The demise of the young swans caused a great deal of sadness among local people who enjoyed watching and feeding them during walks along the towpath where they had become a common sight, swimming alongside their parents.

The first sign something was amiss came last Tuesday afternoon when one of the cygnets was seen struggling in the water.

Just one of the parent swans was present in an obviously distressed state and regular users of the towpath feared the worst as the little family normally stayed close together.

The body of another cygnet was spotted floating in the water and the scene was visited by Deputy Mayor Alderman Edwin Poots and Councillor Paul Porter.

Both men said it had been sad to see one cygnet struggling just out of reach of help and another already dead.

Local people feared the birds were victims of either poisoning, pollution or vandalism but an Environment and Heritage Service Inspector attended the scene and found 'no signs of pollution'.

However, the following day the department was informed the Royal Society for the Protection of Birds had reported a dead fish and a number of dead ducks downstream of Lambeg. An inspector walked along the towpath from Lambeg downstream as far as Ballyskeagh but observed just one single dead fish in the Lagan Canal and no dead ducks.

An EHS spokesperson continued: "At the time, the Inspector did note the presence of many live birds and chicks on both the river and the canal.

"There were also large numbers of small live fish present which did not show any signs of distress. If there had been a significant pollution impact, then the smaller fish would have been the first to be affected.

"No signs of water pollution impact were observed by the Inspector. However, as a precaution, river samples were taken for analysis around Lambeg. Whilst the results of the analysis remain outstanding, EHS considers that it is most likely the bird deaths were as a result of a natural occurrence rather than as a result of water pollution."

neil.greenlees@jpress.co.uk