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RESOURCES FROM EARTH’S WATERS
OCEANS, BAYS, LAKES,RIVERS PONDS, STREAMS ETC.
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WORLD POPULATION
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How Much of Our Food Supply Comes from Earth’s Water
1% of food comes from the sea Earth’s Waters Supply 10% of the protein consumed by humans
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Kinds of Food From Earth’s Waters
Finfish – make up 85% of world catch followed by shellfish (mollusk and crustaceans) Finfish come from - 86% ocean, % freshwater Shellfish- 15% mostly from the ocean
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Kinds of Food From Earth’s Water cont’d
Freshwater fisheris comprise 18% of the global catch, and it is growing! Seafood accounts for 15% of the total animal protein consumed worldwide!! (a very large number considering only1% of food comes from the sea/rivers/lakes.
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Types of Fish and Shellfish
Benthic and Demersal – live at or near the bottom of the sea in COLD Waters (ex. Flounder, lobsters, crabs, whiting) Clupeoid – live in schools near surface on continental shelf ex. Herrings (sardines), Menhaden, Shads Pelagic – Open water fish (ex. Squid, Tuna, Swordfish)
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Benthic Fish KING CRAB Live at or near the bottom of the sea
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COLD WATER DEMERSAL FISH
Live near or around the bottom of the continental shelf Examples Cod, Pollack, haddock, hakes, whiting Caught in trawls
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COD
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WHITING
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POLLACK
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Benthic Fish Flounder Flat fish Eyes on one side Camouflage to
match color of the sand
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Benthic Fishing Techniques
Caught with trawls-dragged along the bottom of the sea. TRAWLING
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FISHING TECHNIQUES TRAWLING
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Cod Fishery-Threatened!!
1992-Grand Banks placed moratorium (ended) the cod fishery to save them from extinction. 1994-Georges Bank fishery off New England closed their operations also. Experts predict the cod will NEVER recover!!!
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CLUPEOID FISH SARDINES – travel in schools near the surface & along continental shelf
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CONTINENTAL SHELF
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CLUPEOID FISH Sardines, shad, herring, menhaden etc. Live in schools
Found over continental shelf Caught using purse seines Eaten fresh, canned or pickled Ground into fish flour or Fish Protein Concentrate
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Fishing Techniques Purse Seine Nets
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FISHING TECHNIQUES PURSE SEINE
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CLUPEOID FISH Used to produce fish oil
Used to make fish meal for poultry feed Used to make fertilizer Industrial catches may result in overfishing because they naturally fluctuate in population and fisherman are unaware of their low cycles 1940’s sardine fishery collapsed
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Purse Seine Catches
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CLUPEOID FISH HERRINGS
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CLUPEOID FISH MENHADEN
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Sardines and Anchovies
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PELAGIC FISH Open Water Fish
Billfish (Striped marlin, Blue marlin, Black marlin Sailfish, Swordfish) Tuna (Yellowfin, Skipjack, Bonito) Jacks (Yellowtail, Amberjack) Dolphinfish (Dorado) Mako shark
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Tuna
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TUNA Skipjack, yellow fin, big eye, albacore, blue fin
Eaten raw in sashami Caught in gill nets, large sienes and long lines Blue fin can sell for up to $ a pound Tuna population is down 10% Fish nations would not declare it an endangered species, but in 1995 agreed to restrict catches to 50% of current catches
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Fishing Techniques-Pelagic Fish
Pelagic Fish are caught using large seines, surface longlines and gill nets.
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COMMERCIAL FISHING IN THE PAST
Early fishing methods
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FISHING TECHNIQUES
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FISHING TECHNIQUES LONG LINES-Pelagic Fish
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LONG LINES-Pelagic Fish
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FISH NET
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GILL NET-Benthic/Demersal Fish
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Marlin
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SKIPJACK TUNA
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Blue Fin Tuna
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YELLOW FIN TUNA
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YELLOWFIN TUNA
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ALBACORE TUNA
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SWORDFISH
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MAKO SHARK
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FINNING Many sharks Are caught and Killed ONLY For their fins!!
Then thrown Back into the Water to drown/die at sea. Fins sold to China for Shark Fin Soup
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HW-Textbook pages 355-377 Questions on Resources from the Sea Chapter.
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Total Marine Catches from 1990 to 1995
(million tons) 1990 (million tons) 1995 Fishes 69.36 73.07 Mollusks 7.73 10.61 Crustaceans 4.50 5.65 TOTALS 97.97 112.91
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MOLLUSK Second to finfish, mollusks are the most valuable food source
Mollusks-Soft-body protected by a calcium carbonate shell. Largest catches include clams, scallops mussels, oysters, abalone, squid, and octopus
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MOLLUSKS
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Fishing for Mollusks Shellfish-clams, oysters, scallops are caught using a scallop dredge or traps sitting on the seafloor.
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SCALLOP DREDGE
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Pink Spiny Lobster
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LOBSTERS, CRABS AND SHRIMP
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CRUSTACEANS Crabs Lobster Shrimp
Caught in traps and trawls that are dragged along the seafloor.
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LOBSTER TRAP
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LOBSTER IN TRAP Lobster and Crab Fishing Today
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SEAWEED Varieties of freshwater and marine algae are popular as a food source in the far east Often used in sushi, sashimi, and soup
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SEAWEEDS Seaweed is used in many cultures. It can be consumed raw, cooked, dried. Contains substantial amounts of protein
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SEA URCHIN (UNI) Roe (eggs and organs that make the eggs) demands an incredibly high price in $$ Japan
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Caviar Caviar is an expensive delicacy consisting of the unfertilized eggs (roe) of sturgeon brined with a salt solution .
