File:Coast watch (1979) (20036829344).jpg

Title: Coast watch
Identifier: coastwatch00uncs_7 (find matches)
Year: 1979 (1970s)
Authors: UNC Sea Grant College Program
Subjects: Marine resources; Oceanography; Coastal zone management; Coastal ecology
Publisher: (Raleigh, N. C. : UNC Sea Grant College Program)
Contributing Library: State Library of North Carolina
Digitizing Sponsor: North Carolina Digital Heritage Center

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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
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