Dr Liz Chadwick has led the globally important, 35 year-long study and archive called the Cardiff Otter Project since 2004. She and her colleagues and doctoral students autopsy and preserve samples from the bodies of otters who have been found dead (usually they have been run over) across the UK.
As Liz shows me the lab and the archive, we discuss the main focus of their research - toxicology, critically important to our understanding of rivers because chemicals accumulate in otters bodies, and reveal the changing state of the rivers over time.
Liz talks about the worst kind of pollution - Persistent, Cumulative and Toxic. Sewage, for all its faults and yuk factor, is none of these per se. PCBs were banned in 2001 but still turn up in all the otters. Otters were nearly wiped out in the UK by DDT type pesticide use, and though populations have recovered since they were banned, these toxins are still present in all otters livers, just in lower concentrations. PFAs are the contemporary equivalent, the ‘forever chemicals’ of our pans and waterproofs. Fire retardants are another source. As one specific chemical is banned, another is invented. We urgently need to CHANGE this terrible game.
The Otter Project stores tissue from the otters collected in a freezer archive, as a resource for future investigation. Questions will arise and techniques will be invented that make the collection a potential time machine of otter, and river, knowledge.
We talk about difficult choices, the hormones and medicines people take that would be hard (impossible?) to give up, but leach into rivers and negatively impact on aquatic species. We also talk about the much more fun enquiries they are leading on, such as how DNA testing of otter spraint has built a picture of otter diversity around the country, and given some glimpses into individual otter activities.