2009 - 2009 Centre for Environment, Fisheries & Aquaculture Science (Cefas) Eastern Irish Sea Razor Clam Survey 2009/10 - Fisheries Science Partnership

The fishing vessel Lord Sam ll was chartered to carry out a survey of razor clam populations on the Cumbrian coast. The aim of the survey was to establish whether a commercially viable stock of razor clam existed in this area. The survey was delayed by inclement weather, but was eventually completed in February 2010. The Seafish/Cefas experimental water-jet dredge was employed north of Walney Island, but there were problems in deploying the gear safely. Those problems added to the sea-time lost through poor weather. In all, 34 dredge deployments were made, but at only 26 of these did the dredge fish successfully. Where the dredge did work well, good catches of the razor clam Ensis siliqua were taken; up to 17 kg in a 10-min haul, although the average catch was ~5kg. The razor clam caught covered a wide size range and young animals from at least two year classes were present, suggesting that successful recruitment is a regular occurrence in the population. The adult population had a modal size pf 185 mm shell length. The highest biomass in by-catches was contributed by the heart urchin Echinocardium cordatum., Several clam species, two possibly with commercial potential, were found regularly.捕捞渔船“萨姆勋爵二世号”（Lord Sam ll）被租用，以开展坎布里亚海岸的竹蛏（razor clam）种群调查。本次调查的目标是确认该区域是否存在具备商业开发价值的竹蛏种群。调查因恶劣天气延误，最终于2010年2月完成。 本次调查在沃尔尼岛以北海域使用了英国海产渔业局（Seafish）/环境渔业与水产养殖科学中心（Cefas）研发的实验性喷水式挖蛤拖捞装置，但在安全布设该设备时遭遇了诸多问题。这些问题进一步加剧了因恶劣天气导致的海上作业时长损耗。本次调查共计完成34次拖捞装置布设作业，但仅其中26次实现了成功捕捞。 当拖捞装置运行正常时，可捕捞到大量长竹蛏（Ensis siliqua）：单次10分钟拖捞的最高渔获量可达17千克，平均渔获量约为5千克。本次采集的竹蛏个体尺寸跨度范围较广，且存在至少两个年龄组的幼体，这表明该种群的成功补充是一种常态现象。成体竹蛏的壳长众数为185毫米。 副渔获物中生物量最高的物种为刺心形海胆（Echinocardium cordatum）。本次调查还定期采集到多种蛤类，其中两种具备潜在商业开发价值。