I saw a ghost at the Vancouver Aquarium last summer. I was walking out of a room overlooking the main shark tank when I saw something in a glass cage embedded in the wall, something small, black and yellow. I mean Black and Yellow—colours so intense that you almost expect to turn the creature over and find a country of origin embossed on its underside. It was a Panamanian golden frog, and it is extinct in the wild. It only survives in zoos and aquariums. It is an ecological phantom, a ghost of nature.

Several factors took the frog to the edge of oblivion but the one that landed the most punishing blows was a chytrid fungus called Batrachochytrium