Over the past decade carcasses of almost 500 young southern right whales (Eubalaena australis) have washed up on the Argentinian Valdés Peninsula, one of the species key calving areas. Now the UK Department for Environment, Food and Rural Affairs (DEFRA) along with the EU are launching an investigation into the unexplained deaths of this vulnerable marine species.
The $925,000 project involves tagging the whales and calves and tracking them by satellite. They will also identify the individuals by taking DNA samples.
“There are only a few thousand southern right whales left on the planet,” told The Guardian the project’s leader, geneticist Jennifer Jackson, of the British Antarctic Survey, Cambridge. “We need to find out what is killing them and we think their sub-Antarctic feeding ground holds the answer.”
Three theories have been put forward to explain the deaths:
- Lack of food: krill may be disappearing in whale feeding areas at South Georgia.
- Exposure to toxic algae
- Kelp gulls: there has been a rise in attacks by kelp gulls on young whales since the 1970’s. This could be damaging their health and triggering the jump in deaths.
The lack of food theory seems to be the strongest as previous studies have shown unusually warm summers off South Georgia decrease whale calving rates the following year. “The trouble is that we know so little about the lives of southern right whales,” said Jackson. “That is why we are going to spend the next two years studying them in great detail.”
The team hopes to understand how the southern right whales live their lives and what may influence their health and reproduction. “Once we have done that we hope we will a much clearer idea of what is happening to them and so be able to do something about that,” said Jackson.
Southern right whales can grow up to 18 meters and weigh up to 80 tons. Their name comes from being the right whale for whalers to pursue. They swim slowly, float when dead and yield a lot of oil. Also, mother whales are extremely protective so when swimming in shallow coastal waters they were easily picked off by harpoon.
From an estimated several hundred thousand population in the 18th century, the southern right whale’s numbers crashed and plunged towards extinction. After the 1940’s they slowly recovered because of a moratorium was agreed. Then in the 1970’s levels plunged again due to illegal hunting by Soviet whalers. Today numbers are estimated to be around 12,000.