Four people have died in three separate kayaking accidents since Tuesday.
A 19-year-old man got trapped under rocks on the River Tay in Scotland and two men drowned in the River Clodagh in Co Waterford, Ireland, yesterday.
Rescuers battled for almost seven hours to save the teenager in Perthshire, but fast-flowing water prevented crews from freeing the trapped kayak.
Fire crews, a Royal Navy helicopter from HMS Gannet and a local rescue boat were called to the scene near Grandtully at around 1.30pm.
Tayside Police said a recovery operation was expected to begin today once the water levels reduced.
A slalom canoe event due to be held on the river has been cancelled as a mark of respect to the friends and family of the man, who is understood to be from the Cleveland area.
Meanwhile, the community of Portlaw, Co Waterford, was in shock after the deaths of two men last night.
The kayakers got into difficulty on the River Clodagh at around 9pm and local rescue teams recovered the first kayaker's body about an hour later.
The second man's body was taken from the water at around 11.30pm.
It is understood the pair drowned after getting trapped in a weir of the river - a tributary of the River Suir.
The bodies were taken to Waterford Regional Hospital, where a post-mortem examination was due to take place.
The accidents follow another river death earlier this week.
Emily Parker, 20, from Doncaster, was with a group on the River Coe in Glencoe, Argyll, on Tuesday when her kayak overturned.