CSI of the Sea: what have we learnt from 30 years of investigating UK strandings?

Rob Deaville

A dolphin is found dead stranded on a remote beach by a dog walker. Why did this event occur? How did it die? Was the stranding natural, or was it caused by our activities? What can we usefully learn from investigation of the stranded animal? And perhaps most importantly, what can both its life and death tell us about the state of the wider marine ecosystem and the impacts we are having upon it?

Striped dolphin stranding © CSIP, ZSL
Striped dolphin stranding © CSIP, ZSL

The UK Cetacean Strandings Investigation Programme (CSIP) was created in September 1990 to help address questions like these. The CSIP is a collaborative research programme led by the Institute of Zoology and funded by UK Government. Its remit over the last 30 years has been the investigation of the causes of strandings of cetaceans (whales, dolphins and porpoises), marine turtles, some shark species and seals around the UK coast, to learn more about the threats these species face in our waters. Over this period, CSIP partner organisations have recorded data on over 17,000 cetacean strandings and investigated more than 4,300 through systematic and forensic post-mortem examinations. The ZSL Science and Conservation event held on Tuesday 11th January will focus on four of these cases, to help shed more light on the work of the CSIP.  

Common dolphin necropsy at ZSL © Greg Norman
Common dolphin necropsy at ZSL © Greg Norman

Since its inception, the CSIP has described the first mass mortality event related to bycatch (accidental capture in fishing gear) in Europe, helped discover a condition analogous to decompression sickness in cetaceans and provided the first evidence of violent and fatal interactions between bottlenose dolphins and harbour porpoises and other species of cetacean. Through its long-term collaboration with the Centre for Environment, Fisheries and Aquaculture Science (Cefas), the CSIP has also produced the world’s largest dataset on chemical pollutant exposure in cetaceans and led to a globally significant body of research on their impacts on marine species. Data from the programme has also recently revealed climate change driven shifts in distribution of some cetacean species. As well as helping support and produce a broad variety of collaborative research, with over 270 peer reviewed publications produced since 1990, its research has helped inform management and policy decisions at a national and international level on anthropogenic pressures ranging from bycatch to chemical pollution. Although strandings research can have many inherent biases, it remains a relatively cost-effective means of investigating threats to marine fauna and generating data on the condition of the marine ecosystem.  

Sei whale found in the Thames drone image © Rob Deaville
Sei whale found in the Thames drone image © Rob Deaville

The success of the CSIP over the last 30 years has relied on the support of a vast number of members of public, volunteers and statutory, educational and voluntary institutions. Without their assistance, many of the achievements of the last 30 years wouldn’t have been possible. To each and every person that helped us out we say a heartfelt thank you, as the programme moves forward into its fourth decade of research on the threats these vulnerable species face in UK waters.

If you find a stranded cetacean, marine turtle, shark or seal, please report it to the CSIP by calling the national hotline on 0800 6520333. 

To find out more about what we've learnt from 30 years of investigating cetacean strandings and hear from some of our partners around the UK, join the free online Science and Conservation Event on Tuesday 11 January:
Click here for event information

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