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More than 800 sightings of whales, dolphins and seals have been recorded in British waters this year.
One project saw whales, dolphins and porpoises spotted off the Yorkshire coast, conservationists said.
And 728 gray seals including seven pups were recorded in Cumbria, a 90% rise from last year.
The organization is a combination of 90 wildlife trusts around the country, each of which are charities run by members and volunteers.
The Yorkshire project saw trained citizen scientists recording hundreds of individual sightings.
Photographs captured a pod of bottlenose dolphins traveling from Scotland to Flamborough Head in East Yorkshire, the furthest south they had been announced identified.
Bex Lynam, North Sea Wildlife Trusts’ marine advocacy officer, said: “It’s likely the bottlenose dolphins came south following shoals of fish; it’s thrilling to see playful dolphins and ocean giants like whales.
“Ten years ago, seeing a bottlenose dolphin off the Yorkshire coast would have been rare.
“We need to collect more data about how and why they are using these waters if we are to better protect them.”
Researchers also logged minke whales feeding off Staithes, in North Yorkshire.
Cumbria Wildlife Trust said it had reported more gray seals at South Walney nature reserve than ever before. Last year it had recorded 483.
A seal was also discovered commuting between the Isle of Man and Cornwall, revealing for the first time how far seals would travel for food and a place to have pups.
Photographs sent by the Manx Wildlife Trust to the Cornwall Seal Group revealed the animal, nicknamed Tulip Belle, has been a regular visitor to the South West since 2001, returning to the Calf of Man to have pups every couple of years.
Joan Edwards, The Wildlife Trusts’ director of living seas, said “more people than ever” were volunteering to help the coast, amid growing concern over wildlife, climate change and pollution.
But the trusts said wildlife was “essential being disturbed by people “including people on personal watercraft frightening dolphins and kayakers scaring seals.
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