OverfishingOverfishing

By Sofia MarchevaBy Sofia Marcheva

Ivaylo NikolovIvaylo Nikolov

Overfishing (13)Overfishing (13)

Catching too much fish for the system to supportCatching too much fish for the system to support Overfishing is a non-sustainable use of the Overfishing is a non-sustainable use of the

oceansoceans 3 types:3 types:

Growth – harvesting fish before it reaches a Growth – harvesting fish before it reaches a reasonable size to produce the max. yieldreasonable size to produce the max. yield

Recruit – not enough adults to reproduceRecruit – not enough adults to reproduce Ecosystem – when overfishing changes the Ecosystem – when overfishing changes the

ecosystem (decrease in predatory species ecosystem (decrease in predatory species increase in small fishes)increase in small fishes)

Level of Global Fish Catch (15)Level of Global Fish Catch (15) 2006 – 144 million tonnes (capture fisheries + 2006 – 144 million tonnes (capture fisheries +

aquaculture)aquaculture) 110 millions – for human consumption110 millions – for human consumption

China and Peru – largest fish catchChina and Peru – largest fish catch More than ½ of monitored fish stocks – fully More than ½ of monitored fish stocks – fully

exploitedexploited About ¼ are overexploited or slowly recoveringAbout ¼ are overexploited or slowly recovering Maximum potential of world’s capture fisheries is Maximum potential of world’s capture fisheries is

reached reached measures need to be taken measures need to be taken Scientists are concerned about the sustainability Scientists are concerned about the sustainability

of fish catches and remind that actions need to of fish catches and remind that actions need to be taken ASAPbe taken ASAP

Fishing down the food chainFishing down the food chain Hunting fishes down the trophic levelsHunting fishes down the trophic levels in the in the

food web (11)food web (11) Decline in Mean trophic level (14)Decline in Mean trophic level (14) Transition from high trophic level, big-sized fish Transition from high trophic level, big-sized fish

to small low trophic level species that live shorter to small low trophic level species that live shorter (14)(14)

Results at first in increase in fish catch, but then Results at first in increase in fish catch, but then it declines (14)it declines (14)

Fishermen tend to catch larger fishes, but then Fishermen tend to catch larger fishes, but then they become less and there is a shift to smaller they become less and there is a shift to smaller fishes (11)fishes (11)

Shows unsustainability (11)Shows unsustainability (11)

BycatchBycatch

Fish caught unintentionally while hunting Fish caught unintentionally while hunting other species(3)other species(3)

Sometimes bycatch is kept or sold(4)Sometimes bycatch is kept or sold(4)Ex. Catching bluefish while fishing striped bass(Ex. Catching bluefish while fishing striped bass(костур)костур)

Throwing back the bycatch is called Throwing back the bycatch is called discard.(4)discard.(4)

Discarding can lead to change of current Discarding can lead to change of current population of a specie(4)population of a specie(4)

Damaging fishing methodsDamaging fishing methods

Cyanide fishing- cheap and effective(9)Cyanide fishing- cheap and effective(9) Explosive fishing- using explosives to kill Explosive fishing- using explosives to kill

the fish. Major cause of reef destructionthe fish. Major cause of reef destruction Longline fishing-lined up Longline fishing-lined up baited hooks. Estimated tobaited hooks. Estimated toKill 180 000 birds worldwide(7)Kill 180 000 birds worldwide(7) Trawls- nets that catch theTrawls- nets that catch thefish by force(9)fish by force(9)

http://static.howstuffworks.com/gif/coral-reef-blasting.jpg

Bottom-trawlingBottom-trawling

Throwing a net on the sea floor by ship(2)Throwing a net on the sea floor by ship(2) The net is being dragged by the ship(2)The net is being dragged by the ship(2) Beam and otter trawling(2)Beam and otter trawling(2) Destroys reefs and sea bottom(8)Destroys reefs and sea bottom(8) http://www.youtube.com/watch?v=zikSzUhUGtAhttp://www.youtube.com/watch?v=zikSzUhUGtA

http://upload.wikimedia.org/wikipedia/en/6/6f/Benthictrawl.jpg

No-take zonesNo-take zones

Preserved areas where species are Preserved areas where species are protected(8)protected(8)

Some no-take zones are police secured Some no-take zones are police secured and difficult to enter(8)and difficult to enter(8)

