ORCA Poole-Cherbourg surveys

A team of up to four trained volunteers including at least one highly experienced observer recorded cetacean sightings using line transect distance sampling methods from a ferry crossing the English Channel between Poole, UK and Cherbourg, France. Two observers searched a 100° area from either side of the ship with a 10° overlap on the trackline to satisfy the assumption that all animals on the trackline are detected while one observer recorded data and the other rested. Effort information including location, vessel speed, course of vessel and environmental conditions (sea state, swell, precipitation, glare and visibility) were recorded every 30 minutes when observers rotated or when conditions changed. Glare was originally recorded as the position of the glare relative to the ship.由至多4名经过专业培训的志愿者组成的观测团队（其中至少配备1名经验丰富的观测者），采用线样带距离抽样法（line transect distance sampling），在往返英国普尔与法国瑟堡之间、横渡英吉利海峡的渡轮上开展鲸类（cetacean）目击记录工作。两名观测者分别对船舶两侧各100°的视野区域实施搜索，并在观测航线（trackline）上设置10°的重叠覆盖范围，以满足"观测航线上的所有动物均可被侦测到"的假设；观测期间由一名观测者负责记录数据，另一名轮换休息。每间隔30分钟，或在观测者轮换、观测环境发生变化时，记录调查工作量（effort）信息，该信息涵盖观测位置、船舶航速、船舶航向以及环境条件（海况、涌浪、降水、眩光（glare）与能见度）。眩光最初以其相对于船舶的方位进行记录。