Mass balloon releases can be lethal to animals and should be banned, a marine conservation charity said today.
Balloon releases have long been popular with charities or to remember people who have died or gone missing.
But the Marine Conservation Agency (MCA) says dolphins, whales, seabirds and turtles have died from balloons and wants a national ban on such mass releases.
It says the number of balloons found on UK beaches has more than tripled in the last 12 years, from 3.4 balloons per kilometre to 11.5 balloons per kilometre.
Launching its Don't Let Go campaign, MCA spokesman Gill Bell said: "Marine wildlife is suffering from a range of threats and most people do not give a thought to what happens to their balloons after they are released.
"MCS has evidence of the potentially lethal effects of balloons on animals. Marine animals suffer from a range of threats - please don't let your balloon release be the cause of any more deaths.
"A balloon release is not a cause for celebration, but a possible death sentence for an animal.
"While most balloons used in releases are made of latex rubber, which will eventually biodegrade, many animals may eat the balloons, or become entangled in a balloon's ribbon."
The MCA says mass balloon releases have already been banned by authorities around the world, including some UK bodies.
It gives examples such as a juvenile green turtle washed up at Knott End-on-Sea beach near Blackpool in December 2001, which starved to death after a balloon blocked its gut.