Wednesday, October 20, 2010

2010 Marine Ecosystem Status and Trends Report -- Canadian Science Advisory Secretariat

This report from the Canadian Science Advisory Secretariat (Science Advisory Report 2010/030), dated July 2010 finds:

 The status and trends of Canadian marine ecozones are changing owing to a suite of different factors.
 Biological and ecological effects (e.g. increased natural species mortality, species range expansions and contractions, and changes in fish size, assemblages, and community structure) are occurring; however their impact on ecosystems is not always well understood.
 Climate change and oceanographic variability are affecting most Canadian marine ecozones. In particular, ocean acidification is known to be impacting several ecozones and is an emerging issue in the others.
 A decline in many fish stocks has occurred on the Atlantic and Pacific coasts as a result of commercial overexploitation. Although management measures have been implemented for most species, recovery has been limited in most cases.
 Legacy contaminants, like polychlorinated biphenyl (PCB) and Dichlorodiphenyltrichloroethane (DDT) for example, are decreasing, however the incidence of emerging contaminants (e.g. brominated flame retardants) are becoming an issue in most ecozones.
 Industry and development have, or are threatening to, impact most ecosystems. The coastal zone is particularly vulnerable and is of concern as these areas are considered highly productive ecosystems.
 Some marine mammals that were overexploited in the past are now recovering. For example: bowhead, beluga, and narwhal in the Arctic, and sea otters, stellar sea lions, harbour seals, killer whales, humpbacks, and gray whales in the Pacific.
 Populations of grey seals in the Gulf of Maine and Scotian Shelf ecozone and harp seals in the Newfoundland-Labrador Shelves ecozone have increased dramatically.

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