Opportunities to see this spectacle have been remarkably frequent in the last few months, with 7 strandings of sperm whales in the UK and ~30 in total around the European coasts of the North Sea. This has left people asking:“why is this happening?"
What we do know is that sperm whale strandings have been a common event in the North Sea for over 350 years. In fact there was a peak in strandings during the 18th century, so I‘m a little sceptical about pointing the finger at navy sonar or wind farms. Instead, it seems that the shallow North Sea may act as a trap for this species that is more at home in deep ocean habitats.
The lack of any sightings in the English Channel suggests that they never make it back out to deep water this way. Instead they become funnelled into ever shallower water, possibly getting disorientated and malnourished because their normal squid diet are deep water species. Eventually they get stuck on shallow beaches and once this happens there is little hope for survival.
But what makes some whales take the wrong turn into the North Sea in the first place? There are certainly peaks in the number of strandings over time, which has led some scientists to try and correlate these peaks with external factors.
G.J. Pierce, M.B. Santos, C. Smeenk, A. Saveliev, A.F. Zuur (2007) Historical trends in the incidence of strandings of sperm whales (Physeter macrocephalus) on North Sea coasts: An association with positive temperature anomalies. Fisheries Research, 87: 219-228. doi:10.1016/j.fishres.2007.06.001