They create environment for restoring They create environment for restoring ecosystems and increase of population(8)ecosystems and increase of population(8)

Aquaculture (Impact on Wild Aquaculture (Impact on Wild Species) (1)Species) (1)

AquafarmingAquafarming (cultivating most needed (cultivating most needed species and keeping them under species and keeping them under controlled conditions) vs. controlled conditions) vs. commercial commercial fishingfishing (harvesting of wild species) (harvesting of wild species)

Negative impact on wild speciesNegative impact on wild species Ex. Salmon – affects wild salmon and Ex. Salmon – affects wild salmon and

forage fishforage fish Great demand for salmon Great demand for salmon even greater for even greater for

forage fish to feed them forage fish to feed them problem for wild problem for wild salmonsalmon

Cod in NewfoundlandCod in Newfoundland

Cod population was extremely plentiful(5)Cod population was extremely plentiful(5) In 1990 the interest in cod grew larger and In 1990 the interest in cod grew larger and

the result was overfishing(5)the result was overfishing(5) Fisherman started using small ships that Fisherman started using small ships that

returned to shore every day(5)returned to shore every day(5) John Cabot found the cod John Cabot found the cod

schools and made them schools and made them

popular(6)popular(6)

http://www.dhushara.com/book/diversit/extra/cod/cod.htm

In 1951 the factories started producing super-In 1951 the factories started producing super-trawlers like trawlers like 'Fairtry' 'Fairtry' which had vast capacity(5)which had vast capacity(5)

In 1968 was the peak of catch cod-810000(5)In 1968 was the peak of catch cod-810000(5) More than 3 times larger before the super-More than 3 times larger before the super-

trawlers(5)trawlers(5) 1990s1990s-- industry industry crash(5)crash(5) Result- complete extinctionResult- complete extinction

of cod in those regions(5)of cod in those regions(5)

http://www.grantontrawlers.com/Trawlers%20Images/Fairtry-1-LH-8an.jpg

http://www.dhushara.com/book/diversit/extra/cod/cod.htm

Bluefin TunaBluefin Tuna Large migratory fish – Atlantic + Mediterranean Large migratory fish – Atlantic + Mediterranean

(17)(17) 4m, 250kg, >70km/h (17)4m, 250kg, >70km/h (17) Faces extinction (17)Faces extinction (17) Actual amount of tuna caught – uncertain (16)Actual amount of tuna caught – uncertain (16) 2008, 2009 – UN decreased the tuna season 2008, 2009 – UN decreased the tuna season

claiming that quotas have been early reached claiming that quotas have been early reached (16)(16)

Japan – 90% of bluefin tuna caught in the Japan – 90% of bluefin tuna caught in the Mediterranean (16)Mediterranean (16)

Bluefin TunaBluefin Tuna 2010 – global ban on the trade of Bluefin Tuna – 2010 – global ban on the trade of Bluefin Tuna –

unsuccessful (16)unsuccessful (16) Great arguments whether the catch will be sustainable in Great arguments whether the catch will be sustainable in

the future (16)the future (16)

http://images.suite101.com/1686405_com_bluefintun.jpeghttp://images.suite101.com/1686405_com_bluefintun.jpeg http://www.nyu.edu/projects/aphrodisias/index2.html http://www.nyu.edu/projects/aphrodisias/index2.html

Works CitedWorks Cited1. "Aquaculture." Wikipedia. Web. 15 June 2010. <http://en.wikipedia.org/wiki/Aquaculture#Impacts_on_wild_fish>.

2.2. "Bottom Trawling." Wikipedia, the Free Encyclopedia. 8 June 2010. Web. 15 June 2010. "Bottom Trawling." Wikipedia, the Free Encyclopedia. 8 June 2010. Web. 15 June 2010. <http://en.wikipedia.org/wiki/Bottom_trawling>.<http://en.wikipedia.org/wiki/Bottom_trawling>.

3.3. "Bycatch." Wikipedia, the Free Encyclopedia. 6 June 2010. Web. 15 June 2010. <http://en.wikipedia.org/wiki/Bycatch>"Bycatch." Wikipedia, the Free Encyclopedia. 6 June 2010. Web. 15 June 2010. <http://en.wikipedia.org/wiki/Bycatch>

4.4. Castro, Kathleen. "Bycatch." Rhode Island Sea Grant. Web. 15 June 2010. Castro, Kathleen. "Bycatch." Rhode Island Sea Grant. Web. 15 June 2010. <http://seagrant.gso.uri.edu/factsheets/Bycatch.html>.<http://seagrant.gso.uri.edu/factsheets/Bycatch.html>.

