Abstract：
Pollution and bycatch are two of the main threats for cetaceans worldwide. These threats are exacerbated for nearshore species particularly for those in regions with intense industrial and fishing activities. Burmeister\'s porpoise is endemic to South America, has a Near Threatened conservation status because of long-term mortality in fisheries. Burmeister\'s porpoise occur in Mejillones Bay, northern Chile, a hot spot for heavy metals pollution from the mining industry and an intense industrial and artisanal purse-seine fishing area. From 2018 to 2021, we conducted systematic marine surveys to assess the abundance, distribution and habitat use of Burmeister\'s porpoises. We responded to stranding reports from 2018 to 2022, and necropsied nine individuals. From five of these, we analyzed the metal concentrations (As, Cd, Cr, Cu, Pb, Hg, Se and Zn) in muscle and skin tissues. Results showed an abundance of 76.17 individuals (CV = 25.9%) and an average density of 0.45 individuals/km2 (CV = 26%). Burmeister\'s porpoises were observed year round, 22.2% were mother-calf pairs present in austral summer at an average of 90.6 m depth in the southwestern bound of the bay. Two-thirds of stranded specimens died due to bycatch and one died due to bottlenose dolphin (Tursiops truncatus) attack. We report a dead Burmeister\'s porpoise positive for avian flu virus A (H5N1). Metals analyzed were found in muscle and skin tissues of stranded Burmeister\'s porpoises in the following order (Zn > Cu > Cr > As > Hg > Pb > Cd). Although we could not assess pollution as a cause of mortality, Cr, As and Pb concentrations exceeded the concentrations found in other porpoises species worldwide. We conclude that bycatch and pollution as the main threats for Burmeister\'s porpoise survival in northern Chile. Future studies should investigate the use of acoustic deterrent alarms to mitigate the bycatch in the bay and consider the Burmeister\'s porpoise as a sentinel species of pollution in northern Chilean coast.
摘要：
污染和兼捕是全球鲸类的两个主要威胁。对近岸物种来说，这些威胁更加严重，特别是对工业和渔业活动密集地区的物种。Burmeister的海豚是南美特有的,由于渔业的长期死亡率，其保护状况几乎受到威胁。Burmeister\的海豚发生在Mejillones湾，智利北部,采矿业重金属污染的热点，以及密集的工业和手工围网捕鱼区。从2018年到2021年，我们进行了系统的海洋调查，以评估丰度，Burmeister\的海豚的分布和栖息地利用。我们回应了2018年至2022年的搁浅报告，并对9人进行了尸检。其中五个，我们分析了金属浓度(As，Cd,Cr,Cu,Pb,Hg,肌肉和皮肤组织中的硒和锌）。结果显示，丰度为76.17个个体（CV=25.9％），平均密度为0.45个个体/km2（CV=26％）。全年观察到Burmeister\的海豚，在南端夏季，海湾西南边界的平均深度为90.6m，存在22.2％的母牛对。三分之二的搁浅标本因副渔获而死亡，其中一个因宽吻海豚（Tursiopstruncatus）袭击而死亡。我们报告了一名死亡的Burmeister海豚对禽流感病毒A（H5N1）呈阳性。在搁浅的Burmeister海豚的肌肉和皮肤组织中发现了金属，顺序为（Zn>Cu>Cr>As>Hg>Pb>Cd）。尽管我们无法评估污染是导致死亡的原因，Cr,As和Pb的浓度超过了全球其他海豚物种中的浓度。我们得出的结论是，兼捕和污染是智利北部Burmeister海豚生存的主要威胁。未来的研究应研究使用声威慑警报来减轻海湾中的副渔获物，并将Burmeister的海豚视为智利北部海岸的前哨污染物种。
