A proposed Marine Protected Area (MPA) off Scotland’s west coast would help basking sharks, researchers say.
Scientists from the University of Exeter and Scottish Natural Heritage (SNH) satellite tracked 36 basking sharks in summer months of 2012-2014 and found 86% showed “some degree of residency” in the proposed Sea of the Hebrides MPA.
Sharks also returned year after year, and the scientists believe the area provides conditions for key activities such as foraging and possibly breeding, making it an area important for essential parts of the shark’s life cycle for which MPAs can be designated.
Dr Suzanne Henderson, managing the project for SNH, said: “We have known for some time that basking sharks are frequently seen in Scottish waters during the summer, and they are big attraction for visitors to our west coast.
“But this research shows for the first time that some individuals return to the Sea of the Hebrides in consecutive years, emphasising the importance of the area for sharks.”
Scottish government ministers are currently considering proposals for an MPA in the Sea of the Hebrides, from Skye to Mull, to protect the basking sharks – which are officially endangered in the north-east Atlantic – and minke whales.
“Understanding the conservation potential of an area is key to the successful creation of MPAs,” said lead author Philip Doherty, of the Environment and Sustainability Institute on the University of Exeter’s Penryn Campus in Cornwall.
“It is important to gather data to ensure the evidence-base that underpins the design of MPAs is robust. The data from this project, along-with information gathered over many years by boat-based surveys and from public reports helps to demonstrate the importance of this region for this species”.
An MPA would give additional protection to habitats that are key for basking sharks and ensure their activities within these areas are not disrupted.
Basking sharks, the world’s second-largest fish species, are seen annually in the proposed MPA in the summer, but there had been no detailed study of their movements.
Using data from 36 satellite tags attached to sharks, the Exeter researchers found they spent much of their summer time inside its proposed boundaries.
In winter, some of the sharks stay in UK and Irish waters while others swim south to the waters off France, Spain, Portugal and North Africa.
“The results show us that, with appropriate management, designating this area as an MPA could protect these sharks during the summer months,” said senior author Dr Matthew Witt, also of the University of Exeter.
“These sharks migrate over large distances, so using MPAs to protect them throughout their range is problematic; however, we can protect them in locations where they spend extended periods of time.”
MPAs are parts of the sea where wildlife and habitats are protected by law, with management on activities such as fishing where they are needed. These management approaches, coupled with voluntary measures, awareness raising and enforcement, are crucial to an MPA being successful.
A network of MPAs already exists in the waters around Scotland.
The paper, published in the journal Biological Conservation, is entitled: “Testing the boundaries: Seasonal residency and inter-annual site fidelity of basking sharks in a proposed marine protected area.”