Scientists make first observation of fish schooling using bioluminescent flashes

August 14, 2019

A new study is the first to demonstrate that schooling in fishes can be facilitated by bioluminescent flashes in the absence of ambient light. Led by researchers at the American Museum of Natural History, the research raises the possibility that fish schooling may occur in the deep sea, where it was previously assumed to be too dark for fish to coordinate their movements with each other. The study is published today in the journal PLOS ONE.

"Being in the middle of one of these bioluminescing schools was one of the most magical things I've ever experienced as a marine biologist," said lead author David Gruber, a professor of biology at Baruch College and a research associate at the Museum. Gruber was part of the team that serendipitously came across a school of thousands of flashlight fish (Anomalops katoptron) while scuba diving at night off a remote island in the Solomon Islands. "It was like a moment from the film Avatar as we watched rivers of bioluminescent flashes, like a blue-brick road, descend down the reef."

It is estimated that more than 25 percent of the world's fish species school, a collective behavior that is thought to lower the risk of predation, as well as give the fish greater access to food and mates. But schooling fishes rely on their ability to see one another, an idea that is supported by observations of fish schools dispersing at depths with critically low light levels. So when the team of researchers--including John Sparks, a curator in the Museum's Department of Ichthyology, came across schooling flashlight fish in the pitch dark, it was quite the surprise.

"It was simply astonishing--we observed thousands of flashlight fish using synchronized bioluminescent flashes to coordinate their movement and facilitate schooling behavior in complete darkness, a behavior and function that had not previously been reported for bioluminescence," said Sparks, who is senior author on the paper.

Bioluminescence is visible light generated by living things through a chemical reaction. Flashlight fish, which typically hide in reef crevasses and caves during the day and only venture out on moonless nights, have pockets under their eyes that are filled with bioluminescent bacteria manipulated by an organ that allows them to "flash" with different patterns.

The researchers collected footage of the Solomon Islands school--the largest recorded aggregation of bioluminescent flashlight fish, comprised of thousands of individuals--as part of their 2013 trip, and returned to the remote, uninhabited volcanic island in 2016 and 2019 to gather more data. To capture footage of the fish's nighttime behavior in their natural environment, observations had to be made without artificial light. Both scuba divers and a three-person submarine used a suite of low-light cameras, including a custom-built underwater high-speed, high-resolution scientific complementary metal-oxide-semiconductor (sCMOS) camera.

To capture nighttime imagery of the flashlight fish schooling, Brennan Phillips, an assistant professor of ocean engineering at the University of Rhode Island and a coauthor of the study, modified a deep-sea low-light camera system so that it could be utilized by a scuba diver. "Everything had to come together to get these data--the new camera system, the weather, the divers, and, of course, the fish. It was one of the hardest challenges I have faced as a marine roboticist."

Through a combined analysis of field video recordings and modeling, the researchers demonstrate that the flashlight fish are indeed schooling--synchronizing their behavior and swimming in an oriented, polarized manner relative to one another--and not just "shoaling,"a term that describes a loosely organized group of fish.

"Our finding reveals a completely novel function for bioluminescence in the ocean, and shows that fishes are able to school using only the natural light they emit, without the need to rely on ambient light," Sparks said.
For images & video supporting this announcement, please click here.

Other authors on this study include Rory O'Brien, Ganesh Vasan, Peter O'Brien, and Vincent Pieribone, from the Yale University School of Medicine; and Vivek Boominathan and Ashok Veeraraghavan, from Rice University.

The Museum greatly acknowledges the Dalio Foundation for its generous support of the inaugural Explore21 Expedition.

The Museum's Explore21 Initiative is generously supported by the leadership contributions of Katheryn P. and Thomas L. Kempner, Jr.; Linda R. and William E. Macaulay; and the Stavros Niarchos Foundation.

This study is based upon work supported by grants from the National Science Foundation (NSF DEB 1257555 and DBI 1556213), National Oceanographic and Atmospheric Administration (NOAA OER NA160AR0110198), and National Geographic Expedition Council (EC0780-16).


The American Museum of Natural History, founded in 1869 and currently celebrating its 150th anniversary, is one of the world's preeminent scientific, educational, and cultural institutions. The Museum encompasses 45 permanent exhibition halls, including those in the Rose Center for Earth and Space and the Hayden Planetarium, as well as galleries for temporary exhibitions. It is home to the Theodore Roosevelt Memorial, New York State's official memorial to its 33rd governor and the nation's 26th president, and a tribute to Roosevelt's enduring legacy of conservation. The Museum's five active research divisions and three cross-disciplinary centers support approximately 200 scientists, whose work draws on a world-class permanent collection of more than 34 million specimens and artifacts, as well as on specialized collections for frozen tissue and genomic and astrophysical data and on one of the largest natural history libraries in the world. Through its Richard Gilder Graduate School, it is the only American museum authorized to grant the Ph.D. degree and also to grant the Master of Arts in Teaching degree. Annual visitation has grown to approximately 5 million, and the Museum's exhibitions and Space Shows are seen by millions more in venues on six continents. The Museum's website, mobile apps, and massive open online courses (MOOCs) extend its scientific research and collections, exhibitions, and educational programs to additional audiences around the globe. Visit for more information.


Become a fan of the American Museum of Natural History on Facebook at, follow us on Instagram at @AMNH, Tumblr at amnhnyc, or Twitter at @AMNH.

American Museum of Natural History

Related Science Articles from Brightsurf:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.

Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.

Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.

Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.

World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.

PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.

Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.

Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.

Read More: Science News and Science Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to