Sydney, Dec 9 (IANS): 'Begging' dolphins that interacted with humans for food are at greater risk of getting entangled in nets or hit by boats than other dolphins, says a study.

Feeding dolphins is illegal and a key conservation issue.

The Coastal and Estuarine Dolphin Project (CEDP), in an earlier study in 2008, reported that a group of dolphins resident in Cockburn Sound exhibited behaviours indicative of being conditioned to human interaction by food reinforcement (approaching and remaining close to the research boat).

In the current winter 2012 season, adult male Backpack, not previously known as a beggar, has approached the research boat on three different occasions, according to a CEDP statement.

Backpack is an old male (first seen in 1993), resident in Cockburn Sound and recently observed up to Freshwater Bay in the Swan Canning Riverpark.

He mainly associates with Fingers, another old male (first seen in 1993) who has also shown similar 'begging' behaviour.

The Coastal and Estuarine Dolphin Project (CEDP) collects photo-identification, behavioural, and longitudinal data to support the long-term conservation of bottlenose dolphins in metropolitan waters of Perth, Western Australia.