‘They’re inherently charismatic’: the amateur sleuths hooked on sea slugs

More and more enthusiasts have fallen in love with this relative of garden dwellers, and are helping ocean science while they’re at it

Two years ago, Libby Keatley was diving off the coast of County Antrim in Northern Ireland when she spotted something unusual. It was a sea slug – or nudibranch – whose transparent body had orange lines running through it and twiggy projections arranged along its back. “It was quite distinctive and not like anything I’d seen before,” she says.

Keatley called over her diving buddy, Bernard Picton, a local marine biologist and pioneer in UK sea slug studies. He scooped it up in a plastic bag and, back at his lab, confirmed it was a newly discovered species. He named it in Keatley’s honour: Dendronotus keatleyae.