2011 10.5 overfishing

Catching too much fish for the system to support by reproduction.

A non-sustainable use of the oceans leading to extinction of certain species.

On a global scale we have enough fishing capacity to cover at least four Earth like planets.

Many fishing methods are so harmful that they are unsustainable in their own way.

If overfishing continues, fish populations will be reduced even more, no matter what measures are taken.

Overfishing not only depletes the fish but seriously harms marine environment.

Because the fish population has decreased so much, many other species have been placed at risk because they now lack their major food source.

Fish Stocks (1): o 52% of fish stocks are fully exploitedo 20% are moderately exploitedo 17% are overexploitedo 7% are depletedo 1% is recovering from depletion Between 1950 and 1994, the ocean fishing industry

increased the total catch by 400%. (3) Global Fish Stocks are expected to Collapse by 2050 at

Current Exploitation Rates. (3) THE CURRENT LEVEL OF GLOBAL FISH CATCH IS IN NO

WAY SUSTAINABLE!!!

Between 1950 and 1994, the fishing industry increased the total catch by 400%. (3)

Global Fish Stocks are expected to collapse by 2050 at current exploitation rates. (3)

THE CURRENT LEVEL OF GLOBAL FISH CATCH IS IN NO WAY SUSTAINABLE!!!

Fish Stocks (1): o 20% are moderately

exploitedo 52% are fully

exploitedo 28 % are overfished,

depleted, or recovering

The graph points out that current levels of fishing are obviously unsustainable.

These 10 ecosystems were studied for their MMSY, or multi-species maximum sustainable yield. Fishing below MMSY provides ecosystems with a chance to recover.

Huge negative effects on the global economy and spawns malnutrition.

Global fisheries provide about $225 - $240 billion each year.

If more sustainable practices were used, there would be a $36 billion addition to that yearly profit – 16% increase in global income.

Between 1950 and 2004, the planet's lost out on about 10 million tons of fish catch. 

20 million people a year suffer from malnutrition. Global governments spend about $27 billion a year on

subsidies to the fishing industry, 60% goes towards unsustainable fishing operations.

Cause: Commercially valuable, bigger, slower growing species have been overfished. (e.g., tuna, cod, snapper) 

Effect: They target large quantities of smaller species of fish with less commercial value. (squid, sardines, oysters, mussels, and shrimp)

Less predatory pressure

Less competition for food

Predators deprived of food source needed in order to re-establish the population

Living creatures caught unintentionally by fishing gear.

Unlike target species, bycatch is unwanted and often unused.

Bycatch may be kept or sold Might be thrown back as discard if

not usable. Handling and exposure sometimes

injure the bycatch, which may die after being discarded.

This affects the current population Influences the species’

opportunity to reproduce.

Gillnetting – A invisible to fish fine-filament net used for capturing mainly salmon, cod and sardine. Damages other species. (14)

Cyanide fishing – Cyanide is used to stun and capture live coral reef fish. Cheap and effective but illegal. (13)

Explosive fishing – the use of dynamite or other explosives to kill fish. Causes for major destruction of reef. (15)

Long-line fishing – long baited hooks used to catch swordfish, tuna, sharks, birds, and turtles. They are estimated to kill 180,000 birds worldwide every year. (11)

Dragging huge, heavy nets along the sea floor. 

Large metal plates and rubber wheels attached to these nets move along the bottom and crush nearly everything in their path.

Water life forms are very slow to recover from such damage.

Preserved areas where species are protected

Fishing or catching of other marine animals is prohibited

Help species regenerate, to restore population

Helps species which are not included in no-take zones to restore population

The farming of aquatic organisms – keeping them under controlled conditions

Reduces the worlds dependence on wild stocks of fish

Helps to feed the worlds growing population.

Negative impact on wild species

Ex. – salmon: carnivores which need protein -> comes from forage fish -> salmon wants more forage fish -> impacts survivability of wild salmon

The population of breeding tunas has been declining steeply for the past decade

Will be wiped out completely in 3 years if nothing is done

Tunas that are able to reproduce – being wiped out

The size of mature tunas has more than halved since the 1990s.

The average size of tuna caught off the coast of Libya has dropped from 124kg in 2001 to only 65kg last year.

