Habitat point records from 1982 Dipper Wash sublittoral diving/dredging survey

This report notes the importance in the Wash of the sublittoral faunal populations, which may be a source of recruitment to the intertidal areas, for nature conservation and for fisheries. Although some information is available on the sublittoral of the Wash from remote sampling, very little diving has been done in the area due to low visibilities and strong tides. Although most of the area consists of mobile soft sediments, indications of some type of hard substratum are given by the masses of bryozoa and hydroids regularly washed up on the beaches. The aims of this preliminary survey were therefore to establish the feasibility of using diving to carry out a survey in this area, to collect information on the sublittoral, particularly in the Lynn Well area where 'rocky' outcrops were suspected and to make contacts with other organisations and individuals interested in the sublittoral of the Wash. The survey was carried out during a period of neap tides from a trawler owned by the Eastern Sea Fisheries Joint Committee. Two dives and three dredges were made. Descriptions of dive and dredge sites are provided, and species identified listed. No evidence of hard substrata was found, the sediments apparently consisting of muds and sands with a considerable amout of shell and pebble debris. The epifauna in the deeper areas dredged in Lynn Well was found to be fairly rich, with abundant hydroid material, Flustra foliacea and worm tubes attached to stones and shells on the sea bed. The infauna was also thought to be fairly rich, but only the top few inches of sediment could be sampled by dredge. In the Roaring Middle area a harder substratum may be present since little sediment was brought to the surface, and Modiolus beds are thought to occur here. Diving in the Wash is not a very effective method of survey due to the constraints of slack water and low visibility. However, it does provide a better indication of the composition and spatial arrangement of the communities and also allows collection of small organisms and other fragile material; information which may be lost from dredged collections. The report suggests therefore that diving would be a useful tool for backing up remote sampling methods in areas where interesting hauls have come to the surface.

本报告强调了在Wash海域中，海底生物群落的重要性，这些群落可能是向潮间带区域补充种群的重要来源，对于自然保护及渔业均具有重要意义。尽管从远程采样中获取了一些关于Wash海底的信息，但由于能见度低和潮汐强烈，该区域的潜水活动极为有限。尽管该区域大部分由流动的软质沉积物组成，但大量被冲上岸边的苔藓虫和珊瑚群表明，此处存在某种类型的硬质底质。因此，此次初步调查的目的在于验证使用潜水进行该区域调查的可行性，收集关于海底的信息，特别是在疑似存在‘岩石’露头的Lynn Well区域，并与对Wash海底感兴趣的其它组织和个人建立联系。调查是在小潮期间，由东部海洋渔业联合委员会拥有的拖网船上进行的。进行了两次潜水作业和三次疏浚。提供了潜水点和疏浚点的描述，并列出了鉴定出的物种。未发现硬质底质，沉积物显然由泥土和沙子组成，夹杂着大量的贝壳和鹅卵石碎片。在Lynn Well区域疏浚的较深区域，表生生物种类丰富，有大量的珊瑚群材料、Flustra foliacea和附着在海底岩石和贝壳上的蠕虫管。据推测，底栖生物种类也相当丰富，但只能通过疏浚采集到沉积物的最上层几英寸。在Roaring Middle区域，由于携带到表面的沉积物很少，可能存在较硬的底质，并推测此处有Modiolus床。由于潮汐平缓期和低能见度的限制，在Wash海域潜水并不是一种非常有效的调查方法。然而，它确实提供了对群落组成和空间排列的更好指示，并允许收集小型生物和其他脆弱材料；这些信息可能会从疏浚采集物中丢失。因此，报告建议，潜水可以作为远程采样方法的有益补充工具，在出现有趣收获的海域进行使用。