A team lead by researchers at Flinders University and Macquarie University unexpectedly found, in the Antarctic, individuals from the pygmy blue whale subspecies (B. m. brevicauda) that inhabits Australian waters, and hybrids between Australian blue whales and the Antarctic blue whale subspecies (B. m.intermedia).
Catherine Attard, a PhD candidate at Macquarie University researching blue whale genetics, said “Our genetic analyses are based on samples collected since 1990. Previous analyses are based on non-genetic, biological data from historical whaling records, which span from 1913 to 1973.”
“Our genetic data unexpectedly found a higher proportion of pygmy blue whales in the Antarctic than the whaling catch data.”
Researchers at Flinders said the findings have major implications.
“This suggests either that climate change has recently pushed Australian whales to colder climates, or that decreases in population size from historical whaling has changed the ecology of the subspecies,” said Dr Luciana Möller of the School of Biological Sciences at Flinders University.
“It could also be due to differences in the methods used to analyse genetic and non-genetic data. However, impacts from climate change or whaling are corroborated by our other genetics analyses that examine evolutionary, rather than recent, timescales”, said Professor Luciano Beheregaray.
Blue whales are currently endangered because of 20th century whaling. The new findings provide crucial information for their conservation.
For example, future monitoring of population numbers should now consider that not all blue whales in the Antarctic are Antarctic blue whales.
The findings are reported in a paper published in the prestigious journal Molecular Ecology.
The paper has been published online (ahead of print publication) and is accessible here.