The Zoological Society of London has announced the results of a survey they have carried out into wildlife in the River Thames, it was reported in the Telegraph. The survey, which utilised reports of sightings by members of the public, recorded more than 100 marine mammals in the tidal part of the River Thames (between Richmond and Southend) during the past year, which they believe to be an increase. It will be hard to see a trend until further years have been recorded for comparison – this year is only the second.
It is believed that increase is due to the clean-up of the River Thames from its nadir of pollution in the 1960s to such a clean state today that it supports large numbers of fish species for the mammals to feed on. It is important to have records of the numbers of large marine mammals using the waters so as to avoid collisions between animals and boats which could be detrimental to both, and to try to avoid incidents in which whales and very large animals become stranded further up the river. Seals are now a common sight in Docklands and dolphins are being sighted as far up the river as Tower Bridge.