Discovering the Tides Around Torsa Island

Torsa Island from a bird's-eye view

Torsa is not only my name but also a small island on the west coast of Scotland, which grabbed my attention as a heavenly place on earth. The name Torsa, which is believed to have taken its name after Old Norse or literally the Isle of Thor, is a stamp member of an ancient tribal history. The most impressive of its relics is Caisteal nan Con, or the Dogs Castle, a wrecked tower-house (medieval) upon the end of a rocky eminence at the northeast end of the island. In the late Middle Ages, the fortlet was possessed by Clan Campbell, and it acted as a territorial lookout of the sheltered inland waters of Loch Sunart and the access in front.

Torsa Island is located on the east of the long and sheltered sea loch called Loch Sunart, which leads to the Atlantic on the other side through the Firth of Lorn. Due to the fact that the island lies close to Camas Torsa, marine habitats and wildlife identified in Loch Sunart directly can be applied to the Torsa aquatic ecosystem. As of 2014, Torsa forms the portion of the Loch Sunart to the Sound of Jura Marine Protected Area (MPA), a title that encompasses 741 km² and is designated to preserve flame shell reefs, kelp forests, serpulid worm beds, and the critically endangered flapper skate of Scottish Marine. Consequently, the habitats and species within the waters of Torsa are also preserved with the aid of the same surveys, protections, and management measures applied in Loch Sunart.

Especially on the tidal channel edges like Loch Teacuis and Laudale Narrows, there are unusual flame shell beds on the seabed off Torsa. These vibrant orange-colored clams construct overlapping nests, which act as stable surfaces to other organisms, such as up to 19 species of algae and 265 species of invertebrates on each reef; it is also a Priority Marine Feature in Scotland also.

Serpulid worm massing, or reefs of the so-called organ pipe worm, were also occasionally present in the vicinities of such localities as Loch Teacuis. They grew thick in soft sediment regions and in the past covered large acreages, as much as 20 hectares with a 4% reef cover before 2015; however, most have dwindled over the years. The communities of sponges, northern sea fans, brittle stars, feather stars, and sea stars can be found in other hard-bottom areas near Torsa, particularly at deeper rocky nets and trawl-free sites.

Rocky reefs around the island provide a habitat to kelp forests and, in the subtidal areas, tide-swept seaweed meadows. Typically, these kelp beds are close to the flame shell reefs, which in combination improves stability in habitat and promotes further expansion of life. Beds of hard-coated algae and seagrass beds also connect with flame shell habitat in adjacent lochs and, in addition, maintain sediment stability and create a nursery habitat suitable to young sea life.

Serpulid reefs around the Island

Wildlife and marine animals make the waters of Torsa very rich. Shy otters may often be seen hunting out in the kelp and the shallow reefs, especially at Camas Torsa, where little disturbance prevails. Seals can regularly be found reclining on a rocky beach or even in the body of water nearby, perhaps visible to small boats at coastal regions. Harbor porpoises and dolphins are regularly seen in Loch Sunart and in and around Torsa, and basking sharks are occasionally sighted by local guides and boat crew. The flapper skate is also a critically endangered species under the conservation marquee, of which a tracking study has revealed that these skates are site fidelity animals in the sense that they remain at the same locations across the year.

Kelp Forest around the Island

The decades of angler-collected data that began in the 1970s, followed by scientific tagging and photo-ID streams like the Skatespotter database, were a major reason why the MPA was established. In 2019, intensive surveys were carried out that focused on the presence of juvenile skate nursery habitats within the zone of Torsa, and they contained various forms of intense survey, such as demersal trawls, baited remote underwater video, and environmental DNA.

In total, the waters of Torsa Island have a more dynamic seascape, and it is influenced by a combination of high tidal currents, varied seabed, and stringent MPA-related preservation. The prevalence of flame shell and kelp habitats is attributed to the fact that these species flourish in currents of the harsh nature that is enjoyed by this coastline. Citizen science, cautious regulation and monitoring additionally lead to flapper skate being a rare but locally well-known species. The ongoing inter-agency collaboration of researchers, anglers and conservation agencies keeps these lush marine communities whole, and even rebounding with each successive year.