Fisheries and Fishing Techniques

Overfishing

• What is overfishing?• What leads to overfishing?

• Marine fisheries systems mainly exploit… – shelves surrounding continents, to depth of 200 m– deeper waters of tropical, temperate, polar areas

• Fisheries affect marine environments by…– changing ecosystem biodiversity and functioning– changing habitats (ex: bottom trawling)

Fishing over the centuries

• Humans have been fishing for millennia. • At first, only fish with narrow coastal ranges

were at risk of being overfished. • Distance offshore and storms prevented the

overexploitation of most marine species.

Central Case: collapse of the cod fisheries

• No fish has more impact on human civilization than the Atlantic cod

• Eastern Canadians and U.S. fishermen have fished for cod for centuries

End of the Line: Part 1 - Cod

• Watch the following clip to learn what happened to cod.

• http://www.filmeducation.org/theendoftheline/key_scene_analysis.html

End of the Line: Part 2 Fishing Technology

• Watch the following clip to learn how technology has impacted modern fishery practices.

• http://www.filmeducation.org/theendoftheline/technology.html

How have things changed?

• The Industrial Revolution led to…– steam trawlers – diesel engines– hydraulic winches– inboard refrigeration– echo-sounders– access to real-time oceanographic data

• From what you saw in the video, how have these technologies impacted fishing?

The total global fisheries catch has increased

• 'The thing is we're too good right now. Technologically, not a single hunted animal on this earth has a chance.'

Professor Jeffrey Hutchings

What can be done?

Fishing has industrialized• Factory fishing = highly industrialized, huge vessels use powerful technologies to

capture fish in huge volumes – Even process and freeze their catches while at sea

• Driftnets – type of gillnet (fish swim into it, gills catch and fish cannot swim out) for schools of herring, sardines, mackerel, sharks

• Longline fishing for tuna and swordfish • Trawling : Pelagic trawling – middle water for anchovies, tuna, mackerel• Benthic trawling – bottom trawling for halibut, flounder

Purse-Seining

Purse-Seine target species

• Yellowfin Tuna• Porpoise by-catch

Pots, Traps and Creels

Small traps baited with fish which are set down on the seabed to catch crabs, lobsters and other seafloor life.

U.S. Commercial Fishery Methods

End of the Line: Part 3Subsistence Fishing

• What other impacts do technological impacts have?– Societal– Economic

• http://www.filmeducation.org/theendoftheline/senegal.html

But I don’t see a problem . . .

• Why has global catch been stable?– Fishing fleets can reach less-fished portions of the

ocean– Fleets spend more time fishing and have been

setting out more nets and lines– Improved technologies mean we catch more fish

End of the Line: Part 4Fish Farming

• What about ‘farming fish’?• http://www.filmeducation.org/theendofthelin

e/fish_farming.html

• Watch to learn about some of the benefits and risks to fish farming.

• Are there other options?

Issues

• >30% U.S. fish stocks are overexploited• For >30% of the rest, insufficient information

to determine status• As one species becomes more rare, fishermen

turn to smaller, once-discarded species: “fishing down the food web” – causes changes in age structure and genetics of populations

We are “fishing down the food chain”

…Issues

• NW: – >72,000 jobs lost due to decreasing salmon

populations– $500 million lost

• N Atlantic:– 20,000 jobs lost in 1990’s due to cod fishery

collapse– $350 million lost

End of the Line: Part 5 Marine Reserves

• How do we preserve the ocean’s fisheries?• http://www.filmeducation.org/theendofthelin

e/marine_reserves.html

• Watch to see how reserves might work.

How do reserves work?

• Increase fish biomass / total catch• Increase fish size• Decrease mortality and habitat destruction• Protect species spread outside reserves• Improve fishing and ecotourism• Others?

• Any risks or disadvantages?

Magnusen-Stevens Fishery Conservation and Management Act of 1976

• Established the 200-mile Exclusive Economic Zone (EEZ) to eliminate foreign competition

• Conserve fishery resources• Promote fishing in line with conservation principles• Regional Fishery Management Councils (RFMC’s) to

steward fisheries resources• Scientific and Statistical Committees (SSC) to provide

information for managers, but RFMC’s not required to follow their advice: overfishing and slow recovery of overfished stocks

Exclusive Economic Zone (EEZ)

• Countries have the rights to manage and extract resources from an area 200 nautical miles off the coast of its land

• Will include the continental shelf if it extends beyond 200 nautical miles.

• Can overlap, leading to dispute!• Cod Wars: UK and Iceland• Areas outside of the EEZ are fair game

for countries to fish

Related Law: Marine Mammal Protection Act (MMPA)

• Prohibits “take” of marine mammals in U.S. waters or in international waters

• Prohibits importing of marine mammals• Boats must not disturb marine mammals and

must keep at least 100 yards from whales• Some exemptions for traditional Native American

whaling• Killer Whales, gray whales, dolphins, seals, polar

bears, dugong, manatees, walrus

Exit ticket

• What is wrong with the global fisheries situation?

• What are some solutions to the global fisheries situation?

• What strikes YOU the most about what you learned today?