Lecture 21 - 3/31/2011 Outline Aquatic Resources Oceans...

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Unformatted text preview: 3/31/2011 Outline Aquatic Resources Oceans ENV200H1S March 31, 2011 Human Impacts on Oceans Case Studies: Canada as a fishing nation Northwest Passage 1 The Global Ocean 2 Human Impacts on the Ocean Covers 3/4 of Earth’s surface Essential to hydrologic cycle Vast wilderness No nation owns the open water Ocean is overused Tragedy of the Commons How do we impact the ocean? 3 4 Ocean Dumping Pollution & Deteriorating Habitat The ocean is a dumping ground Pollution from land Runoff in rivers Atmospheric contaminants Several Canadian cities dump sewage Plastics are a real problem problem Trash collects in certain areas 5 6 1 3/31/2011 Shipping Ships dump oily ballast and other wastes MARPOL bans marine pollution from shipping Six types of marine pollution Not well enforced in open ocean Some estimate 10% of all plastics End up in Oceans Great Pacific Garbage Patch 7 8 Coastal Development Impacts on Coral Reefs Many coastal areas highly over developed Habitat is destroyed 3.8 billion people live near a coastline 3/4 of world population live within 93 miles of a coastline by 2025 About ¼ of all reefs at high risk Silt smothers reefs Overfishing, tourism Warming bleaching 9 10 Climate Change Offshore Resource Extraction More interest as easier sources depleted and technology getting cheaper Who owns those resources? resources? Offshore oil poses threats 11 Could influence patterns of oceanic circulation Rise in sea levels Oceans expected to become more acidic 12 2 3/31/2011 World Fisheries Ocean provides a lot of food Oceans are the only places on earth where wild species of animals are commercially exploited exploited on a large scale Fish account for roughly one fifth of all animal protein in the human diet Around 1 billion people rely on fish as their primary protein source Many species are overfished 1950: 19 million tons of fish 2005: ~158 million tons of fish More than two-thirds of the world's twomarine fish stocks are being fished at or beyond their level of maximum productivity. 13 14 Fisheries as a classic “tragedy of the commons” Therefore the incentive is to: A fishing company: has no effective property rights competes for shares of the same fish as everyone else everyone else rationally calculates that any fish left in the else water will be caught by somebody else as long as the quota remains open "mine" the resource as rapidly as possible (without regard to its sustainability) increase fishing power to maximize the catch per unit of effort (because there (b is no assurance of a given share of the allowable catch). 15 16 New technology: the factory ship/trawler The The end actually begins with the development of the distant water factory trawling fleets in the 50s 17 use trawl type nets catch, process and freeze fish at sea fraction of world’s fishing fleet (< 1%) catch most of the world’s fish (>50-60%) (>50400 tonnes of fish per trawl highly mobile and can stay at sea for up to 2 months state of the art tracking Foot rope scrapes the seabed Overturns boulders, breaks up coral and crushes plants and animals Indiscriminate 18 3 3/31/2011 Over capacity and the imperative to waste Factory trawlers waste more fish than other vessel classes through bycatch Over capacity means trawlers reach quota more quickly Once storage holds are full, the trawler must return to port to offload (in that time the quota could be reached and the season closed) 19 19 20 Canada as a fishing nation So. . . . Discard bycatch in favour of target species Discard target catch that are too small for that are too small for the the automatic processing machines (fleet pays nothing so there is no loss in thowing away all but the choicest fish) In 2.2 billion kg pollock catch •7.7 million kg halibut •1.8 million kg herring •200,000 salmon •360,000 king crab •15% target wasted Commercial fishing in Canada dates back over 500 years 21 22 Child with two cod (Battle Harbour, Labrador 1910) Harbour, Once the majority of fishers were in-shore owner-operators, there were 30 kg chinooks on the west coast and 90 kg (!) cod on the (!) th east coast. Sadly that’s not the picture of fishing in Canada today! National Archives of Canada; Neg. No.: C76178 Record cod = 183 cm, 95 kg 23 24 4 3/31/2011 What happened off Canada’s east coast . . .? After a sustained harvest over 500 years . . . 1992: cod collapse loss of 40,000 jobs fishing as fishing as a % of GDP falls from ~1.7 to of GDP falls from 1.7 to ~0.2 ~0.2 . . .and continues to happen with those global fisheries that remain? 