Survey of 20 years of Cetacean strandings around Britain

26 Common dolphins stranded in Cornwall in 2008. Photo credit Rory Goodall/Elemental Tours

9500 whales and dolphins have stranded in the last 20 years
November 2010. Scientists have collated more than 9,000 records as part of one of the largest investigations into marine mammal strandings in Europe.

More than 2,500 post-mortems have been carried out by researchers during 20 years of the Defra-funded UK Cetacean Stranding Investigation Programme (CSIP) coordinated by the Zoological Society of London (ZSL).

Pollution, bycatch, infection and fratricide
The CSIP has produced one of the biggest open access scientific datasets, which includes some of the first evidence of dolphin deaths in fishing nets, links between chemical pollutants and deaths due to infectious diseases, bottlenose dolphins killing harbour porpoises and the discovery of "decompression sickness" in deep-diving whales.

Rob Deaville, CSIP coordinator from ZSL, says "Reports from the public play a crucial role in making us aware of stranded animals. These reports can sometimes prove to be life-saving, but ultimately they all make a valuable contribution to the long-term conservation of cetaceans.

Thames whale
The Thames whale in 2006 and the mass stranding of common dolphins in Cornwall in 2008 are just two of the high profile cases that the CSIP have investigated during the 20 years that the programme has run. 

This map illustrates the number of different  species recorded stranding. Unsurprisingly the Hebrides and Cornwall get the most variety.

Dr Paul Jepson, wildlife veterinarian at ZSL, says "We have studied a huge spectrum of species that has allowed us to build up a picture of how human activities impact our marine life. This had led to changes in policy and best practice around fishing activities, chemical pollutants and military operations. We now need to continue this research to ensure we minimise these impacts in the future."

Turtles and sharks now included
In addition to cetaceans, the species studied by the CSIP have now been expanded to incorporate stranded marine turtles and basking sharks.

Richard Benyon, Minister for Environment and Fisheries, says "This project has done much to improve our understanding of why whales, dolphins and porpoises strand on UK coasts. It is an excellent example of how Government, scientists and conservation groups can work together with dedicated volunteer groups to monitor and protect our wildlife."

Cuvier's & Sowerby's Beaked whales and Sei whales amongst unusual species

Common porpoise and Common dolphins were the most common stranders, but there were some surprising and unusual species too, including Cuvier's and Sowerby's Beaked whales and Sei whales, as well as Pygmy sperm whales.