Seabird Die-Offs Linked to Warming Oceans: A Threat to Marine Ecosystems

Delayed Effect of Marine Heat Waves on Seabirds

Persistent marine heat waves lead to massive seabird die-offs months later, according to a new study. The study used data collected by coastal residents to understand the impact of warming oceans on marine birds. A warmer ocean can result in the death of hundreds of thousands to millions of marine birds within one to six months of the temperature increase.

Marine heat waves, including the infamous 'blob' off the Pacific Northwest, have gained attention in recent years. This study takes a broader approach, measuring the magnitude of mortality events across multiple species.

Unprecedented Frequency of Massive Die-Offs

Between 2014 and 2019, there were five massive mortality events, each likely exceeding a quarter million birds. Lead author Timothy Jones describes these die-offs as catastrophic storms hitting without fail every year. The analysis revealed that these extraordinary die-offs were statistically linked to persistently warmer conditions in the Northeast Pacific.

Seabird species such as common murres, puffins, auklets, and shearwaters were particularly affected. The study used data from over 90,000 surveys of 106 seabird species on more than 1,000 beaches, collected by citizen science projects.

Causes of Die-Offs and Impact on Seabirds

The causes of the massive die-offs varied, but all were related to warming. Warmer water can promote harmful algal blooms and increase the likelihood of disease outbreaks, both of which led to seabird mortality events during the study period. Additionally, prolonged ocean warming changed the type, abundance, and nutritional value of seabirds' prey, resulting in widespread starvation.

The study highlights the intensity of warming and its impact on marine ecosystems. The findings underscore the urgent need for global efforts to mitigate climate change and protect vulnerable marine species.

Citizen Science and Collaborative Research

The study's data collection relied on the efforts of coastal residents and citizen science projects. More than 90,000 surveys of beach-cast birds from 1993 to 2021 were included in the analysis, covering a vast area from central California to Alaska. The Coastal Observation and Seabird Survey Team (COASST) played a significant role in collecting data, along with other organizations.

The study involved multiple organizations and thousands of participants, including undergraduate interns, demonstrating the power of collaborative research and citizen science.

Implications for Marine Ecosystems

Seabirds play a crucial role as top predators, and their population decline can disrupt the balance of the nearshore marine environment. The loss of hundreds of thousands to millions of marine birds due to marine heat waves has cascading effects on the food web and ecosystem dynamics.

The study emphasizes the need for proactive measures to address climate change and its impacts on marine life. Efforts to reduce greenhouse gas emissions and implement sustainable practices are crucial to safeguarding the health and resilience of marine ecosystems.

Conclusion: Urgent Action Needed to Protect Seabirds

A new study reveals the devastating impact of marine heat waves on seabird populations. The research found that persistent warming of the ocean can lead to massive die-offs of marine birds months later. Unprecedented in frequency, between 2014 and 2019, there were five massive mortality events exceeding a quarter million birds. The study underscores the urgent need for global action to mitigate climate change and protect vulnerable marine species.


Hannah Hickey-U. Washington. (July 11, 2023). Seabird die-offs follow ocean heat waves.

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