Term
•Many freshwater fisheries no longer viable:
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Definition
–Harvest prohibited to reserve the resource for recreational uses.
•e.g. walleye in Lake Erie.
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Term
•Riverine (lotic) Fisheries:
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Definition
–Coldwater fisheries < 220C in summer.
•Salmonid domain.
–Warmwater fisheries >220C in summer.
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Term
•Lake (lentic) Fisheries:
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Definition
–Permanent standing waters form a continuun of temperature conditions.
–Thus a species common in one type of temperature habitat may also be found in a fish assemblage of a warmer or colder temperature.
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Term
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Definition
–Coldwater lakes and reservoirs (higher latitude), temperature in summer < 200C. Dominated by Salmonids.
–Coolwater systems: temperature in summer 200-250C. Mix of Salmonids and Centrarchids.
–Warmwater systems: temperature in summer >250C. Diverse fish community.
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Term
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Definition
Fresh water
–These systems have cool water and warm water species in nearshore waters and above the thermocline.
–In these systems, coldwater species persist thru summer in deep cold hypolimnetic waters.
–Two-story systems are ONLY present in large deep lakes and reservoirs with a large volume of well oxygenated hypolimnion.
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Term
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Definition
–Arid West: springs fed by underground aquifers.
–Many endemic nongame species:
•Pupfish, poolfish and spring fish (Cyprinodontidae)
•Many of these fish species threatened or endangered by aquifer water extraction.
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Term
| Migratory Fisheries Resources: Anadrmous Fish resources: |
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Definition
–Pacific salmon
–Atlantic salmon
–Striped bass
–Sturgeon
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Term
| Migratory fish resources:•Catadromous fisheries: |
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Definition
•American eel: both adults (traps) and elvers (rivers) are commercialized.
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Term
| Marine fisheries resources |
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Definition
•US is the 6th largest producer of seafood in the world.
•300,000 full time jobs.
•Harvest 5 mill. metric tons fish and shellfish.
•Worth $4 bill. ex-vessel revenues.
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Term
| Marine Fisheries:–Groundfish in Atlantic coasts. |
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Definition
•Significant decline from overfishing in late 70’s.
•Magnuson Act.
•Collapse.
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Term
| Marine fisheires:―Southeast and Gulf of Mexico Reef Fishes: |
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Definition
•Species in coral reefs
•Hard-bottomed areas with boulders
•Artificial sunken structures.
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Term
| Marine Fisheries: Snappers |
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Definition
•Most stocks are overfished
•Slow growth and late age at maturity, which makes them vulnerable to declines with high fishing mortality.
•Declines in average body size of fish
•Some stocks have declined due to shrimp fishery trapping juvenile fish (by-catch).
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Term
Marine Pelagic Fisheries: small bodied fishes
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Definition
•Small bodied species of fish or squids that school.
•Menhadden produces one of the highest catches by weight of any single species fishery in US water , captured by purse seine.
–900,000 metric tons/yr
–Fish meal, oil and bait for other fisheries.
—Pacific sardine, northern anchovy, Pacific herring.
—In 1930’s Pacific sardine supported the largest fishery in the western hemisphere. Declined after WWII and collapsed in the early 60’s.
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Term
| Marine Pelagic fisheries:Large Bodied fishes |
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Definition
–Highly migratory fishes (tunas and bill fishes, swordfish, marlin.
–Shark fisheries:
•Longline and gillnets used.
•Three management groups:
–Large coastal sharks: white, tiger, lemon, great hammerhead, bull, etc.
–Small coastal sharks: sharpnose, finetooth, bonnethead, etc.
–Pelagic sharks: mako, thresher, porbeagle, etc.
»Mako and porbeagle for human consumption, large sharks only for fins.
»Susceptible to overfishing because of low fecundity and late-age-at-maturity.
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Term
| Marine Shellfish fisheries: |
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Definition
Bivalve mollusks and crustaceans federally managed in waters 3-200 miles from coast.
•Northeast and Midatlantic Region:
•American lobster, sea wscallop, northern shrimp, surf clam, ocean quahog.
•Southern Atlantic and Gulf of Mexico Region:
•Brown, white, pink and other shrimps, spiny lobsters, stone crabs.
Stocks of some of these resources are depleted due to overfishing: American lobster, sea scallops, all shrimp stocks.
Surf clams and ocean quahogs maintained at levels that provide maximum long term harvests.
–Alaska: eastern Bering Sea and Aleutian Islands.
–Have supported commercial foreign and domestic shrimp fisheries.
–All these stocks have declined since the 60’s and 70’s.
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Term
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Definition
–Over 80 species of demersal (benthic) fishes in federal waters off California, Oregon and Washington.
–Mid-water trawl have harvested over 286,000 metric tons/yr of pacific whiting (hake).
•US harvesters sell their catch directly to foreign processing vessels by governments agreement.
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Term
| Alaskan continental shelf fisheries |
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Definition
—Abundant groundfish resources:
—Walleye pollock is the largest species catch in the Pacific.
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Term
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Definition
—Snappers, jacks, groupers.
—400,000 metric tons/yr
—Fishery depressed to less than 30% of their original abundance.
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