Climate change is a threat to dolphins' survival
气候变化威胁海豚生存
Researchers from UZH have now investigated how this environmental damage has affected survival and reproduction of dolphins. They used long-term data on hundreds of animals collected over a ten-year period from 2007 to 2017. Their analyses revealed that the dolphins' survival rate had fallen by 12 percent following the heatwave of 2011. Moreover, female dolphins were giving birth to fewer calves -- a phenomenon that lasted at least until 2017.
基于2007-2017为期十年所收集的数百只动物的长期数据，苏黎世大学研究人员针对“环境破坏是如何影响海豚繁衍生息”展开调查。分析表明，自2011年热浪以来，海豚存活率下降了12％。此外，雌性海豚繁殖量也为之减低。至少到2017年之前，这种现象都未有改观。
"The extent of the negative influence of the heatwave surprised us," says Sonja Wild, former PhD candidate at the University of Leeds and first author of the study. "It is particularly unusual that the reproductive success of females appears to have not returned to normal levels, even after six years." There are several possible explanations for this phenomenon, for instance neglect of calves, increased newborn mortality, delayed sexual maturity, but researchers have not yet been able to investigate them in detail.
该研究第一作者、利兹大学前博士候选人索尼娅·维尔德（Sonja Wild）表示，“热浪的负面影响程度令我们感到惊讶。极为罕见的是，即便在六年之后，雌性的繁殖成功率似乎也没有恢复到正常水平。” 造成这种现象或许有几种解释，例如年幼海豚缺乏照顾、新生海豚死亡率增加、性发育延迟，研究人员尚未能对细节展开调查。
Interestingly, the heatwave did not have the same effect on all dolphin groups. Dolphins that use sponges as tools -- a socially learned foraging technique that helps dolphins to locate food in deep water -- were not as badly affected as those that do not use this technique. "Nevertheless, our work raises concerns that such sudden events might have quite negative long-term effects even in groups of marine mammals that are known to adapt usually well to novel environmental conditions," says Sonja Wild.
有趣的是，热浪对海豚种群造成的影响不尽相同。相较于会把海绵当辅助工具进行深海食物定位的海豚来说，那些不会这种后天习得觅食技能的海豚所遭受的影响更为严重。索尼娅·维尔德说，“不管怎样，我们的工作还是引发了人们的担忧，即使有些已知的海洋哺乳动物种群，它们通常对于新环境条件有不错适应力，也可能受到此类突发事件相当长期负面的影响”。
The UZH researchers show in their study for the first time that marine heatwaves not only affect organisms at lower levels of the food chain, but also might have considerable long-term consequences for the animals at the top, such as dolphins. "Marine heatwaves are likely to occur more frequently in the future due to climate change," says study leader Michael Krützen, professor at the Department of Anthropology at UZH. "This is worrying not only for the long-term prospects of marine mammal populations, but also for the entire oceanic ecosystems."
苏黎世大学研究人员在研究中首次透露，海洋热浪不仅会影响低级食物链有机物，对海豚之类的顶级食物链动物来说，也可能产生极为长期的后果。该研究负责人苏黎世大学人类学系教授迈克尔·克鲁申（Michael Krützen）表示，“由于气候变化，未来海洋热浪出现频率或许更强。届时，不仅海洋哺乳动物种群的长期前景堪忧，整个海洋生态系统也不容乐观。
译者：巴别伦塔
