The first basking shark sighting of the season has been recorded in Manx waters, according to the Manx Basking Shark Watch (MBSW).
Four adult sharks were spotted in Castletown Bay by a local fisherman on the 24 April.
Jackie Hall, a leading marine scientist in the area, said it is "great to see them return so early in the season."
The sharks are the second largest fish in the world and feed on plankton and normally visit in the summer months.
Anyone who sees a shark off the island's coast over the next few months can report the sighting to the Manx Basking Shark Watch.
So far the MBSW has collected eight years of data on the species but Mrs Hall said that 10 years was needed for a "complete data set".
'Sharks are native'
Mrs Hall said: "Our data suggests that these sharks are native and never actually leave the Manx waters, the Irish sea and the Celtic sea. They simply don't come to the surface a lot."
"Sightings do not usually begin until May but the warm weather is likely to have attracted the shark to the surface," she added.
In 2011, basking shark sightings in Manx waters were the lowest recorded since the MBSW was established in 2005 with 293 sightings, compared with 410 in 2010 and 877 in 2009.
The MBSW is currently working through data from a year-long tagging project, to explore winter movement patterns.
Basking sharks are protected from being hunted or harassed in the Isle of Man and in many parts of the world.