 Figure 12. Composite of summer sea surface temperatures (21 June―20 September) integrated over the period 2002 to 2008............................................................................. 76 Figure 13. Summer salinity at the surface (practical salinity scale=pss). ............................................ 77 Figure 14. Ballast water exchange by vessels enroute to Churchill, Manitoba in 2005 to 2008. ................................................................................................................................... 78 Figure 15. Active metal mines and mineral exploration and deposit appraisals near the HB complex coasts ................................................................................................................... 79 Figure 16. Surface chlorophyll-a concentration (mg/m³) in Hudson Strait during August 2007 and over the summer period (July through September) of 2007............................... 80 Figure 17. Chlorophyll-a concentration in the summer of 2006 (July through September) ................. 81 Figure 18. Important concentrations of marine mammals and birds within the Hudson Bay LME and along its coasts during spring through fall (roughly March to mid- November in the south, late May to late October in the north) ........................................... 82 Figure 19. Important concentrations of marine mammals and birds within the Hudson Bay LME and along its coasts during winter (roughly mid-November to March in the south, late October to late May in the north)....................................................................... 83 Figure 20. Composite of surface water temperature (°C) in Hudson Strait over the 6-year