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Published byHarold Cobb Modified over 9 years ago
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Three-Dimensionality of the Seafloor stevedeneef.photoshelter.com blog.thesietch.org flowergarden.noaa.gov
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Destructive Fishing Methods Bottom trawling Dredging Dynamite fishing Traps
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Bottom Trawling Occurs from subpolar to tropical latitudes Occurs in public waters Few scientific studies (but increasing) Time of recovery to original structure – years to centuries www.duke.edu
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www.saveourseas.com
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Bottom Trawling Bottom Trawling Info How a Trawl Works Trawling on a Non-vegetated Bottom Trawling in Seagrass
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Effects of scallop dredging on a gravel bottom: George’s Bank: 84 m depth Un-fished area Fished area 500 m away
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http://oceana.org/
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Effects of Trawling Homogenizes sediments; eliminates microtopography; overturns, moves, and buries boulders and cobbles; leaves long-lasting grooves Crushes and buries some infauna, exposes others Removes, damages or displaces most structure- forming species Eliminates most late-successional species Releases large pulses of carbon
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Similarities with Clear-cutting Both activities: Remove large amounts of biomass from the ecosystem Alter the substratum Eliminate late successional species Release large pulses of carbon to the overlying air or water nefc1.org savethedeepsea.blogspot.com
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Frequency of trawling in some representative areas
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Trawling and Bycatch www.njscuba.net
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Bycatch by Gear Type
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TEDs and BRDs http://kurrawa.gbrmpa.gov.au/
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Dredging www.southlandnz.com hatchery.hpl.umces.edu
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Dredging Oyster Dredging in WA State
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Dynamite fishing Jacques Cousteau video Dynamite fishing - humans and sharks react Widespread in Southeast Asia, the Aegean Sea, and coastal Africa
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Trap and Pot Fishing Used for lobsters, crabs, fish Wide range in size of traps www.montereyfish.com www.coexploration.org
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Habitat degradation in trap fisheries: Damage to sessile benthic fauna/flora during placement, fishing, and hauling
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