Seabirds need ocean-wide protection to survive human impacts

Seabirds are found across the world’s oceans and have unique adaptations that allow them to survive in these often harsh conditions. However, a recent study has exposed a concerning gap in seabird protection, especially in the vast expanse of the Indian Ocean. 

The research highlights the need for ocean-wide protection for seabirds, which are increasingly threatened by the impacts of human activities such as plastic pollution, overfishing, and habitat destruction.

The study, conducted by teams from Exeter, Heriot-Watt, and Réunion universities, along with the Zoological Society of London (ZSL), marks a significant step in marine conservation efforts.

Lack of hotspots 

Unlike other oceans, which are known to have specific “hotspots” where predators, including seabirds, gather in large numbers to feed, the Indian Ocean lacks such concentrated feeding areas. This lack of hotspots is particularly concerning given the various threats seabirds face due to human activities.

Dr. Alice Trevail, a researcher from the Environment and Sustainability Institute at Exeter’s Penryn Campus, emphasized the importance of this discovery. 

“Efforts are being made to protect key breeding colonies, but until now little was known about where Indian Ocean seabirds go when they’re not breeding,” said Dr. Trevail. “We found that seabirds are extremely mobile outside of breeding times, with no focused hotspots.”

This mobility poses a challenge for conservation efforts. The researchers found that even the largest Marine Protected Areas (MPAs) in the Indian Ocean provided limited refuge for these birds, with them spending an average of no more than four days per year in any of the five largest MPAs.

International action is needed

The researchers gathered tracking data on nine seabird species during their non-breeding periods. The data showed that these birds, which primarily feed on small fish, are significantly impacted by human activities like overfishing and pollution.

“As the birds roam widely and spend much of their time outside national waters, we need international action – like the recent High Seas Treaty – to protect them,” said Dr. Trevail. “No country can act in isolation to protect these birds.”

Tropical marine ecosystems

“Tropical marine ecosystems are in urgent need of protection to arrest catastrophic biodiversity loss. Spatial protection of static habitats, such as reefs, seagrass beds, and mangroves, have produced conservation dividends and often include core distributions of resident and breeding species,” wrote the study authors. 

“However, it is more challenging to implement a coherent strategy for mobile marine predators, which play a key role in tropical ecosystem function, especially coral reef conservation.”

Study significance 

The researchers noted that tropical seabird communities are currently a fraction of historic sizes, largely due to the impacts of habitat destruction, human exploitation, invasive species, and overfishing. “Land-based interventions at colonies provide hope for halting and reversing tropical seabird population declines.”

“Nevertheless, threats at sea are more challenging to resolve. This is particularly the case during non-breeding, which can represent >50% of the annual cycle and is when migratory species may cross ocean basins and international boundaries, potentially being exposed to anthropogenic impacts on the high seas and risking high mortality rates,” wrote the researchers.

“It is imperative, therefore, that we gain better knowledge of the migratory range of tropical seabirds and factors driving their at-sea distributions.”

Seabird protection

Seabird conservation is a critical aspect of preserving marine ecosystems, as seabirds are important indicators of ocean health and play vital roles in these environments. However, seabird populations worldwide face numerous threats, leading to declining numbers in many species.

Key threats 

• Overfishing: Reduces the availability of food for seabirds, affecting their ability to survive and reproduce.
• Climate change: Alters oceanic conditions, impacting seabird food sources and breeding habitats.
• Pollution: Oil spills, plastic waste, and chemicals in the oceans can be lethal to seabirds.
• Invasive species: Introduced predators on breeding islands, such as rats and cats, can decimate seabird colonies.
• Human disturbance: Direct disturbance at breeding sites and accidental bycatch in fishing gear also pose significant threats.

Conservation strategies

• Marine Protected Areas (MPAs): Establishing and enforcing MPAs can provide safe havens for seabirds by conserving their feeding and breeding grounds.
• Sustainable fisheries: Implementing sustainable fishing practices helps ensure adequate fish stocks for seabirds.
• Eradication of invasive species: Removing invasive predators from important seabird breeding islands has been highly successful in some areas.
• Pollution control: Efforts to reduce pollution, including oil spills and plastic waste, are crucial.
• Climate change mitigation: Addressing the broader issue of climate change is vital for protecting seabird habitats.
• Research and monitoring: Ongoing research and monitoring are necessary to understand seabird ecology and the effectiveness of conservation measures.

Challenges and opportunities

Despite the challenges, there have been successful conservation stories, such as the recovery of specific seabird species following invasive predator eradication and the establishment of large-scale MPAs. Continued effort and global cooperation remain key to the effective conservation of seabirds.

The study was funded by the Bertarelli Foundation. The findings are published in the journal Current Biology.

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