Whale sightings during POLARSTERN cruise PS134

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 PS134 (Cape Town – Punta Arenas) 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.

极地海洋中鲸类的分布与种群丰度相关数据相当匮乏，原因在于标准调查方法——线样带调查（line-transect surveys）的实施难度高且成本高昂。为解决这一难题，我们启动了一项计划，通过当班航海官员记录所有Polarstern（极星号）科考航次中偶遇鲸类的观测数据，并以电子形式存档。在Polarstern第PS134航次（开普敦—蓬塔阿雷纳斯航线）期间，当班航海官员借助安装在船舶驾驶台触摸屏笔记本电脑上的定制化软件包WALOG（WhAleLOGger，鲸类观测记录仪），记录了裸眼目视的偶遇鲸类观测数据。观测人员通过裸眼或手持双筒望远镜（7×50规格），尽可能将物种鉴定至最低的分类学层级，并为其赋予鉴定置信度等级。若可行，将统计动物个体数量；对于较大种群群，则进行数量估算。若无法鉴定至物种层级，则将其归类至可识别的次一级分类学类别。观测位置、日期与时间等信息，会在记录时自动从船舶DAVIS-Ship系统（https://dship.awi.de/）同步至WALOG软件。如有条件，将拍摄照片以供回溯分析使用。所有收集到的观测数据，均由海洋生物学家进行回溯验证，并转换为标准格式。为此，我们将核查观测时间与位置的合理性、物种名称的标准化处理、观测时添加的备注信息，以及照片（如有）等补充信息，以验证或优化物种鉴定结果。本数据集可应用于物种分布建模，并可向相关方通报鲸类观测记录的发生情况。