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44 Cards in this Set
- Front
- Back
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What could fisheries be causing?
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The extinction of fish
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What was the World Marine Fish Harevest in 1950 and in 1989
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21 million metric tons,
86 million metric tons. Quadrupled |
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What is a Maximum sustainable yield?
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Amount that can be caught without affecting future yields
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How did the amounts of fish fed to humans and to livestock change since 1950?
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More fish fed to livestock now
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Why is feeding fish to our future food sources bad?
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Adds another level to the foodchain, decreases ecological efficiency
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What is true for 70% of marine stocks today?
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Overfished, depleted, or rebuilding
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What do cod eat?
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Bottom feeders: crabs, squid, clams, small fish
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How long until cod are adult, and how long do they live?
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3-7 years, 20-25 years
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What 3 different methods have been used through history to catch cod?
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Handlines,
long lines with hooks trawls |
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In the 1950s, what countries started using factory trawlers and where?
What happened to the yields? |
USSR, UK
on Newfoundland Banks Yields decreased from 800,000 tons to 200,000 tons/year |
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What did US and Canada do to their Exclusive Economic Zones?
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Extended them from 3 to 200 miles. Home fishermen replaced foreigners
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What eventually happened to cod fishing?
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Canada banned commercial fishing in Newfoundland, National Marine Fishery Service closed cod fishery in 1994
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Where are cod and haddock fisheries banned in Europe?
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North Sea, Skagerrak, Irish Sea, West Coast of Scotland
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Why are trawlers bad for corals?
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Scrape away habitat for future generations to live
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What animal did people start catching once traditonal fisheries were depleted?
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Sharks
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Why are shark populations decimated?
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Caught for sharkfin soup.
Low reproductive rates and long maturation periods |
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Where are salmon fisheries?
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Pacific NW and Alaska
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Salmon: where do they spawn, how long do they stay there, then where do they go and how long do they stay there?
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Spawn in FW
1 year in rivers Go to sea 1-4 years at sea |
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What is it called when salmon return home to spawn?
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chemotaxis
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what are problems for salmon fisheries?
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hydroelectric and flood control dams.
timber wastes |
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What are hatcheries? and why are they good?
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eggs hatches and juveniles released after a year.
supplement wild populations |
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Where are peruvian anchovy fisheries?
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coastal upwelling
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What are peruvian anchovies used for?
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fishmeal
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What event devastated the peruvian anchovy fishery?
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El nino- nutrient upwelling stopped
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What is by-catch wastage?
What is a by-catch of Shrimp nets? What is a by-catch of pollock and cod trawling? |
When trawling, legally have to discard species that you arent liscenced to catch.
Turtles halibut, salmon, king crab |
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What are 3 problems of fisheries?
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by-catch wastage, gill nets, highly effective detection methods
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Why are gill nets bad?
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nondegradable
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What is a highly effective detection method?
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satellites for tuna
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An increase in the amount of _____ is part of the cause of overfishing
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ships
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what are 5 remedies to the overfishing problem?
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fish sanctuaries, habitat protection, fishing methods, recuperatie bans, licensed catches
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What is the difference between aquaculture and mariculture?
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Aquaculture in Freshwater
Mariculture in Seawater |
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On What continent is aquaculture successful?
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Asia
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How are bivalves grown in aquaculture
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on submerged rafts
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What are some problems for salmon raised in floating pens?
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spread diseases to wild fish,
antibiotics enter marine regions, pink meat instead of red, lower levels of polyunsaturated fatty acids |
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What are three endangered marine mammals?
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Manatees, seals, sea otters
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In 1900, where did whalers move to and from where?
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To Antarctic from N. Atlantic
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What happened to Blue whale population in 1930 and 1962
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1930- less than 4% of original levels
1962- down to 1000 |
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In whaling, factory ships negated the need for ______
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shore-based processing stations
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What happened to commercial whaling in 1985
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moratorium by International Whaling Commission
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Which great whales are severely depleted?
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blue, right, humpback, finback, bowhead, sei
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what great whales have been recovered or sustained?
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sperm whale, gray whale, minke whale
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What can cause marine mammal strandings?
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-High intensity sonar
-Microbial or viral infections -pollutant accumulation in fatty tissues |
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What are problems for dolphins?
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Japanese eat them
Used as bait in South America Caught in tuna nets Psychologically stressed by marine parks |
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How do dolphins get caught in tuna nets?
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They feed on tuna, so fishermen follow them. they get caught in nets, suffocate.
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