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STURGEON
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SEA CUCUMBERS Called TREPANG OR BECHE-DE-MER are dried, smoked, or eaten raw in orient
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JELLIES Jellies are dried and eaten in China
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POLYCHEATE WORMS Eaten in South Pacific
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Lab-Medicines from the Sea p.176
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SEA TURTLES Sea Turtles and their eggs are eaten wherever found
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SEALS AND WHALES Still eaten, particularly in Arctic, West Indies, and South Pacific
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MINKE WHALES
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BELUGA WHALES
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NEW YORK STATES ENDANGERED FISH SPECIES
Shortnose Sturgeon Silver Chub Pugnose Shiner Round Whitefish Bluebreast Darter Gilt Darter Spoonhead Sculpin Deepwater Sculpin
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How Much Fishing is Too Much?
Optimal Catch vs. Over-fishing Renewable Resources are composed of living organisms that can reproduce and replace individuals lost to disease and predators including humans. Nonrenewable resources would not be replaced naturally and would include oil and minerals.
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Over-Fishing Catch them faster than they reproduce.
A population of fishes are over-fished and the stock ( size of population) is reduced to a level which can still reproduce successfully, fisheries will cease to exist for a short time, then rebound.
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Successful Reproduction
Depends on a Proper Stocking Too many organisms lead to overcrowding, excessive competition, and depletion of food resources. Too few organisms produce too few young to maintain a proper self-sustaining stock. Fish do best when there are not too many and not too few. OPTIMAL *
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MAXIMUM SUSTAINABLE YIELD
The amount of fish that can be caught and just balance the growth of the population. Catch just enough fish to prevent population growth, but not enough to reduce the population.
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Maximum Sustainable Yield Graph
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PROBLEMS WITH MAINTAINING MAXIMUM SUSTAINABLE YIELD
Fisheries strive to exceed maximal sustainable yield or optimal catch. Overfishing has already affected almost all commercial fisheries. Stocks of cod, haddock, herring, halibut, shark, and wild salmon are in danger. Fish stocks are damaged by pollution from oil spills, sewage, and toxic chemicals.
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Problems Determining Maximum Sustainable Yield
Not easy to determine Variation caused by catching fish when they are too young or catching them before or after breeding season may make all the difference. No exact science about regulating stocks of fish
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Problems from the Past Sardines
1940-Pacific Sardine fishery collapsed due to heavy fishing that coincided with a low point in their reproductive cycle.
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Problems of Today Bluefin Tuna
Tunas-Northern bluefin tuna; one of the largest bony fish is very valuable. Their popluation is down to less than 10% of their former numbers in the Western Atlantic. Nations are slow to respond, refusing to list it as endangered. 1995-Agreed to reduce catch limits by 1/2
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Problems of Today Swordfish
Swordfish-Close to commercial extinction. Stocks fallen 70% since 1960. 88% of swordfish caught in 1995 were too young to reproduce!!!
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Other Threats Pollution: Oil spills Sewage overflow Toxic Chemicals
Fertilizer/pesticide runoff into oceans/lakes Habitat loss Destruction of breeding grounds
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Possible Remedies Set fishing limits below what we think is the optimal catch Limit the length of fishing season Restricting the size or number of boats Regulating the size and the sex of fish caught Certain methods of fishing can be eliminated (ex. Trawls) or size of nets
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MORE REMEDIES Control the areas of the sea to be fished
Safe fish farming
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Fishing and Life Many people are effected by the success or failure of fisheries Cannery Dock workers Boating and fishing gear industries Bankers Fisherman Local businesses
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Regulations 1989 United Nations Convention on the Law of the Sea established a 200 nautical mile ( 1 nm = 1.15 miles) exclusive economic zone. (EEZ) Within this zone each country controls fishing, oil, and mineral resources.
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New Fisheries Create a market to use “junk fish” or “Bycatch” such as Alaskan Pollack, Monkfish, Croakers, and Sea Robins will be consumed. They are presently used to make fish flour, fish sticks and enrich processed food.
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Industrial Fisheries Catch is used for purposes other than human consumption (fish oil, margarine, paint, pet food, fertilizer) Industrial fisheries account for over 1/3 worlds total fish. Most clupeoid fish are used for FPC or fish flour.
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Aquaculture Fish Farming
Can reduce pressure on the oceans for protein It is the commercial breeding and raising of fish for human consumption. Chinese have farmed freshwater fish for thousands of years Romans have raised oysters Videos\Aquaculture safer method.asf
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Fish Farm
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Catfish Farming
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Fish Farming Benefits Provide a plentiful inexpensive source of food specifically protein for a large population Easier and can be less expensive than catching wild fish May help prevent extinction of some species
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Limitations and Problems with Fish Farming
Only a small number of fish species can be farm raised Clupeoid fishes need open ocean spaces and would not survive on a farm Parasites and diseases are a concern Cannibalism Need expensive filters and pools free of pollution
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Limitations and Problems of Fish Farming
Use of artificial feed sources (ex. Chicken feed or Junk Fish) Concentration of Carcinogens (ex. PCP ) in some populations. Effect on local environment
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Salmon Farming Hatch in freshwater habitats from 0-18months
At 18months they are moved offshore into pens in the ocean. Stimulates normal lifecycle.
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Salmon Farming-Problems
Waste concentrates and builds up in surrounding water. Disease spread quickly and easily to other fish and fish that are not in the pen. Chemicals given to salmon (antibiotics) may affect humans. Farmed salmon have higher levels of PCB, toxic to humans!
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Salmon Farming Problems
Sea lice-parasites on fish
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Video Clips Videos\Fish_Farms.asf Videos\Fish_Farming_.asf
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