Whale sightings during POLARSTERN cruise PS113 (ANT-XXXIII/4)

Data on whale distribution and abundance in the polar oceans is rather sparse, as implementing the standard surveying method, line-transect surveys, is challenging and costly. To overcome this problem, we initiated a program to electronically log all opportunistic cetacean sightings during all Polarstern expeditions through the nautical officer on watch. Opportunistic (visual) sightings by naked eye were logged during Polarstern Cruise PS113 (Punta Arenas - Bremerhaven) by the nautical officer on duty using a customized Software package (WALOG, WhAleLOGger) installed on a touch screen laptop located on the ship's bridge. Species were identified by naked eye or handheld binoculars (7x50) to the lowest possible taxonomical level and assigned a "certainty" level of identification. The number of animals were counted if possible or estimated for larger groups. Whenever identification to species level was not possible, the next identifiable taxonomical category was assigned. Information on sighting position, date and time are automatically transferred from the ship's DAVIS-Ship System (https://dship.awi.de/) to the WALOG software at the time of logging. Photographs were taken if possible for retrospective analysis. All data of acquired sightings were retrospectively validated by a marine biologist and converted to a standard format. To this end, plausibility of sighting time, location, standardization of species names, eventual comments added at the time of sighting, as well as additional information such as photographs (if available) were checked either to verify or improve species identification. Datasets are used in species distribution modelling and to inform interested parties about occurrences.

极地海洋中鲸鱼分布与丰度的数据较为稀疏，因为实施标准调查方法——线样带调查（line-transect surveys）——具有挑战性且成本高昂。为解决这一问题，我们启动了一项计划，通过值班航海官在极星号（Polarstern）所有考察期间以电子方式记录所有机会性鲸类目击事件。在极星号航次PS113（蓬塔阿雷纳斯—不来梅港）期间，值班航海官通过安装在舰桥触摸屏笔记本电脑上的定制软件包（WALOG，WhAleLOGger）记录了肉眼观察到的机会性（视觉）目击事件。物种通过肉眼或手持双筒望远镜（7×50）识别至尽可能低的分类学级别，并被赋予‘确定性’识别等级。尽可能对个体数量进行计数，对于较大群体则进行估算。若无法识别至物种级别，则采用下一个可识别的分类学类别。目击位置、日期和时间信息在记录时会自动从船舶的DAVIS-Ship系统（https://dship.awi.de/）传输至WALOG软件。尽可能拍摄照片用于回顾性分析。所有获取的目击数据均由海洋生物学家进行回顾性验证，并转换为标准格式。为此，检查了目击时间的合理性、位置、物种名称的标准化、目击时添加的最终注释以及照片等附加信息（若有），以验证或改进物种识别结果。