decade later, when floating plastic par- 

 ticles were found throughout the north 

 Atlantic Ocean, were the potential prob- 

 lems fully recognized. 



Today, we separate the impacts into 

 two broad categories: biological and 

 economic. 



Biological studies tell us that 

 waterbome debris casts a wide net of 

 impact over marine and littoral animals, 

 plants and perhaps even entire ecosys- 

 tems. It entangles wildlife, masquerades 

 as a food source and smothers benthic 

 and beach plants. 



The most obvious of these biologi- 

 cal impacts is entanglement, although it 

 is also difficult to measure. We get fleet- 

 ing glimpses of entangled animals from 

 planes and ships, but these cases are not 

 well documented or systematically sur- 

 veyed. Many victims die and sink or are 

 eaten; others float under debris. Conse- 

 quently, entanglement data is collected 



on the beaches where survivors strand 

 or congregate to nest, away from the 

 actual problem. 



Worldwide, at least 135 species of 

 marine vertebrates and eight inverte- 

 brates have been reported entangled in 

 marine debris. Still, the measured fre- 

 quency is low — usually less than 1 

 percent of an affected species — espe- 

 cially when compared to ingestion. 

 These rates may, however, exceed esti- 

 mates from land-based observations. 



For certain species, entanglement 

 appears to occur regularly. 



Some — gray whales, California 

 sea lions, northern elephant seals, north- 

 em gannets, herring gulls and shags — 

 have healthy populations that don't 

 seem to be compromised by low levels 

 of entanglement deaths. This is not true, 

 however, for endangered or threatened 

 species — manatees, Steller sea lions, 

 hawksbill sea turtles and olive ridley sea 



turtles. Even though entanglement 

 deaths may be low compared to other 

 human-related causes, they add ob- 

 stacles to recovery. And for a few spe- 

 cies — Hawaiian monk seals, green sea 

 turtles and northern fur seals, certain 



The answer — 

 a resounding chorus from scientists, 

 resource managers and concerned 

 citizens of all tongues — 

 is a global commitment 

 to measure marine debris 

 and its impacts, trace its sources 

 and stop it in its path. 



fish and crabs caught commercially, and 

 perhaps northern right whales — it oc- 

 curs often enough to affect population 

 numbers. 



The frequency of entanglement is 

 influenced by the density of debris in an 

 area and an animal's food preferences, 

 feeding habits and behavior. Young 

 seals, for instance, like to play with 

 debris; birds use it to build nests; and 

 turtles often become entangled in debris 

 that they're trying to eat. The shape and 

 size of debris also have a bearing on its 

 ability to trap animals. Nets and ropes, 

 monofilament line, strapping bands and 

 other ring-shaped objects are common 

 culprits. Large items can trap animals, 

 drowning air-breathers, asphyxiating 

 fish that require motion to respire, starv- 

 ing them or making them vulnerable to 

 predation. Smaller debris drags from the 

 bodies of entangled animals, increasing 

 the energy they need to move around 

 and reducing their ability to forage and 

 escape predators. 



More commonly, however, animals 

 eat plastic rather than become trapped in 

 it. Plastic in the water looks like food to 

 many of them. Turtles mistake bags for 

 jellyfish, one of their favorite meals. 

 Birds mistake pellets for fish eggs. 



Other times, plastic is eaten in asso- 

 ciation with food that has been dumped 

 from ships or consumed within contami- 

 nated prey. 



At least 160 species of vertebrates 

 — approaching 100 percent of some 



