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.

捕鱼船洛德·萨姆二世被租用以对康沃尔海岸的锯蛤蜊种群进行调查。此次调查的目的是确立该区域是否存在具有商业开采价值的锯蛤蜊种群。调查因恶劣天气而推迟，但最终在2010年2月完成。

在沃利群岛北部使用Seafish/Cefas实验性水射流挖泥船进行作业，但在安全部署设备时遇到了问题。这些问题叠加了因天气不佳而损失的海上作业时间。总计进行了34次挖泥作业，但只有26次挖泥作业成功捕捞。

在挖泥作业表现良好的区域，捕获了大量的锯蛤蜊（Ensis siliqua），每次10分钟的拖网作业可捕获高达17公斤，尽管平均捕获量约为5公斤。捕获的锯蛤蜊覆盖了广泛的大小范围，且至少存在两个年龄层的幼体，这表明成功繁殖是该种群中的一种常态。成年种群的平均壳长为185毫米。

在副产物中，最高生物量由海胆（Echinocardium cordatum）贡献。发现了多种蛤蜊，其中两种可能具有商业潜力，且被定期发现。