A soft-shelled turtle has been seen in Injebreck reservoir, Baldwin.

Terrapins have also been spotted at Scarlett near Castletown and Ballaugh.

It’s feared that there is a growing trend for people to release these probably unwanted and oversized pets into local ponds and waterways.

The Manx Wildlife Trust says this will hit native wildlife and harm the dumped creatures, many of which would not survive an island winter.

A spokesman said: ’Few studies have been completed as to the exact impact released turtles and terrapins can have, but they have no natural predators to control their numbers and as such will become the top of the food chain in a pond.

’They will readily eat any water plants, meaning less for our native species as well as depleting oxygen levels within the ponds.

’They will also consume frogspawn, frogs, invertebrates such as dragonfly larvae and larger specimens may even consume ducklings.

’The terrapins and turtles may carry harmful fungus, even spread Hexamita protozoan to birds and the deadly Ranavirus to frogs.’

He added that it was unlikely in our cooler climate that the turtles and terrapins would breed and, being cold-blooded animals, it would affect their ability to eat and undergo hibernation.

They need enough ultraviolet light to be able to extract calcium from their food to survive.

Without this they can become blind and unable to feed. They are also more likely to succumb to respiratory diseases and hypothermia

The MWT spokesman said: ’Releasing them into the wild is to subject them to a cruel death. We are urging the public to think very carefully about buying a terrapin or turtle for a pet.

’They can live for 25 years and certainly grow to a much larger size than the little coin sized specimen you bought from the pet shop.

People who spot a turtle or terrapin in the wild should tell the Manx Society for the Prevention of Cruelty to Animals so it can be recovered and notify the Manx Wildlife Trust and or the Department of the Environment, Food and Agriculture.