El Nino events affect whale breeding

New research shows that global climate processes are affecting southern right whales (Eubalaena australis) in the South Atlantic. A thirty-year study by an international team of scientists found a strong relationship between breeding success of whales in the South Atlantic and El Nino in the western Pacific. The results are published this week in the On-line journal Biology Letters.

Southern right whales migrate from the South Atlantic to the Southern Ocean to feed. Scientists know from other studies that following El Nino, changes in sea temperatures affect the availability of krill, a shrimp-like crustacean, which is the main diet of these whales. It is known that these changes affect penguins and seals in the Antarctic, but this is the first time the link has been made with whales as they return to their calving grounds in the South Atlantic.

Keith Reid from British Antarctic Survey (BAS) said, “These results help us to understand processes in three connected oceans and are crucial to predicting the consequences of climate change on the whales.”

Southern right whales have been internationally protected since 1935. Their populations are showing signs of recovery, however, sea surface temperatures in parts of the Southern Ocean have increased by 1°C over the last 50 years and if they continue to rise this could threaten their recovery.