Kategorie: News
New study reveals astonishing migration distances
When coral larvae set off on a long journey: you dive down on the Great Barrier Reef and observe a magnificent Acropora coral. What you cannot see – and would never suspect – is that its offspring could be establishing a new home more than 100 kilometres away – one of the longest migration distances ever recorded for corals.
This previously unknown distance formed the basis of research carried out by an international team from Southern Cross University and the French National Centre for Scientific Research.
Genetic highways in the Pacific
The scientists studied over 1,000 coral colonies across 29 reefs and discovered a fascinating network: the staghorn coral Acropora spathulata forms vast, interconnected populations stretching from the Great Barrier Reef across the Coral Sea to New Caledonia. Their larvae use ocean currents as natural highways.
“On average, parent corals and their offspring live about 100 kilometres apart,” explains Dr Hugo Denis, lead author of the study. This wide distribution could be the key to the reefs’ survival.
For us divers, it is a painful reality: coral reefs worldwide are suffering from heatwaves, crown-of-thorns starfish infestations and cyclones. This is precisely where the value of the far-reaching dispersal of larvae becomes apparent. Following a disaster, surviving neighbouring colonies can repopulate the damaged area.
Even more importantly, populations thousands of kilometres apart occasionally exchange gametes and genetic material. These ‘genetic tools’ help other populations adapt to changing environmental conditions.
Dr Denis compares genetic diversity to a well-stocked toolbox: “The greater the variety of tools, the better a community can solve problems and respond to changing conditions.” The research team discovered that, depending on environmental conditions, Acropora spathulata can host five different species of algae. This flexible partnership could provide the corals with additional avenues for adaptation.
The findings have implications: if coral populations are connected across national borders, isolated marine protected areas are not sufficient. The researchers are calling for international protection networks that follow the natural distribution patterns of the corals. Recent studies by the Leibniz Centre for Tropical Marine Research confirm that many marine protected areas are too small and isolated. Scientists are calling for at least 30 per cent of the ocean’s surface to be protected – within interconnected corridors.
These findings highlight just how interconnected marine ecosystems are. Every reef we visit is part of a larger network. Damage in one place can have far-reaching consequences – but healthy reefs also help damaged areas to recover.
Hope through science
Despite all the challenges, studies such as these offer cause for hope. The ability to disperse offspring over long distances and exchange genetic material is an evolutionary advantage honed over millions of years.
The Reef Restoration and Adaptation Programme is already developing practical applications: scientists are identifying heat-resistant coral lines and actively promoting their dispersal. In Florida, underwater nurseries with transplanted coral fragments are showing quite good survival rates.
However, all experts emphasise that without consistent climate action, even the most resilient corals will not survive in the long term.
The IPCC warns that even with a 1.5-degree rise in temperature, a large proportion of the reefs will suffer severe damage.
The time to act is now
The baby corals, currently somewhere in the Pacific on their 100-kilometre journey, carry the future of their reef ‘parents’ within them. Whether they have a future lies in our hands too.
Denis sums it up: “Nature has shown us that it possesses astonishing mechanisms for adaptation and recovery. Our task is to give it the time and space to utilise these mechanisms.”
Source/Further information:
Current Biology (2026): Denis et al. – https://doi.org/10.1016/j.cub.2026.04.057