Industrial fishing is the main reason for the problem

WWF is calling for the immediate closure of the Mediterranean bluefin tuna fishery to give the species a chance to recover.

Trying to create a marine reserve for bluefin tuna in the Balearic Islands. (17, 18)

Problem since 1700s due to human impact – growing population and economy

1890s – dams were affecting salmon runs

Hydroelectric and flood-control projects reduce area available to salmon by half

Also affected by grazing, irrigation, logging, mining, pollution, urbanization, predators

Salmon hatcheries – don’t work (21)

Salmon farms – also not very effective (21)

1. http://overfishing.org/pages/what_is_overfishing.php 2. http://see-the-sea.org/topics/commerce/overfishing.htm3. http://www.treehugger.com/files/2010/08/how-bad-is-overfishing-what-to-stop-it.php4. http://www.seafoodsource.com/newsarticledetail.aspx?id=42949905505. http://www.seaweb.org/resources/briefings/fishdownweb.php6. http://archive.greenpeace.org/comms/fish/part3.html7. http://seagrant.gso.uri.edu/factsheets/Bycatch.html8. http://food.change.org/blog/view/overfishing_hurts_economy_public_health_and_ocean_ecosystems9. http://www.msnbc.msn.com/id/32222783/ns/world_news-world_environment/10. http://apesnature.homestead.com/chapter12.html11. http://www.copperwiki.org/index.php?title=Destructive_fishing12. http://www.greenpeace.org/international/campaigns/save-our-seas-2/save-deep-sea-life13. http://www.wri.org/publication/reefs-at-risk/cyanide-fishing14. http://www.jobmonkey.com/alaska/html/gillnetting.html15. http://www.tracc.00server.com/Fisheries/blast_fishing/blastfishing_index.html16. http://www.providence.edu/polisci/students/aquaculture/environmentalimpact.html17. http://wwf.panda.org/?162001/Mediterranean-bluefin-tuna-stocks-collapsing-now-as-fishing-season-opens18. http://www.greenpeace.org/international/en/campaigns/oceans/marine-reserves/roadmap-to-recovery/Save-the-bluefin-tuna-of-the-Mediterranean-/19. http://www.pnwsalmoncenter.org/20. http://oregonstate.edu/instruct/anth481/sal/crintro1.htm21. http://www.groundtruthtrekking.org/Issues/Fisheries/Salmon.html

http://wwf.panda.org/about_our_earth/teacher_resources/own_goals/overfishing/ http://undercovercop.org/wp-content/uploads/2010/05/wwf_liikakalastus_EU_2007_eng.jpg http://www.macalester.edu/environmentalstudies/students/projects/citizenscience2008/japanwhaling/issues.html http://na.oceana.org/en/blog/2010/10/chile-reduces-jack-mackerel-overfishing http://marinebio.org/oceans/conservation/sustainable-fisheries.asp http://veganworldwidenews.blogspot.com/2009_06_01_archive.html http://scienceblogs.com/shiftingbaselines/2008/02/fishing_down_the_food_web_turn.php http://www.smugmug.com/gallery/11627606_JyU7i/1/819830271_ee3vX#819830271_ee3vX http://www.cdnn.info/news/article/a030429.html http://www.wwf.org.ph/gallery.php?filter=3 http://www2.convention.co.jp/maguro/e_maguro/e_tuna_facts.html http://web.mit.edu/12.000/www/m2011/finalwebsite/problem/present/tech.shtml http://earthhopenetwork.net/World_Governments_Adopt_Sustainable_Fisheries_Resolution.htm http://serc.carleton.edu/eslabs/fisheries/4.html http://chefsblade.monster.com/news/articles/470-are-fish-farms-the-way-to-meet-growing-fish-

consumption http://www.moyolaangling.com/content/?id=31&l1id=22&l2id=30 http://ecolocalizer.com/2009/04/15/mediterranean-bluefin-tuna-will-disappear-by-2012/ http://wwf.panda.org/what_we_do/footprint/smart_fishing/sustainable_fisheries/bluefin_tuna/

tracking_the_giants/ http://www.biology-blog.com/blogs/archives/Biology-blog/520525028-Feb-14-2008.html http://www.statesymbolsusa.org/Alaska/Fish_King_Salmon.html