Discovered: The epic journey of a basking shark
by Cheryl-Samantha Owen
Basking shark in UK waters
At this time of year, each year, a dark triangular fin appears off the British Isles. Slicing through the waters off Cornwall, Isle of Man, Southern Ireland and Scotland's Western Isles. It stirs more than the water it swims through, as a rippling wave of fin-phobia takes hold of the British public, ensued by many hours of speculation over what shark lies beneath. That fin, between one and two metres long, belongs to the world's second largest fish, a shark with a body that grows up to 10 metres and a mouth almost as wide as a piano, the basking shark Cetorhinus maximus.
Little is known about this gentle giant, whose humble diet consists of the microscopic organism plankton, and until now it was thought in Europe to migrate north in the spring to England and up to Scotland, before returning south in the autumn. Where exactly south they moved was until now a mystery. Dr Mauvis Gore, a marine biologist with the Save Our Seas Foundation, who has been studying these animals for the past five years has shed new light on their movement patterns. With her discovery comes the realisation that, since this endangered species is not protected outside Europe, it might be more vulnerable than previously thought.
A female basking shark tagged off the Isle of Man travelled 9,589 km to the waters off the Newfoundland shelf, and on her journey across the Atlantic Ocean she reached a maximum depth of 1,264 metres. This is the first conclusive evidence for basking sharks' use of the deep mid-ocean, a record dive depth for tagged sharks, and perhaps more importantly the first evidence that the species migrates across oceans or between hemispheres.
According to Dr Gore, "These results give the first link between the European and American basking shark populations, and what was once thought to be two discrete populations is very likely to be effectively a single one unit."
With basking sharks now traversing from one hemisphere to another, they could be exposed to exploitation in waters where they are not protected.The implications for the species' conservation are significant, especially given that the global population size consists of approximately 8,200 individuals.
"International collaboration with governments and scientists and the protection of basking sharks across all ocean regions is essential if this species is to survive," states Dr Gore.
Story originally published here. Download the press release here.
Little is known about this gentle giant, whose humble diet consists of the microscopic organism plankton, and until now it was thought in Europe to migrate north in the spring to England and up to Scotland, before returning south in the autumn. Where exactly south they moved was until now a mystery. Dr Mauvis Gore, a marine biologist with the Save Our Seas Foundation, who has been studying these animals for the past five years has shed new light on their movement patterns. With her discovery comes the realisation that, since this endangered species is not protected outside Europe, it might be more vulnerable than previously thought.
A female basking shark tagged off the Isle of Man travelled 9,589 km to the waters off the Newfoundland shelf, and on her journey across the Atlantic Ocean she reached a maximum depth of 1,264 metres. This is the first conclusive evidence for basking sharks' use of the deep mid-ocean, a record dive depth for tagged sharks, and perhaps more importantly the first evidence that the species migrates across oceans or between hemispheres.
According to Dr Gore, "These results give the first link between the European and American basking shark populations, and what was once thought to be two discrete populations is very likely to be effectively a single one unit."
With basking sharks now traversing from one hemisphere to another, they could be exposed to exploitation in waters where they are not protected.The implications for the species' conservation are significant, especially given that the global population size consists of approximately 8,200 individuals.
"International collaboration with governments and scientists and the protection of basking sharks across all ocean regions is essential if this species is to survive," states Dr Gore.
Story originally published here. Download the press release here.