Last Friday, the Cetacean Stranding Investigation Programme (CSIP) confirmed the stranding of a killer whale on the east coast of England. The report had already reached the team at Christmas, but winter break and the location close to a Royal Air Force range had complicated the access.
The animal was a 15ft (4.6 metres) long juvenile killer whale. While the decomposed state made any definite conclusion on the cause of death highly unlikely, anecdotal reports point towards live stranding. The stomach was found to be largely empty besides a large fragment of plastic material in the first stomach. However, this was considered to be an incidental finding and not lethal since it had not caused impaction.
Killer whales are apex predators and thus at the top of the food chain. This makes them very vulnerable to chemical pollutants in the water which amplify along the food chain in a process called biomagnification. CSIP was able to deliver research that showed the significant negative effect high levels of legacy chemical pollutants had (and have) on the populations around Europe. To evaluate the environmental pressure on the priority species further, several tissue samples were taken from the surprisingly intact organs. All well as for chemical pollution research, samples are also used to analyse life history, population genetics and diet of the animal for statistical purposes and future research.
Compared to Scotland, Killer whale strandings are a rare occurrence on the English coasts. This male was only the fifth incident since the begin of the programme in 1990, and an almost twenty-year gap since the last stranding in 2001.
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