Species point records from 1990 MNCR Loch Tarbert (Jura) survey

Loch Tarbert deeply bisects the south Hebridean island of Jura. It is a relatively small and shallow fiordic loch, some 11 km in length and 43 m at its deepest point. The loch is divided into three basins by the shallow narrows of Cumhann Mor and Cumhann Beag, the latter a very long and tortuous channel. The outer basin, subject to Atlantic swells and exposured to wave action, contrasts with the extremely sheltered and brackish inner basin. There are only weak tidal currents throughout much of the loch, but much stronger currents run through each of the narrows. Despite its proximity to mainland Scotland, and in contrast to most other Scottish lochs, Loch Tarbert is almost completely undeveloped. Only two houses lie beside its shores and the surrounding mountainous land is almost entirely given over to Jura's extensive population of deer. At present there is little mariculture or fishing activity within the loch. The loch was previously surveyed by Smith (1982) and Hiscock (1983) for the Nature Conservancy Council. The present survey, in 1990, complements these earlier surveys and contributes to the MNCR Survey of Scottish sealochs, which is being undertaken jointly by the MNCR and the University Marine Biological Station, Millport. The results from all three surveys have been incorporated here. In all nine shore sites and 19 sublittoral sites have been surveyed, From the data four littoral and 12 sublittoral habitat/community types are described, and 516 taxa listed. The shores were predominantly rocky and covered by fucoid algae. Within the two narrows enhanced currents yielded rich lower shore communities of sponges, hydroids and ascidians. The more exposed shores in the outer basin were not examined. The sediment shores supported populations of the lugworm Arenicola marina and the cockle Cerastoderma edule. Some extremely sheltered embayments had patches of the eelgrass Zostera nana and the unattached knotted wrack Ascophyllum nodosum ecad mackaii. In the sublittoral the sheltered middle basin had a narrow band of the kelp Laminaria saccharina which gave way to muddy plains at 2-3 m with populations of the seapen Virgularia mirabilis and the opisthobranch mollusc Philine aperta. In the outer loch rocky habitats extended to 5-12 m depth and supported a Laminaria hyperborea kelp forest, with L. saccharina on more unstable rocks. Below this sediment plains again supported populations of Virgularia mirabilis, but were accompanied here by the bivalve Arctica islandica, the heart urchin Echinocardium cordatum and the brittlestar Amphiura brachiata. Shallow sediments were covered by mats of filamentous algae. In the narrows there was a mixture of tideswept rock with L. hyperborea and Halidrys siliquosa and coarse gravels with sparse maerl, burrowing anemones and the sea cucumber Neopentadactyla mixta. For its size Loch Tarbert is subject to a particularly wide range of wave exposures, tidal currents and salinity. Habitat diversity within the loch is moderately high and species richness is high. Five of the habitat/community types and two species have been rated of conservation importance. The Cumhann Beag narrows is considered the most biologically interesting part of the loch and its shores are recommended for designation as a Site of Special Scientific Interest. Records currently considered sensitive have been removed from this dataset.

洛赫·塔伯特深嵌于赫布里底群岛南部的朱拉岛上。此湖泊为一相对较小的浅水峡湾，全长约11公里，最深处达43米。湖泊被库姆汉·莫尔和库姆汉·贝格的浅窄海峡分为三个盆地，其中后者是一条漫长而曲折的航道。外盆地受大西洋涌浪影响，暴露于波浪作用之下，与极端隐蔽且咸淡交错的内盆地形成鲜明对比。整个湖泊大部分地区的潮汐流速微弱，但通过每个海峡的流速则相对较强。尽管洛赫·塔伯特紧邻苏格兰大陆，与其他多数苏格兰湖泊相比，它几乎未得到开发。湖岸旁仅有两座房屋，周边的山地几乎完全被朱拉岛丰富的鹿群占据。目前，湖泊内几乎没有海洋养殖业或渔业活动。洛赫·塔伯特曾由史密斯（1982年）和希科克（1983年）代表自然保护委员会进行过调查。本次调查于1990年进行，旨在补充先前的调查，并为苏格兰海港的MNCR调查做出贡献，该调查由MNCR和米尔波特大学海洋生物站共同开展。所有三次调查的结果均纳入本报告。调查涵盖了九个岸线地点和十九个海底地点，从数据中描述了四种岸线及十二种海底生境/群落类型，并列出了516个物种。岸线主要以岩石为主，覆盖着苔藓藻。在两个海峡中，增强的流速孕育了丰富的下岸社群，包括海绵、水螅和海鞘。外盆地更暴露的岸线未被考察。沉积岸线支持着沙蚕（Arenicola marina）和文蛤（Cerastoderma edule）的种群。一些极端隐蔽的湾口区域出现了小片的海草（Zostera nana）和无节海藻（Ascophyllum nodosum ecad mackaii）。在海底区域，隐蔽的中部盆地有一狭窄的藻类带，为糖槭藻（Laminaria saccharina），随后过渡至2-3米的泥泞平原，此处有海笔（Virgularia mirabilis）和后鳃亚门软体动物（Philine aperta）的种群。在外部湖泊中，岩石生境延伸至5-12米深度，支持着超极藻（Laminaria hyperborea）森林，在更不稳定的岩石上则是糖槭藻。在这之下，沉积平原再次支持着海笔种群，但此处伴随有双壳类（Arctica islandica）、海胆（Echinocardium cordatum）和海星（Amphiura brachiata）。浅层沉积物被丝状藻类的垫子覆盖。在海峡中，有潮汐冲刷的岩石与超极藻和海索草（Halidrys siliquosa）以及粗砾石和稀疏的珊瑚藻、掘穴水母和海参（Neopentadactyla mixta）的混合。对于其规模而言，洛赫·塔伯特受到特别广泛的波浪暴露、潮汐流速和盐度的制约。湖泊内的生境多样性适中，物种丰富度较高。五种生境/群落类型和两种物种被评定为具有保护价值。库姆汉·贝格海峡被认为是湖泊中生物多样性最为丰富的部分，其岸线被推荐指定为具有特殊科学兴趣的地点。目前被认为敏感的记录已从本数据集中移除。