Whale Migration And Human Movement: A Review

Once a complex and imperfect science of seafarers, studying and tracking the migration routes of whales has become more precise in recent times due to advances in technology. Thanks to non-invasive and satellite tracking capabilities, we can gather more data about whale migration – and their life histories – than ever before. This information can help governing bodies like the International Whaling Commission develop conservation strategies that limit the damaging effects of human activities such as offshore oil drilling on migrating whales. And the stakes are high: by some estimates, humpback whale populations have been depleted by anywhere from 68%-95%, largely due to illegal whaling. Therefore, mitigating additional threats is vital to ensure humpback whale populations continue to grow.

The authors of this study added to a growing pool of data on whale migration by studying the winter range of individual humpback whales throughout the Gulf of Guinea, where offshore hydrocarbon (e.g., oil and gas) exploration and production is expected to increase. The researchers deployed satellite tags on humpbacks along the coast of Gabon, Africa to gather information about the timing, speed, and route of their spring migration. The researchers also assessed the extent to which humpbacks come into contact with man-made threats, including off-shore oil platforms, toxic substances, and shipping lanes.

The resulting data shows that there is a great deal of variation in how often the whales come into contact with these man-made threats. This poses challenges for those attempting to develop strategies that limit this contact. However, the authors also note that all of the whales in their study passed oil platforms that are currently or were previously “associated with exploration (existing oil and gas leases and seismic surveys), development (construction), and production activities.” The authors also found that what looks like a new seasonal migration route overlaps with a major shipping lane, suggesting that whales could be at an increased risk for dangerous encounters with ocean vessels. Based on this and other data, the authors believe that human-whale encounters are likely higher than what they have estimated. How much higher is not known.

This study is a good reminder to advocates that much work needs to be done to help protect aquatic mammals, such as the humpback whale, all over the world. Data showing the movements of individual whales will be essential to that process.