Adapting the sound inside fish’s ear stone helps to trace transition trails
Salmon migration can be followed by listening to ecological data. In a study published in the science journal Heliyon, chemical data describing salmon migration was translated into sound, which can be used to hear how fish transition from the ocean to rivers and from river to river.
Visiting professor Jonathan Middleton from the University of Tampere was one of the researchers in the study together with researchers from the University of Idaho, Eastern-Washington University and the University of Virginia in the United States.
The method describing the paths of migratory fish is called sonification and it enables even untrained listeners to interpret large amounts of complex data, providing a new way to deal with the “big data” problem.
Salmon migration is changing as a result of human impact. In the Snake River in Idaho, United States, the behaviour of young Chinook salmon is evolving rapidly. To understand the changes, the researchers collected detailed information on their movement patterns 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 called an ear stone or otolith. The otolith record contains a lot of detail about where the fish has been and how long it stayed there. Statistical tools cannot capture the nuance of movement timing. Even visual analysis quickly becomes too complex to interpret, so the researchers decided to take a different approach.
According to Jonathan Middleton, the research team wanted to break the mold on traditional approaches to reviewing data and decided to add sounds to the data. This gave them another perceptual field to analyse and interpret their data.
The team tested their approach by presenting the sounds in a survey to untrained listeners. The results showed that the listeners were most sensitive to changes in pitch and tone.
The researchers presented their sound data to groups of listeners with and without visualisations, such as graphs. The listeners identified movements better without the visualisations, suggesting that sound alone is a more effective way to convey data on salmon migration.