OverfishingMila Daskalova

Alexander KrastevTeodor Peev

10/3

What is Overfishing?

Catching more fish than restorable (2)

Not sustainable – population decreases Globally, fish-catching capacity is 3x the

needed Fish-catching methods are ineffective at

preserving the balance of the aquatic ecosystems (2)

Bycatch

Nonselective fishing – other species (2)

Catching unwanted organisms Throwing them away (discards) Likelihood to survive is little (2)

Sometimes - 80% of the total catch (2)

Bottom-trawling

Method of fishing with heavy nets that are dragged over the bottom of the ocean (1)

Huge bycatch Very harmful for the seafloor organisms Destroys whole bottom communities (1)

http://nakedmaninthetree.files.wordpress.com/2009/05/before-and-after-view-of-botto.jpg

http://www.greenpeace.org/raw/image_full/international/seafood/understanding-the-problem/fisheries-problems-today/bottom-trawling.jpg

http://earthhopenetwork.net/bottom_trawling_fish_nets.jpg

Effects of Overfishing

Decrease in biodiversity (4)

Food webs disturbed Ecosystems' balance is ruined (4)

Destruction of reefs Depletion of a major food source Fishing industry ruined (4)

No-Take Zones

Areas where fishing is forbidden (3)

Ensures that: Fish populations have time to restore Fishing industry will prosper in the future (3)

4% of the Great Barrier Reef (4)

Caribbean region (3)

Other measures against overfishing

• Further restrictions on quantity of caught fish

• Better control over fishing vessels’ actions; measures against illegal fishing (5)

• More artificial fisheries - allow for less marine fishing without harming food supplies

• Abolition of inefficient methods like bottom trawling – already done in many countries (5)

http://web.mit.edu/12.000/www/m2011/finalwebsite/graphics/intro/OVERFISHINGfromPEW.gif

Endangered Species

90% of marine predators are endangered

Tuna Swordfish Skate Cod

http://boiltheocean.files.wordpress.com/2009/06/swordfish.jpg

Black Sea OverfishingLarge fish and predators (mackerel, blue fin tuna, dolphins) removed during 60’s, 70’s (6)

Small fish populations increase (not for long)Increase in plankton levels and plankton-eating jellyfish populations - jellyfish boomDecrease in species diversity (6)

Ecosystem disturbedToo much jellyfish present, becoming a dominant species Bad effect on tourism (6)

Spain – One of the Largest European Fishing Nations

It represents ¼ of the European fishing capacityThe Fishing Armada – its vessels catch more than entire nation’s fishing fleetsIt travels as far as Antarctica and AfricaThey are continuing to overfish

Work Cited1. "Bottom trawling impacts, clearly visible from space." Eurek Alert. N.p., n.d. Web. 8 June

2010. <http://www.eurekalert.org/pub_releases/2008-02/s-bti021508.php>.

2. Overfishing. N.p., n.d. Web. 8 June 2010. <http://overfishing.org/>.

3. "Overfishing." World Resources Institute. N.p., n.d. Web. 8 June 2010. <http://archive.wri.org/page.cfm?id=3060&z=?>.

4. University of Michigan. N.p., n.d. Web. 8 June 2010. <http://sitemaker.umich.edu/gc2sec7labgroup3/over-

fishing>.

5. "Overfishing." Greenpeace. N.p., n.d. Web. 8 June 2010.

<http://www.greenpeace.org/international/en/campaigns/oceans/overfishing/>.

6. Ecopath with Ecosim. N.p., n.d. Web. 8 June 2010. <http://www.ecopath.org/node/228>.