Western English Channel offshore scallop surveys (1981-1996)

Cruises in 1981-1982 with RV Corella were wide ranging dredge surveys of the whole western Channel while those of 1984-1985, using the chartered FV Harm Johannes, concentrated on the grounds between Plymouth and the Lizard out to 12 miles. Since 1990 annual surveys from RV Corystes in July-August have worked 32 of the stations set up in 1984, and since 1993 survey areas south of the Eddystone (25 stations) and in Lyme Bay (20 stations) have been added. Size and age frequency distributions are available for all stations. Some maturity data have also been collected. Underwater CCTV pictures from the survey areas from 1990-1993 are available on video tape, as are a large number of still photographs. ROXANN has been run throughout the survey since 1992 when the system was ground-truthed using a Day Grab. The 1990 and 1991 cruises included an exercise to compare the dredging performance of RV Corystes with commercial vessels. Samples of scallops for growth studies have been collected over a wide area of the Channel and Western Approaches to a depth of 175m.

在1981-1982年间，由RV Corella执行的巡航调查范围广泛，对整个西海峡进行了全面的水下疏浚勘探；而1984-1985年间，租用的FV Harm Johannes则专注于普利茅斯至利泽德之间12海里范围内的海域。自1990年起，RV Corystes在7月至8月进行的年度调查对1984年设立的32个站点进行了研究。自1993年起，在埃迪斯顿以南（25个站点）和莱姆湾（20个站点）增设了调查区域。所有站点的体型和年龄频率分布数据均可用。此外，还收集了一些成熟度数据。1990-1993年调查区域的水下CCTV图像和大量静态照片均保存在录像带上。自1992年起，ROXANN系统在整个调查过程中投入使用，该系统自那时起便通过使用Day Grab进行地面验证。1990年和1991年的巡航还包括了一项实验，旨在比较RV Corystes与商业船只的疏浚性能。在海峡和西航道广阔区域内，对至175米深度的扇贝样本进行了收集，以供生长研究之用。