Conservation Alarm: Basking Shark Sightings Plummet Off Scottish Coast

A recent viral video captured by a kayaker featuring a basking shark off the coast of Scotland has once again focused public attention on the critical need for responsible marine stewardship and strict adherence to conservation regulations. Basking sharks, recognized as the second-largest fish globally, surpassed only by whale sharks, are peaceful planktivores. These gentle giants rarely display aggression toward humans, yet they command respect, reaching lengths of up to 10 meters and filtering microscopic zooplankton through massive mouths that can open a meter wide.

Despite enjoying protected status across the United Kingdom and Ireland, the population of basking sharks in the Northeast Atlantic continues to face significant pressure from anthropogenic factors. Historically, rampant overfishing severely depleted their numbers. Today, modern threats include habitat degradation and the perilous risk of accidental entanglement in fishing gear, known as bycatch. The Hebridean Whale and Dolphin Trust (HWDT), which conducts monitoring activities aboard its research vessel, the “Silurian,” has documented a deeply concerning trend in recent years.

A report published by NatureScot highlighted the alarming statistics. During the entirety of 2023, only seven individual basking sharks were recorded off the Scottish coastline. This figure represents the lowest sighting total documented in the last two decades. For context, the peak observation year occurred in 2010, when HWDT successfully recorded 162 individuals. This dramatic decline underscores the vulnerability of the species.

Experts are currently grappling with the reasons behind this sharp drop. Rona Sinclair of NatureScot suggested that the reduced number of documented sharks might be linked to the availability of their primary food source, zooplankton, or alternatively, the animals may be residing at depths inaccessible to visual observation. Furthermore, HWDT research spanning April 2021 to March 2024 revealed a potential inverse correlation between the frequency of basking shark appearances and minke whales in the Hebrides. When shark sightings were high, minke whale observations tended to decrease, and vice versa. This complex ecological dynamic was highlighted in 2023, which saw a record 167 minke whale sightings, suggesting a shifting ecosystem balance, though the precise causes remain unclear.

Conservation efforts rely heavily on data collection. Organizations like Basking Shark Scotland have actively engaged citizen scientists since 2012, contributing vital data on species distribution and population size in collaboration with Heriot-Watt University. This information is crucial for shaping future conservation policy. Observations typically occur between May and October, peaking in July and August, primarily concentrated within the Marine Protected Area situated between Mull and Skye.

While 2023 was a particularly poor year for sightings, 2024 has offered some tentative signs of hope. For instance, one Basking Shark Scotland tour recorded over 25 sightings in a single day, aligning with expectations for a peak season. This demonstrates that the population is subject to significant fluctuations influenced by environmental conditions, such as the warming of the Atlantic waters affecting plankton distribution. However, concerns persist following the stranding of an immature individual in November 2025 at Portgordon, Moray. Shark and Skate Scotland performed a necropsy to determine the cause of death; while no obvious reason was established, a small fragment of plastic was discovered in the shark’s stomach.