Public urged to take part in Thames marine survey

The Zoological School of London (ZSL) is appealing for volunteers to join the search for dolphins, porpoises and seals in the Thames Estuary as part of the Thames Marine Mammal Sightings Survey.

The ZSL said that while it was known that marine mammals use the Thames, there was a "big gap" in knowledge about the population levels and usage patterns in the area. The survey is designed to help make "valuable contributions" to protecting species in the UK's native waters.

Recent sightings in the River Thames and the Thames Estuary have included bottlenose dolphins, harbour porpoises, common seals and grey seals. Grey seals are among the rarest in the world, the UK population of approximately 124,000 represents about 40% of the world's population. It is estimated that there are just 300 bottlenose dolphins in UK waters and 350,000 harbour porpoises.

The main threats to marine mammals in the UK are thought to be ecosystem change, fisheries by-catch, chemical contamination and boat traffic.

All species of marine mammal are protected from killing, capture and deliberate disturbance in UK waters but without data showing which areas are valuable to these animals it is difficult to enforce these directives, the school said.

Alison Shaw, ZSL Marine & Freshwater Conservation Programme Manager, said: "Assessing the consequences of development activities requires long term monitoring of these animals. To be useful this must be in place before new activities develop. The data ZSL collects on marine mammal movements may prove invaluable in assessing the impact of new operations in the Thames Estuary."

The data also will help address conservation issues by identifying important habitats, exploring why they are important and improve our ability to predict marine mammal distributions at sea, year round.

To take part in the survey volunteers are asked to complete a short questionnaire about their sighting.

(gmcg)