A new study has revealed fascinating insights into how humpback whales in the southeastern Pacific are adapting their epic migrations in response to changes in the ocean.
The Journey and Why It Matters
Humpback whales undertake one of nature’s most spectacular journeys: from warm tropical waters where they breed, to frigid polar regions where they feed. For the southeastern Pacific population (often called Breeding Stock G), these whales leave breeding grounds off Costa Rica, Panama and Ecuador and head south toward the waters around the Antarctic Peninsula.
Their success depends heavily on reaching the feeding grounds at just the right time — when sea ice has melted and krill — their tiny prey — are abundant.
What the Study Found
Researchers satellite-tagged 42 whales over multiple years (2009–2016) and tracked their paths, behaviour and the ocean conditions they encountered. Nature+1
Some key findings:
- The whales exhibited behaviour associated with feeding (so-called “area-restricted search” behaviour, meaning they slow, circle or forage) during their migration, not just at the feeding grounds. This was more likely when the whales passed through areas of higher marine productivity (more chlorophyll-a) along the coast. Nature
- The timing of their migration also appears to depend both on current cues (what the whale senses locally in the ocean) and on memory or past experience — such as previous ocean conditions at their Antarctic feeding grounds, especially the timing of sea-ice melt. Whales left later when the sea-ice melt was delayed.
- The research suggests that in a changing climate the matching between whale migration, prey availability and environmental cues may become more difficult to maintain — which could threaten how well these whales feed and reproduce long term.
Why It Matters for Conservation
Understanding how and why whales migrate the way they do is crucial for conservation. If whales rely on specific cues (like sea-ice melt or coastal productivity) that are now shifting due to global warming, the whales may arrive at the wrong time or place, potentially missing their food window. That could impact their health, calf survival rates and ultimately population numbers.
A Look Ahead
- Scientists suggest that protecting key marine zones — especially those along migration routes and near feeding grounds — becomes ever more important as conditions change.
- Monitoring the whales’ migration timing and feeding behaviour offers a way to detect early signals of trouble in the ocean ecosystem.
- Lastly, this research invites us to think about the ocean as a dynamic stage: whales are using both what they sense now and what they’ve learned before to navigate. But as climate change accelerates, past experience may no longer be a reliable guide.
In short: These giants of the sea are more adaptive than we may have given them credit for — but even their remarkable migration strategy might be pushed to its limits by rapid environmental change.
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