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Chapter 8

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Geography 2131A/B
Jamie Baxter

CHAPTER 8: OCEANS AND FISHERIES -Canada has the longest coastlines, the longest inland waterway, the longest archipelago, and the second-largest continental shelf of any country in the world -EXCLUSIVE ECONOMIC ZONE: the area of exclusive fishing rights granted to Canada in the 1982 United Nations Convention on the Law of the Sea – the zone came into force in 1994 – 200 nautical miles -area of extension of Canadian claim (beyond 200 nautical miles) possible under U.N. Convention on the Law of the Sea – as of 2002, this claim had not been initiated -wild capture fisheries valued at 3.4 billion in 2010 -aquaculture valued at 927 million in 2010 CANADA’S ARCTIC OCEAN: Canada’s coldest ocean, contains about 173,000 kilometers of coastline - majority of the area is covered seasonally by ice 1 to 2 metres of thick -maximum sunlight enters the water column in July, after the ice breaks up, limiting phytoplankton production to the late summer; as a result, Arctic waters produce only about one quarter of the organic biomass per unit area compared with that produced over the east and west coast continental shelves -major currents influencing Arctic waters include the flow of polar water southeast through the archipelago, the West Baffin Current, and the Hudson Bay gyre, a circular current that creates a small, nearly closed circulation system characterized by nutrient enrichment and high levels of biological productivity -currents help maintain open water areas called polynyas -POLYNYAS: an area of unfrozen sea water, created by local water currents in northern oceans – they act as biological hotspots and serve as vital winter refuges for marine mammals -the largest polynyas, the North Water in north Baffin Bay allows an early and persistent phytoplankton bloom -subsistence hunting and fishing does dominate the Arctic region – however, some commercial fishing does occur - the polar waters only have a certain amount of commercial fishing potential -subsistence hunting mainly by aboriginal peoples (for food and cultural continuity) -Narwall is hunted for subsistence but some people hunt them for their valued husks -arctic ecosystems are particularly vulnerable to contamination by chemical compounds because they have been transported long distances (in gaseous or vapour from the atmosphere) – these compounds are persistent and lipophilic, which means they tend to concentrate in fatty and protein-rich tissues -compounds such as PCBs and DDTs bioaccumulate readily in fatty tissues of long-lived animals at the tops of the food chains -the long and complex food web (with five trophic levels) in Arctic marine systems allows persistent contaminents to become highly concentrated in top predators – this concentration happens because predators at each higher level of the food chain accumulate the total chemical contaminent burden of all their prey -BIOMAGNIFICATION: the cumulative increase in the concentration of a chemical in successively higher levels of a food web – this explains why PCB levels in marine mammal blubber may be a million or more times higher than those in the Arctic ocean water -even locals and Inuits are vulnerable to this toxic chemicals because they are consuming the fish as well -THREATS TO ECOSYSTEM INTEGRITY IN THE ARCTIC -Hydroelectric Development: hydroelectric dams and developments in Quebec, Ontario, and Manitoba will continue to affect rives flowing to the Arctic primarily by increasing water flows and decreasing summer flows – this may also affect changes in ocean currents, nearshore conditions, nutrient availability, phytoplankton production, etc, fish migrating into the area, etc etc. -Long-Range Transport of Pollutants (LRTAP): ecosystem integrity is threatened by the long range transport of pollutants into the Canadian Arctic from agricultural and industrial activities elsewhere in the Northern Hemisphere – POPs or persistent organic pollutants (halogenated compounds), and heavy metals are the most important groups of LRTAP contaminants - these substances are difficult to metabolize and excrete, so they bioaccumulation along the food chain, culminating in top Arctic predators -Climate Change: continued changes in sea ice extent, warming and acidification of the polar oceans are likely to further impact the biomass and community of marine biota as well as Arctic human activities – the Arctic will transform into Sub-Arctic conditions; animals, ice edges, and other boundaries will shift – affecting species productivity; if ice melts, there are more waterways open to vessels which affect Canadian national security and more open to piracy and oil spills - this all will drive changes in the biodiversity, distributions and productivity of marine biota -NONRENEWABLE RESOURCE EXTRACTION: hydrocarbon contamination from drilling muds and fuel spills – industrial growth in the Arctic has increased demands for more roads and port facilities which may have severe effects on people and wildlife -CANADA’S PACIFIC OCEAN: shortest shoreline of 27,000 kilometers and has the narrowest continental shelf – as well as the warmest waters -the fusion of offshore currents creates a complex oceanographic system that mixes the waters, giving the region a very high level of productivity -over 300 finfish species occur in this region -commercial fishery employs 54,000 people and generates 700
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