Scientists Attempt to Explain Southern Right Whale Die-Offs

In an attempt to explain southern right whale die-offs, scientists behind a new study are using satellite tags to remotely track the massive mammals in Argentina and record their every movement.

Southern right whales are known to have breeding and calving grounds in the sheltered bays of Península Valdés, Argentina, however the area where they choose to feed remains unknown, supposedly located somewhere in the western South Atlantic. Researchers believe this information could eventually provide clues to the cause of one of the largest great whale die-off ever recorded.

Over the past decade, about 400 whale calves have died for reasons that still remain unclear. Scientists suggest disease, certain pollutants, and wounding by kelp gulls - a common occurrence in Península Valdés - as possible explanations, but they cannot say for sure.

So, in an attempt to get to the bottom of this conundrum, researchers with the Wildlife Conservation Society (WCS), along with a host of other institutions around the world, have been attaching satellite tags to southern right whales over the last month. So far, they have done so successfully on five of these ocean giants, with hopes of attaching more.

By determining where the whales are feeding, researchers hope to find any threats to the whales along their migration route or on their feeding grounds. Additional research may also establish any issues associated with food or nutritional stress causing calf loss by some mothers.

"Satellite telemetry is the best method to understand the long-term movements and behavior of whales. Tagging individuals of different sex and age classes will let us explore potential differences in how they migrate and use their habitats," Sais Alex Zerbini, a whale telemetry expert from NOAA who was involved in the study, said in a statement.

Growing up to 55 feet in length and weighing up to 60 tons, the southern right whale is the most abundant species of the world's three species of right whale. Unlike the North Atlantic and North Pacific right whales - which are both endangered - southern rights have managed to rebound from centuries of hunting by humans. Once on the verge of extinction, their numbers have now grown seven percent annually since 1970. But with these latest mind-boggling die-offs, conservationists worry it may impede their recovery.

"As the tags continue to transmit," added Dr. Howard Rosenbaum of WCS, "we hope our whales lead us to new insights about their lives in the vastness of the South Atlantic and provide possible clues related to the die-off."