1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

15

disperse the polluting substances."3 9

Manufacturing plants are also responsible for adding

chemical substances, such as the aforementioned PCB, into water supplies. Another type of

industrial pollution is carried out via dumping waste and sewage into waterways. "Around the

world, untreated sewage flows into coastal waters, carrying organic waste and nutrients that can

lead to oxygen depletion, as well as disease-carrying bacteria and parasites that require closing

beaches and shellfish beds."4 0

The major damaging aspect of the fishing industry on oceans is the practice of trawling,

which is "dragging nets along the ocean floor, [causing] devastation to sea life."4 1Of course, "as

much as 70 percent of sealife scraped up in the nets is not "usable" or sought by the trawlers. 

These dead and dying "non-target" fish and marine animals are tossed back into the ocean."4 2

The concept of "competitive exclusion," as discussed in Pinet's Invitation to Oceanography,

outlines the impact humans have on the fragile ecosystem. "The result is mass extinction of

many species."4 3Furthermore, the fish that are left in the oceans are "smaller and fewer," 4 4thus

supporting the implication that resources are limited. For example, "the average weight of

swordfish today is 90 pounds, down from over 250 pounds in the 1960s."4 5

The fishing industry not only takes away essential facets of the ecosystem, but it adds

non-essential entities, such as dangerous debris. "Fishing gear, accidentally lost or intentionally

discarded, remain an important component of persistent marine debris."4 6This lost or discarded

gear continues to be a problem for marine life, as many animals become entangled in the nets.

39 http://www.infoplease.com/ce6/sci/A0861889.html.
40 http://seawifs.gsfc.nasa.gov/OCEAN_PLANET/HTML/peril_sewage.html.
41 http://www.sfgate.com/cgi-bin/article.cgi?f=c/a/2002/03/19/MN41978/DTL.
42 http://www.eco-pros.com/humanimpact.htm.
43Chapter 13 "Oceans, Habitats, and Their Biota" in Paul R. Pinet's Invitation to Oceanography, 2 ndEd. (orig. publ. 1999; Massachusetts: Jones and Bartlett Publishers, 2000), p. 448.
44Chapter 15 "The Human Presence in the Ocean" in Pinet's Invitation to Oceanography, p. 496. 45 http://csmweb2.emcweb.com/durable/1998/01/29/feat/food.1.html.
46 http://www.mindfully.org/Plastic/Ocean/Plastics-Impacts-Marine-Andrady6aug00.htm.