26 25 Over capitalization The fishery • In the crucial 1960s, government subsidies “modernized” fishing fleets. • Low interest loans covered 50 to 80% of costs • Repayment periods ranged from 6 to 20 years • In Canada, there were: • outright grants for purchasing boats or gear (when loans failed to stimulate sufficient private investment) • guaranteed loans for the entire mortgage on boats. • construction of fish processing plants (e.g. National Seafood) Past generations of local fishers using small-scale fishing boats and long lines (cod jigging) were the primary providers of fish on the Canadian (and US) east coast (the “in-shore” fishery) With the closing of the fishery, 40,000 people in Newfoundland & Labrador 27 were thrown out of work. • Relief from taxes and from import duties on fishing vessels, gear and equipment 28 Role of Fisheries Scientist Total Allowable Catch Develop information on biology and population dynamics of fish stocks Stock assessment: Age structure Movement/migration abundance Life history strategies Growth rates Mortality rates (natural, fishing) interrelationships with other species association with physical environmental factors Sets TAC, ITQs, effort restrictions, e.g. mesh size min/max, vessel size, season limits, etc. The quantity of fish that can be taken from each stock each year. Balance between use and conservation of resource Based on concepts of Maximum sustainable yield: 29 1) The largest long-term average catch or yield that longcan be taken from a stock or stock complex under prevailing ecological and environmental conditions. 2) Maximum use that a renewable resource can sustain without impairing its renewability through natural growth or replenishment. 30 30 5 3/31/2011 Despite vigorous arguments to the contrary from both inshore fishers and their own fisheries scientists, Canadian politicians, unable/unwilling (?) to deal with the implications of massive unemployment, op opted for the upper bound of the TAC th TAC rather rather than the lower and appear to have been simply hoping for the best (or ignorant of the implications of their choices) Some Proposed Causes of Collapse overly high Total Allowable Catch (TAC) levels; under-reporting of actual catches; destructive fishing practises; Domestic and foreign overfishing; and, Environmental factors. 31 31 Overfishing The Future 32 Recovery is not certain Why Not? Despite limiting fishing mortality, natural natural mortality mortality remains relatively high Seal predation? Poor environmental conditions? Cascades down through the aquatic system drives changes in density of krill/phytoplankton Propagates along the food chain Losses of top mammal predators (Steller sea lion) Losses in sea birds bi (kittiwakes, murres, (kittiwakes, murres, puffins) 33 34 34 35 35 36 Exclusive Economic Zone (1976) The Exclusive Economic Zone extends 200 nautical miles from the baseline. Canada may exercise its rights and responsibilities responsibilities with respect to the exploration and and exploitation of living and non-living nonresources of waters, subsoil and seabed. Within EEZ, Canada has the responsibility and jurisdiction to protect the marine environment, to regulate scientific research and to control offshore installations and structures. 6 3/31/2011 Why does it matter? The Arctic Ocean and the Northwest Passage Fish respond to physiography not jurisprudence We could (theoretically at least) do a better job managing the Atlantic and Arctic fisheries if the EEZ included the entire continental shelf (particularly the nose and tail of the Grand Banks in the Atlantic) Potential for oil and gas il A U.S. Geological Survey reports suggests the Arctic holds up to 13% of the world's undiscovered oil and possibly 30% of the world's undiscovered gas reserves 37 37 As the ice in the Arctic archipelago shrinks, sovereignty over the Northwest Passage is becoming a hot political issue The passage offers a shipping route between Asia and Europe that is 7,000 km shorter than through the Panama Canal (e.g. Shanghai – Rotterdam is US $590 000 cheaper) cheaper) It could also accommodate supertankers and other vessels too large to make it through the Panama Canal Will these narrow passages among our northern islands become international straits (as many including the US and the EU contend) or should they contend) be considered Canadian waters? 38 The five littoral states—Canada, states— Denmark, Norway, Russia and the United States So of course, utility maximization leads to overlapping claims! 39 39 40 7 ...
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