Scubaism

Dolphins, seals and porpoises could soon become a far more common sight along the Thames, scientists said today. More than 100 of the sea mammals have been spotted in the river over the last year. Researchers say numbers could greatly increase in coming years as the creatures begin to feed in the river more often because of an increased number of fish.

The figures come from the Zoological Society of London’s marine mammal sightings survey. It found that bottlenose dolphins, common and grey seals and harbour porpoises were a common sight between Richmond and the estuary at Southend.

Dr Renata Kowalik, from the society, said: “We have anecdotal evidence that numbers are increasing, although this is only our second year of data so it is hard to predict a trend. We are seeing a lot of seals in Docklands, and we believe the increased number of fish mean they are feeding in the river now.”

Dolphins have moved further up the Thames, with one sighting between Westminster Bridge and Tower Bridge. However, the survey also indicates that sea mammals which make their way as far as Tower Bridge may find themselves in a precarious situation.

Several dead harbour porpoises have been reported shortly after live sightings, and have suffered injuries consistent with boat and propeller collisions. Dr Kowalik said: “Some areas of the river can be very dangerous for these animals, so we need to monitor exactly where they are.

“We are going to be working with several studies in other parts of the UK to see if the increases we see are mirrored elsewhere. We would urge members of the public to take part - we need all the sightings we can get.”