5.5. Century, The 19th. "Cod Fishing in Newfoundland." Wikipedia, the Free Encyclopedia. 20 Apr. 2010. Web. 15 June Century, The 19th. "Cod Fishing in Newfoundland." Wikipedia, the Free Encyclopedia. 20 Apr. 2010. Web. 15 June 2010.<http://en.wikipedia.org/wiki/Cod_fishing_in_Newfoundland>.2010.<http://en.wikipedia.org/wiki/Cod_fishing_in_Newfoundland>.

6.6. "Cod Gone." Dhushara. Web. 15 June 2010. <http://www.dhushara.com/book/diversit/extra/cod/cod.htm>."Cod Gone." Dhushara. Web. 15 June 2010. <http://www.dhushara.com/book/diversit/extra/cod/cod.htm>.

7.7. "Coral Degradation through Destructive Fishing Practices." Encyclopedia of Earth. 24 Aug. 2008. Web. 15 June "Coral Degradation through Destructive Fishing Practices." Encyclopedia of Earth. 24 Aug. 2008. Web. 15 June 2010.<http://www.eoearth.org/article/Coral_degradation_through_destructive_fishing_practices#Explosive_Fishing>2010.<http://www.eoearth.org/article/Coral_degradation_through_destructive_fishing_practices#Explosive_Fishing>

8.8. "Coral Reefs Doomed, Study Says; Centuries of Overfishing Killing Ecosystems." Common Dreams | News & Views. 2003. Web. "Coral Reefs Doomed, Study Says; Centuries of Overfishing Killing Ecosystems." Common Dreams | News & Views. 2003. Web. 15 June 2010.<http://www.commondreams.org/headlines03/0816-06.htm>.15 June 2010.<http://www.commondreams.org/headlines03/0816-06.htm>.

9.9. Destructive Fishing." CopperWiki. 8 Mar. 2010. Web. 15 June 2010. <http://www.copperwiki.org/index.php/Destructive_fishing>Destructive Fishing." CopperWiki. 8 Mar. 2010. Web. 15 June 2010. <http://www.copperwiki.org/index.php/Destructive_fishing>

10.10. "FISHING DOWN THE FOOD CHAIN." Site Has Moved. Web. 15 June 2010. "FISHING DOWN THE FOOD CHAIN." Site Has Moved. Web. 15 June 2010. <http://archive.greenpeace.org/comms/fish/part3.html>.<http://archive.greenpeace.org/comms/fish/part3.html>.

11. "Fishing down the Food Web." Wikipedia. Web. 15 June 2010. <http://en.wikipedia.org/wiki/Fishing_down_the_food_web>.

12.12. "Overfishing - A Global Environmental Problem, Threat and Disaster." Overfishing - A Global Environmental Problem, Threat and "Overfishing - A Global Environmental Problem, Threat and Disaster." Overfishing - A Global Environmental Problem, Threat and Disaster. Web. 15 June 2010. http://overfishing.org/pages/why_is_overfishing_a_problem.phpDisaster. Web. 15 June 2010. http://overfishing.org/pages/why_is_overfishing_a_problem.php

13. "Overfishing." Wikipedia. Web. 15 June 2010. <http://en.wikipedia.org/wiki/Overfishing>.

14. Pauly, Daniel. "Fishing Down Marine Food Webs." Science/AAAS. 6 Feb. 1998. Web. 15 June 2010. <http://sciencemag.org/cgi/content/short/279/5352/860>.

15. "Scientific Facts on Fisheries Latest Data." GreenFacts. Web. 15 June 2010. <http://www.greenfacts.org/en/fisheries/index.htm>.16. Somerfield, Mark. "Bluefin Tuna Fishing in the Mediterranean." European Affairs. 21 Mar. 2010. Web. 15 June 2010.

<http://eeuropeanrussianaffairs.suite101.com/article.cfm/bluefin-tuna-fishing-in-the-mediterranean>.17. "WWF - Bluefin Tuna in Crisis." WWF. Web. 15 June 2010.

<http://wwf.panda.org/what_we_do/footprint/smart_fishing/sustainable_fisheries/bluefin_tuna/>.