Scubaism

The study of eight groups of pups born between 1991 and 2001 off Kangaroo Island in Australia found the average survival rate was about 50 per cent. But after a significant El Nino event, when the sea surface temperature lifted, survival of two of the groups dropped to 27 and 18 per cent. Pup survival increased for the 2001-02 group, when the El Nino moderated.

Latrobe University PhD student Rebecca McIntosh, who carried out the study, said: “With the warming of sea surface temperatures, we might see more of this happening.” Ms McIntosh said the waters south of Kangaroo Island usually had cold water rising from the deep, which increased ocean productivity, resulting in more feed for the sea lions. But when an El Nino took place, water warmed and food supplies dropped.