Gannet Colonies Could Take 15 Years to Recover From Devastating Bird Flu Outbreak, Scientists Warn
New research reveals that some of the world’s largest northern gannet colonies may need more than a decade to recover after avian influenza wiped out thousands of breeding seabirds, raising fresh concerns over marine ecosystem resilience.
The recovery of northern gannet populations across the United Kingdom could take as long as 15 years following the catastrophic outbreak of highly pathogenic avian influenza (HPAI), according to new scientific research that highlights the long-term ecological consequences of the disease.
Researchers studying major breeding colonies found that the 2022 bird flu epidemic caused unprecedented mortality among adult breeding birds. Because gannets are slow to reproduce, replacing lost breeding adults will take many years even if no further large-scale outbreaks occur.
Among the colonies examined were internationally important nesting sites such as Bass Rock in Scotland and Grassholm in Wales, both of which support some of the largest northern gannet populations in the world. Scientists estimate that these colonies may not regain their pre-outbreak numbers until around the early 2040s under favourable conditions.
The H5N1 strain of avian influenza swept through seabird colonies across Europe during 2022, killing tens of thousands of birds. Northern gannets were among the hardest-hit species because they breed in dense colonies, allowing the virus to spread rapidly during the nesting season.
Unlike many smaller bird species, northern gannets do not breed until they are around four to five years old and typically raise only one chick each breeding season. Their slow reproductive cycle means that even modest population losses require many years to reverse, making recovery particularly challenging after a mass mortality event.
Scientists caution that additional pressures—including climate change, declining fish stocks, marine pollution and human disturbance—could further delay recovery if they continue alongside periodic disease outbreaks. Conservation experts argue that reducing these stresses is essential to give seabird populations the best chance of rebuilding.
Encouragingly, researchers have observed signs that some surviving gannets may possess partial immunity after exposure to the virus. However, the extent and duration of that protection remain uncertain, and experts say continued monitoring is necessary before concluding that future outbreaks will be less severe.
The findings underscore how a single disease outbreak can reshape wildlife populations for decades. As seabirds play a crucial role in marine ecosystems and serve as indicators of ocean health, scientists say protecting breeding habitats and strengthening long-term conservation measures will be critical to ensuring the recovery of northern gannet colonies in the years ahead.
