LOST SOULS

In May, a minke whale got lost in the Thames, capturing the nation's interest. But why do whales swim up rivers? And how can they be helped?

- Jo Caird

The arrival of a whale in a city river never fails to capture the imagination. It’s hard to articulate why: there’s something otherworldly, almost magical, about these unknowable creatures from the deep sea making a sojourn into our busy, urban lives.

Whatever the reason for our fascination, when whales swim up rivers – whether it’s the Thames, the Trent or the Clyde, their appearance always draws a crowd. Take the juvenile minke that turned up in the Thames at Teddington Lock in May. Hundreds of onlookers lined the riverbanks, hoping to catch a glimpse of the stricken creature, while news helicopters overhead reported on its every move – and those of the rescue teams trying to save its life.

Around 1,000 cetaceans – that’s whales, dolphins and porpoises – become stranded in the UK each year, according to the UK Cetacean Strandings Investigation Programme (CSIP). Funded by the British government and its counterparts in Scotland and Wales, the programme’s scientists investigate 100 to 150 of these events annually, conducting post-mortems that provide data on causes of death, disease, diet and the general health of cetaceans in UK waters.

Strandings in rivers make up a tiny proportion of the total – less than 1 per cent, estimates cetologist Rob Deaville, CSIP’s project manager – with the overwhelming majority of cetaceans who get stuck high and dry doing so on the coast.