Reason for falloff in sea turtle sightings around UK and Irish coasts unclear, say scientists - The Guardian

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Sightings of sea turtles around the coasts of the UK and Ireland are showing signs of decline, scientists say, although it is unclear what is behind the drop.

Researchers say an analysis of a multi-agency database has revealed that between 1910 and 2018 there were 1,997 records of sightings, strandings or capture of turtles – alive or dead – with 84% relating to leatherback turtles.

Other species recorded included green turtles, Kemp’s ridley turtles and an olive ridley turtle, a small species that favours tropical waters, which was stranded on Anglesey, Wales, in 2016.

While leatherback turtles come to UK waters looking for jellyfish, loggerheads and Kemp’s ridley turtles are transported into the area on currents from the Caribbean or North Atlantic.

However, the team behind the study say the records show concerning trends. Among their findings, they say reports of leatherback turtles increased over the decades to a peak in the 1990s, but since then records appear to have gradually declined.

While there were 553 instances in the 1990s, there were 464 in the 2000s and 256 since 2010 – although the data for the most recent decade is not yet complete.

The team suggest the uptick in earlier decades could be down to a true rise in turtle numbers, greater awareness of reporting schemes, warmer waters or even an increase in prey. Likewise, Zara Botterell, lead author of the study from the University of Exeter, said the apparent decline could be down to many different factors.

“It could be climate change [or] prey availability, but it could also be reporting,” she said, noting there has been a decrease in the number of fishing boats operating in the UK – a key source for turtle sightings.

The study, published in the Journal of the Marine Biological Association of the United Kingdom, also reveals records of Kemp’s ridley turtles have increased since the 1980s, although they, too, have seen a recent decline, albeit only in the past couple of years.

The team say the uptick for this species could be a result of conservation efforts in the US and Mexico to protect turtle nests and prevent nesting females being caught in shrimp nets. Their subsequent drop in numbers, they add, might be linked to the Deepwater horizon oil spill in the Gulf of Mexico in 2010 – a core part of the turtles’ range – among other factors, including a decline in observers.

The Link Lonk


October 19, 2020 at 06:01AM
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Reason for falloff in sea turtle sightings around UK and Irish coasts unclear, say scientists - The Guardian

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