Researchers report a significant decline in calf production among southern right whales off South Africa: mothers now calve every four to five years rather than the historical three-year interval. Warming Southern Ocean waters and a roughly 15%–30% loss of sea ice have reduced krill habitat, forcing whales to travel farther and arrive at breeding grounds in poorer condition. Scientists are using satellite tags, genetic analyses and long-term surveys to monitor the problem, while conservation groups press for stronger protections and policies to reduce climate warming.
Scientists Raise Alarm as Southern Right Whale Births Plummet Off South Africa
Researchers report a significant decline in calf production among southern right whales off South Africa: mothers now calve every four to five years rather than the historical three-year interval. Warming Southern Ocean waters and a roughly 15%–30% loss of sea ice have reduced krill habitat, forcing whales to travel farther and arrive at breeding grounds in poorer condition. Scientists are using satellite tags, genetic analyses and long-term surveys to monitor the problem, while conservation groups press for stronger protections and policies to reduce climate warming.
07:29, 09.11.2025Environment
Southern right whales are calving less often — and scientists are worried
Researchers monitoring southern right whales off the coast of South Africa have documented a worrying decline in calf production, a development that signals not only a threat to the species but also broader stress in ocean ecosystems.
Matthew Germishuizen, reporting in The Conversation, found that female southern right whales — whose populations were recovering after centuries of commercial whaling — are showing signs of malnutrition and slowed reproduction. Historically, mothers calved about every three years; since roughly 2009 that interval has stretched to four or five years, suggesting it now takes longer for females to build the energy reserves needed for healthy pregnancies.
What’s driving the change?
Decades of survey data and recent satellite tracking point to a major driver: warming waters around Antarctica are reducing sea ice and the abundance of krill, the tiny crustaceans that form the foundation of the whales’ diet. Sea ice in some key regions has decreased by approximately 15%–30%, shrinking nursery habitat for krill and forcing whales to travel farther and expend more energy to feed.
“Protecting whales and the oceans they depend on is inseparable from protecting our own future,” Germishuizen writes.
Why this matters beyond whales
The Southern Ocean plays a critical role in absorbing heat and carbon dioxide and in regulating global climate. Changes to Antarctic ecosystems can ripple through fisheries, weather patterns and food security worldwide. If the current trend continues, southern right whale populations could decline again after decades of recovery — a major setback for conservation and for coastal communities that rely on whale-watching tourism.
What researchers and conservationists are doing
Scientists are deploying satellite tags, conducting genetic studies and maintaining long-term monitoring programs to understand how whales are adapting. Conservation organisations, including the Dyer Island Conservation Trust and Whale Coast Conservation, are raising awareness and calling for stronger protection of marine habitats.
How the public can help
Individuals can support the health of marine ecosystems by choosing sustainable seafood, backing policies that cut planet-heating emissions, and supporting the transition to clean energy. Local and global actions that reduce carbon pollution and protect critical habitats are essential to preserving krill populations, feeding grounds and the whales that depend on them.