CastAway CTD Data: 2017-2019 and 2021, Gulf Watch Alaska Pelagic Component, Long-term Monitoring of Humpback Whale Predation on Pacific Herring in Prince William Sound

These data are part of the Gulf Watch Alaska (GWA) Pelagic component, which is a long-term ecosystem monitoring program of the Exxon Valdez Oil Spill Trustee Council (EVOSTC) for the marine ecosystem affected by the 1989 oil spill. As part of a larger study of humpback whale (Megaptera novaeangliae) impact to Pacific herring (Clupea pallasi) populations in Prince William Sound (PWS), CTD surveys were conducted as part of an integrated fall/winter predator-prey survey. Vessel surveys in Prince William Sound (PWS) were conducted twice per year during the spring and fall months to record Conductivity, Temperature, and Depth (CTD) measurements. The surveys were timed to coincide with the movement of whales into the PWS. The surveys visited PWS bays that have historically been used by whales and herring to maintain ongoing EVOSTC funded long term monitoring surveys for humpback whales. The dataset is presented as .zip file containing collections of CSV files by study year from 2017-2019 and 2021 for different survey locations. A field season in 2020 was cancelled due to the COVID-19 pandemic. The individual CTD files are named: __< Cast time in UTC > location . The files contain pressure, depth, temperature, conductivity, conductance, salinity, sound velocity, and density for each CTD cast. Instrument metadata is contained in the header file.

本数据集隶属于阿拉斯加海湾观察（Gulf Watch Alaska, GWA）远洋带组分，该项目是埃克森瓦尔迪兹溢油赔偿托管委员会（Exxon Valdez Oil Spill Trustee Council, EVOSTC）针对1989年溢油影响海域开展的长期海洋生态系统监测计划的组成部分。作为针对威廉王子湾（Prince William Sound, PWS）内座头鲸（*Megaptera novaeangliae*）对太平洋鲱（*Clupea pallasi*）种群影响的大型研究的一部分，电导率-温度-深度（Conductivity, Temperature, and Depth, CTD）调查被纳入秋冬整合捕食者-猎物调查体系。研究团队每年春秋两季在威廉王子湾开展船舶调查，以记录CTD测量数据。调查时段与座头鲸洄游进入该海湾的时间相契合，调查站点选定在历史上座头鲸与太平洋鲱的典型栖息海湾，以持续推进由EVOSTC资助的座头鲸长期监测工作。本数据集以.zip压缩包形式提供，内含2017-2019年及2021年各研究年份下不同调查站点的逗号分隔值（Comma-Separated Values, CSV）文件集合。2020年的野外调查季因新冠疫情（COVID-19 pandemic）被迫取消。单条CTD数据文件的命名格式为：__< UTC时间的CTD投弃时刻 > <调查站点名称>。每份文件包含单次CTD投弃的压力、深度、温度、电导率、比电导、盐度、声速及密度数据，仪器元数据存储于文件头中。