The unusual spike in the number of dead whales found on the beaches of the southern Argentine province of Chubut in October and November has caused concern at the Whale Conservation Institute (ICB). The annual average in recent years was about 40 whales, but it more than doubled to 85 this year, ICB coordinator Roxana Schteinbarg told Tierramérica.

Some experts attribute the phenomenon to a health problem afflicting the species, while others suggest environmental factors, but it can't be determined for sure until test results are in, she said.

For the past five years, ICB and other groups have been conducting the southern right whale monitoring program. The species numbers about 5,300 in the waters around the Valdés Peninsula, on the Chubut coast.