Humpback Whale Movement Overlaps with West African Shipping Lanes and Oil Rigs, Study Finds

Humpback whales that gather for mating and childbirth off the coast of West Africa are sharing the territory with major shipping routes, offshore oil platforms and chemical hazards, according to a joint study by the Wildlife Conservation Society, the American Museum of Natural History and several leading universities.

By tagging humpback whales with satellites tracking devices and cross-referencing the whales' location data with the locations of major shipping lanes and oil exploration projects, the researchers were able to quantify the overlap of the whales' position with the location of human activity potentially hazardous to the whales.

"Throughout numerous coastal and offshore areas, important whale habitats and migration routes are increasingly overlapping with industrial development, a scenario we have quantified for the first time in the eastern South Atlantic," said Howard Rosenbaum, director of WCS's Ocean Giants Program. "Studies such as this one are crucial for identifying important habitats for humpback whales and how to best protect these populations from potential impacts associated with hydrocarbon exploration and production, shipping, and other forms of coastal and offshore activities."

The research, published in the journal Conservation Biology, tracked the movements of 15 individual humpback whales off the coast of Gabon in 2002 between August and September. While similar movement studies have been conducted on humpback whale populations in other parts of the ocean, this is the first in-depth analysis of humpbacks in the eastern South Atlantic.

"The major goal of the study was to elucidate the unknown migratory movement of whales from breeding areas off western Africa to areas where the whales likely feed in Antarctic or sub-Antarctic waters," the WCS said in a statement.

The tagged whales collectively traveled more than 25,000 miles during the two-month study period, with each whale traveling an average of 1,936 miles. The tags were capable of transmitting data for about 100 days. Two of the tagged whales journeyed from near the equator to the sub-Antarctic ice shelf - nearly 5,000 miles.

"Whales make some of the most fascinating migrations of any animals in the world," said Sara Maxwell, a researcher affiliated with the Stanford Woods Institute for the Environment and a study co-author. "As part of this study, we uncovered previously unknown migration routes of some of the world's largest whales, showing that even today we are still in an age of discovery for these ocean giants."

The researchers found that the whales, overall, spent 76 percent of their time within 200 nautical miles of the coasts of 13 African nations, primarily Cameroon, Gabon, Nigeria and Angola. Whales traveling north from Gabon spent an estimated 41 percent of their time in the presence of oil and gas platforms, the researchers said.

"From understanding which habitats are most important to tracking their migrations, our work provides great insights into the current issues confronting these whales and how to best engage ocean industries to better protect and ensure the recovery of these leviathans," Rosenbaum added.