西沙群岛七连屿绿海龟(Chelonia mydas)产卵场海滩垃圾调查

Investigation of beach debris at spawning ground of Green Sea Turtles (Chelonia mydas) at Qilianyu Islands,Northeastern Xisha Islands

产卵场的海滩垃圾是海龟筑巢和孵化的主要威胁之一。西沙群岛七连屿是中国绿海龟(Chelonia mydas)现存最大的产卵场,虽然远离大陆,人口稀少,相对隔绝,但污染依然不容忽视。本研究采用样方法对七连屿绿海龟产卵的6个岛屿进行海滩垃圾调查。结果表明:七连屿绿海龟产卵场的海滩垃圾类型主要有塑料、金属、玻璃等,其中以塑料垃圾最多,数量占比82.04%,质量占比45.98%;海滩垃圾的平均数量密度为0.38个·m^-2,平均质量密度为7.66 g·m^-2;相比其他海龟产卵场,七连屿海滩垃圾的平均数量密度处于较低水平,但塑料垃圾占比较高;海滩垃圾以生活用品类最多,数量占比74.33%,其次为航运/捕鱼活动残留,数量占比9.11%;通过识别塑料垃圾上的文字,调查到的垃圾来源于国外的垃圾占比高达82.02%,以越南、马来西亚等东南亚国家为主,占国外垃圾的96.3%。建议进一步加强七连屿海龟产卵场的海滩垃圾减排和清理,同时加强南海的区域合作,共同促进海洋垃圾的治理。

Beach debris at spawning grounds is a major threat to the nesting and hatching of sea turtle.The Qilianyu Islands,a subgroup of islands in the northeastern part of the Xisha Islands,is the largest spawning ground for green sea turtles(Chelonia mydas)in China.Although this site is far from the mainland and relatively isolated with a small human population,pollution could not be ignored.We surveyed beach debris in and around the spawning ground of C.mydas on six islands of Qilianyu.We found that the beach debris consisted of plastic,metals and glass,with plastic being the dominant type,accounting for 82.07%in number and 45.98%in mass.The average number density of beach debris was 0.38 pieces·m^-2,and the average mass density was7.66 g·m^-2.Compared with other spawning grounds,the average density of beach debris here was lower,but with higher proportion of plastic debris.After categorizing the type of debris,we found that most debris was from household goods(74.33%),followed by that from shipping/fishing activities(9.11%).Based on the words on the plastic debris,we inferred that the geographic source was primarily from abroad(82.02%),mainly from Southeast Asian countries,such as Vietnam and Malaysia,accounting for 96.3%of foreign debris.To better protect this important spawning ground,we recommend strengthening beach debris reduction and cleanup at Qilianyu,with much stronger regional cooperation.