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Destructive Fishing Practices
Three-Dimensionality of the Seafloor
stevedeneef.photoshelter.com
blog.thesietch.org
flowergarden.noaa.gov
Destructive Fishing MethodsBottom trawlingDredgingDynamite fishingTraps
Bottom TrawlingOccurs 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
www.saveourseas.com
Bottom TrawlingBottom Trawling InfoHow a Trawl WorksTrawling on a Non-vegetated BottomTrawling in Seagrass
Effects of scallop dredgingon a gravel bottom:George’s Bank: 84 m depth
Un-fished area
Fished area 500 m away
http://oceana.org/
Effects of TrawlingHomogenizes 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 speciesReleases large pulses of carbon
Similarities with Clear-cuttingBoth activities:
Remove large amounts of biomass from the ecosystem
Alter the substratumEliminate late successional speciesRelease large pulses of carbon to the overlying
air or water
nefc1.org savethedeepsea.blogspot.com
Frequency of trawling in some representative areas
Trawling and Bycatch
www.njscuba.net
Bycatch by Gear Type
TEDs and BRDs
http://kurrawa.gbrmpa.gov.au/
Dredging
www.southlandnz.com
hatchery.hpl.umces.edu
Dynamite fishingJacques Cousteau videoDynamite fishing - humans and sharks react
Widespread in Southeast Asia, the Aegean Sea, and coastal Africa
Trap and Pot FishingUsed for lobsters, crabs, fishWide range in size of traps
www.montereyfish.comwww.coexploration.org
Habitat degradation in trap fisheries:• Damage to sessile benthic fauna/flora during
placement, fishing, and hauling
