School of Biological Sciences, Moreton Bay Research Station, University of Queensland, Dunwich, Queensland, Australia.
PLoS One. 2012;7(7):e40884. doi: 10.1371/journal.pone.0040884. Epub 2012 Jul 19.
Marine debris is a growing problem for wildlife, and has been documented to affect more than 267 species worldwide. We investigated the prevalence of marine debris ingestion in 115 sea turtles stranded in Queensland between 2006-2011, and assessed how the ingestion rates differ between species (Eretmochelys imbricata vs. Chelonia mydas) and by turtle size class (smaller oceanic feeders vs. larger benthic feeders). Concurrently, we conducted 25 beach surveys to estimate the composition of the debris present in the marine environment. Based on this proxy measurement of debris availability, we modeled turtles' debris preferences (color and type) using a resource selection function, a method traditionally used for habitat and food selection. We found no significant difference in the overall probability of ingesting debris between the two species studied, both of which have similar life histories. Curved carapace length, however, was inversely correlated with the probability of ingesting debris; 54.5% of pelagic sized turtles had ingested debris, whereas only 25% of benthic feeding turtles were found with debris in their gastrointestinal system. Benthic and pelagic sized turtles also exhibited different selectivity ratios for debris ingestion. Benthic phase turtles had a strong selectivity for soft, clear plastic, lending support to the hypothesis that sea turtles ingest debris because it resembles natural prey items such as jellyfish. Pelagic turtles were much less selective in their feeding, though they showed a trend towards selectivity for rubber items such as balloons. Most ingested items were plastic and were positively buoyant. This study highlights the need to address increasing amounts of plastic in the marine environment, and provides evidence for the disproportionate ingestion of balloons by marine turtles.
海洋垃圾是野生动物面临的一个日益严重的问题，据记载，全球有超过 267 个物种因此受到影响。我们调查了 2006 年至 2011 年间在昆士兰州搁浅的 115 只海龟摄入海洋垃圾的情况，并评估了不同物种（玳瑁和绿海龟）和海龟体型大小（较小的海洋食者和较大的底栖食者）之间的摄入率差异。同时，我们进行了 25 次海滩调查，以估计海洋环境中存在的垃圾组成。基于对垃圾存在的这种代理测量，我们使用资源选择函数（一种传统上用于栖息地和食物选择的方法）来模拟海龟对垃圾的偏好（颜色和类型）。我们发现，在所研究的两个物种中，摄入垃圾的总体概率没有显著差异，这两个物种都有相似的生活史。然而，弯曲的甲壳长度与摄入垃圾的概率呈反比；54.5%的远洋型海龟摄入了垃圾，而只有 25%的底栖食性海龟的胃肠道中发现了垃圾。底栖和远洋型海龟对摄入垃圾的选择性比率也不同。底栖阶段的海龟对柔软、透明的塑料具有强烈的选择性，这支持了海龟摄入垃圾是因为它们类似于水母等天然猎物的假设。远洋海龟在进食时选择较少，但它们对橡胶制品（如气球）表现出一种选择性趋势。大多数摄入的物品是塑料，并且具有正浮力。这项研究强调了需要解决海洋环境中不断增加的塑料问题，并为海洋龟类不成比例地摄入气球提供了证据。
