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Listening to data could be the best way to track salmon migration

Turning data from salmon ear stones into sound can help citizen scientists track their movement


London, Feb. 21, 2018 - Sound could be the key to understanding ecological data: in a new study in Heliyon, researchers have turned chemical data that shows salmon migration patterns into sound, helping people hear when they move towards the ocean from one river to another. The approach - called sonification - enables even untrained listeners to interpret large amounts of complex data, providing an easier way to interpret "big data."

The authors, from the University of Idaho, Eastern Washington University and University of Virginia in the US, and the University of Tampere in Finland, say turning salmon migration data into sound could help scientists feel less overwhelmed by interpreting big data. As a result, they may be more engaged with the experience, leading them to spend more time exploring big data in a meaningful way.

"We have shown that it is possible to convey salmon movement using sound alone, and that people without prior training can intuitively determine when fish transition from one river to another," said Dr. Jens Hegg, first author of the study from the University of Idaho. "Our study is the first step in creating this sort of audio display, which could be a very helpful way to explore large datasets."

Salmon migration is changing as a result of human impact; in the Snake River in Idaho, USA, the behavior of young Chinook salmon is evolving rapidly. To understand the changes, researchers need to study their movement patterns in detail, over large geographical areas and short time scales.

One way to track their movement is by studying the chemistry of the salmon's balance and hearing organ - an ear stone, called an otolith. The fish's movements are recorded in the otolith like tree rings, with chemicals being deposited every day the fish is alive. The otolith record contains details about where the fish has been and how long it stayed there, but statistical tools don't capture the nuances of movement timing. Visual analysis quickly becomes too complex to interpret, so the team decided to take a different approach.

"Most scientists rely on visual displays of their data in the form of tables and graphs," said Prof. Jonathan Middleton, one of the authors of the study from Eastern Washington University and the University of Tampere. "Our research team wanted to break the mold on traditional approaches to reviewing data: we are proposing to add sounds as an auditory representation, giving scientists another perceptual field to analyze and interpret their data."

The team tested their approach by presenting the sounds in a survey to untrained listeners. They asked the listeners to identify movements, with an increasing number of fish. The results showed that the listeners were most sensitive to changes in pitch and tone, and that the group performed better as a whole compared to individuals alone.

They also presented the sonifications with and without visualizations of the data, such as graphs. The listeners identified movements better without the visualizations, suggesting sound alone is a more effective way to convey the salmon migration data.

The results suggest sonification could be a useful way to process data for crowdsourcing, and the approach might also translate to other areas of ecology. For salmon migration, there's still a way to go: now that they have shown the approach has potential, in order to apply the approach, the team will need to create tools to explore the detailed data from otoliths using sound.

"Our ears are highly analytical organs that give us much more information than we realize in all aspects of our lives, and we can harness that to learn things about the world in new ways," said Dr. Hegg. "It is always a gamble to reach beyond your comfort zone and try something completely crazy. Without combining across disciplines, and having faith in other ways of looking at things across the spectrum from science to art, these approaches that sound crazy but have potential wouldn't get a chance to succeed."


Notes for editors:

The article is "The Sound of Migration: Exploring data sonification as a means of interpreting multivariate salmon movement datasets" by Jens Hegg et al. (DOI: 10.1016/j.heliyon.2018.e00532). The article appears in Heliyon (February 2018), published by Elsevier.

For a copy of this paper, please contact Victoria Howard at or Journalists wishing to interview the authors should contact the following institution contacts:

University of Idaho: Sara Zaske,

Eastern Washington University: David Meany,

University of Tampere: General Press Mailbox,; Achté Pirjo:

In online coverage of this paper, please mention the journal Heliyon and link to the paper at


This video accompanies the fully orchestrated sonification, containing the sounds from all the fish that were analyzed. It shows where the Snake River is, where fish are born within it, and then visually represents their movement to the ocean along with the sonification:

About Heliyon

Heliyon is an open access journal from Elsevier that publishes robust research across all disciplines. The journal's team of experts ensures that each paper meeting their rigorous criteria is published quickly and distributed widely. Led by Dr. Claudia Lupp, the editorial team consists of over 900 active researchers who review papers on their merit, validity, and technical and ethical soundness. All published papers are immediately and permanently available on both and ScienceDirect.

About Elsevier

Elsevier is a global information analytics business that helps institutions and professionals progress science, advance healthcare and improve performance for the benefit of humanity. Elsevier provides digital solutions and tools in the areas of strategic research management, R&D performance, clinical decision support, and professional education; including ScienceDirect, Scopus, Scival, ClinicalKey and Sherpath. Elsevier publishes over 2,500 digitized journals, including The Lancet and Cell, more than 35,000 e-book titles and many iconic reference works, including Gray's Anatomy. Elsevier is part of RELX Group, a global provider of information and analytics for professionals and business customers across industries.

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