Press Room

New Seabird Study Highlights Importance of Healthy Forage Fish Populations in Warming World

After 23 years studying the nesting success of puffins, razorbills and murres in the Gulf of Maine, research from Audubon and the University of New Brunswick supports the call for improved protections for forage fish populations.

HOG ISLAND, Maine — Today, the scientific journal Marine Ecology Progress Series (MEPS) published a study that analyzes reproductive success of Atlantic Puffins, Razorbills and Common Murres when preferred, high-energy prey are less available due to warming waters in the Gulf of Maine. Authored by scientists from the Atlantic Laboratory for Avian Research at the University of New Brunswick and the Seabird Restoration Program at the National Audubon Society, the study supports the need to protect and restore forage fish populations along our coasts as climate change increases global ocean temperatures.

“High-quality prey like herring and sand lance are not only an important food source for seabirds, but also for the whole marine food web.  A diversity of healthy stocks of  forage fish is especially important when  warmer waters push high energy forage fish  into deeper water and further from land,” said Dr. Steve Kress, executive director of Audubon’s Seabird Restoration Program and co-author of the study.

“Just like birds on land indicate the health of terrestrial ecosystems, seabirds too can tell us about the state of the ocean which supports both coastal communities and countless wildlife. What they’re saying is very clear: we need to protect and enhance coastal populations of forage fish.”

The study analyzed the three species of seabirds and tracked breeding success, chick condition, and chick diet composition. Significant changes in chick diet were seen across the study period for all three seabird species, coinciding with major temperature increases. The authors concluded that razorbills and murres need a more consistent diet of high-quality forage fish than puffins, which more frequently exploited lower-quality but more readily available food during food shortages.

However, puffin reproductive output was much more vulnerable to ocean warming owing to their longer breeding season. In other words, because they take longer to leave the nest and head to sea to forage on their own, puffin chicks, also known as “pufflings,” are more susceptible to longer periods of low quality fish. Overall, all three species of birds would benefit from stronger management of forage fish populations to secure healthy populations during marine heatwaves.

Now what?

Audubon encourages members and supporters to contact their members of Congress and urge support for the Forage Fish Conservation Act (HR2236), which will expand protections for forage fish in the country’s only fisheries management law, the Magnuson-Stevenson Act. At the moment, the law does not differentiate between forage fish and larger fish, faulting to manage forage fish for their critical role in the ecosystem, as they transfer energy from tiny organisms like zooplankton to larger predators including seabirds, marine mammals, and larger fish.  By updating and improving the Magnuson-Stevenson Act via HR 2236, the foundational fishes of our marine ecosystems can begin to recover and continue supporting the wildlife, people and economies that depend on them.

What are forage fish?

Forage fish are the primary food source for seabirds and include very small fish like sardines, anchovies, and herring; other organisms that serve as seabird food are krill, tiny crabs, and squid. Larger fish like cod, tuna, pollock, and salmon also need these forage species as a food source. Forage fish live off of microscopic plankton and oxygen, both of which are becoming scarcer due to ocean warming and acidification. As high quality plankton move deeper and off-shore or northward to find more oxygen and the cold water they need, forage fish follow them. Seabirds tied to traditional nesting islands during the breeding season can’t always follow the forage fish, however.

 When seabirds do extend their foraging to follow the forage fish, all the travel and deep diving necessary to access their food spends precious energy which makes adults less able to lay eggs, feed and fledge their young. This affects breeding success and can threaten regional populations of seabirds.

 Seabird numbers have declined by 70 percent since 1950 because they are increasingly subject to many stressors, the most harmful being climate change and overfishing.

 Take action with Audubon today by visiting


About Audubon

The National Audubon Society protects birds and the places they need, today and tomorrow. Audubon works throughout the Americas using science, advocacy, education, and on-the-ground conservation. State programs, nature centers, chapters, and partners give Audubon an unparalleled wingspan that reaches millions of people each year to inform, inspire, and unite diverse communities in conservation action. A nonprofit conservation organization since 1905, Audubon believes in a world in which people and wildlife thrive. Learn more at and on Facebook, Twitter and Instagram @audubonsociety.

Contact: Nicolas Gonzalez,, (212) 979-3068


Stay abreast of Audubon

Get updates about our conservation work and how to help birds.