Over 100 people recently attended the Cornwall Wildlife Trust Marine Strandings Network (MSN) Forum, the highest number of participants seen at this annual event. The symposium was hosted by Truro College and the Network’s volunteer team were joined by invited guests from a wide range of research and educational organisations.

Delegates enjoyed lectures from invited speakers working at the forefront of marine mammal research. Dr Ailsa Hall, Deputy Director of the Sea Mammal Research Unit, spoke on the breeding and survival of the grey seal. The MSN has recently received some funding for the post-mortem examination of stranded seals and hopes to learn a great deal more about the causes of mortality among this species locally.

James Barnett, Veterinary Investigation Officer at the Veterinary Laboratories Agency (VLA) in Truro, spoke about the role that pathology plays in helping to make decisions when dealing with live-stranded cetaceans, particularly whales. Of 138 live strandings attended by the charity British Divers Marine Life Rescue (BDMLR), 46 were euthanased. He went on to explain that in only one case did the post-mortem examination not support the decision to euthanase, with the remainder being malnourished, maternally dependent, suffering from severe trauma, disease or strandings related pathology.

Over the last 20 years, volunteers have gathered strandings data in Cornwall, which has been contributed to the Defra-funded, UK-wide, Cetacean Strandings Investigation Programme (CSIP). Rob Deaville, manager of the scheme, presented the analysis of the data. 9494 cetaceans of 20 different species were recorded over the 20 year period. 2774 animals were examined by pathologists and accidental capture in fishing nets was found to be the main cause of death, followed by infectious disease.

2960 cetaceans have been recorded stranded in Cornwall since 1990 and 490 were retrieved by volunteers for post mortem examination by the VLA. As Rob Deaville explains, "Since 1990, the CSIP has recorded data on nearly 10,000 individual cetaceans found stranded on UK coasts, 28% of which were found and recorded in Cornwall by the MSN. They and their volunteers have played an absolutely integral part in research into strandings in the UK over the last 20 years and are very much at the centre of the national picture."

Patterns of sightings and strandings of marine turtles over the last 100 years in the South West were discussed by Dr Matthew Witt of the Marine Turtle Research Group, University of Exeter, Cornwall Campus. The three main species recorded in the southwest are the leatherback turtle, a seasonal migrant that comes here to feed on mainly on jellyfish, the Kemp's Ridley and the loggerhead turtle. The last two species are unexpected visitors that have been washed here on the currents of the Gulf Stream from their breeding beaches on the east coast of America, up to 6,000 km away.

As bycatch is the main cause of death among cetaceans in Cornwall, and Cornwall Wildlife Trust has been conducting a trial of 'pingers' (acoustic deterrent devices) on inshore fishing vessels, to test whether mortalities could be reduced. As Tom Hardy, Marine Conservation Officer at the Trust, explained, four fishing boats less than 10 metres in length volunteered to assist in the trial which took place within the 6 nautical mile limit. Acoustic monitoring devices, which record the clicks the animals make when echo-locating, were also attached to the nets to measure the changes in behaviour in response to the pingers.

Although common and bottlenose dolphins showed no apparent regard for the pingers, there was a 48% reduction in the presence of porpoises around the nets with pingers, suggesting that this method does work for this species.

Emma Cunningham, Volunteer Coordinator for the Cornwall Wildlife Trust Seaquest Netsafe project, then explained how volunteers could assist the Trust by joining the sightings team, which is conducting a watch for cetaceans from seven different sites around the coast. The aim is to provide data on inshore cetacean populations and behaviour, through effort based sightings and underwater,passive acoustic monitoring devices placed at specific sites. To date, over 40 volunteers have assisted by collecting hundreds of hours of survey data.

In the final talk of the day, MSN coordinator Jan Loveridge presented the analysis of Cornish strandings data collected by the team during 2010. A total of 45 cetaceans had been recorded, the majority being harbour porpoises and common dolphins. Eleven cetaceans were retrieved for post-mortem examination by the VLA. Among the many notable strandings was a bycaught, white-beaked dolphin that was found at St Mawes, only the ninth of this species ever to be recorded in Cornwall and a 17 metre long fin whale that stranded at Porthtowan - cause of death unknown. Equally notable was a 6 metre long emaciated humpback whale that was originally monitored alive by BDMLR. It was maternally dependent, unable to feed itself and sadly, no practical help could be offered to it. It disappeared and was later found floating dead off St Ives. The MSN team recorded and photographed it and the VLA took samples for DNA analysis.

The Forum was praised by Dr Paul Jepson of the Institute of Zoology in London, "Every year the standard of the Cornwall Wildlife Trust MSN Forum is exceptionally high. It’s now more like an international marine mammal scientific conference in quality, than a local Forum for training volunteers", he says. His comments are echoed by Rob Deaville of the CSIP, "The Forum was, as always, a great success and the standards keep being raised each year."

The Trust's marine work is supported by the Esmée Fairbairn Foundation, the SITA Trust and local organic children’s clothing company, Frugi.