Cod Songs
music from a fish's ear
Project Breathless researchers learn about an individual fish’s life history by examining the growth rings on its ear stones (otoliths), tiny structures that are part of its hearing & balance system. We also analyze the chemistry of the ear stones. Certain trace elements that deposit on an ear stone indicate underwater conditions the fish encountered during its lifetime, while other trace elements suggest details about the fish’s health:
Phosphorus – related to growth
Magnesium – a function of metabolism
Barium –indicates the fish spent time in nearshore waters.
Strontium – related to salinity. Present in salt water, but not usually found in freshwater, strontium can be used to track a fish’s seasonal movements
Manganese – usually found in solid form, manganese dissolves in water only under low-oxygen conditions. If a fish has higher amounts of manganese deposited on its ear stone, it is likely that it encountered hypoxic water
Project Breathless team members Karin Limburg and Elizabeth LoGiudice converted the chemical data from the ear stones of five individual Baltic Sea cod into audible tones using an open source data sonification tool called Two Tone.
They made music from the sounds, and these 'cod songs' interpret each fish's life story. Ear stones grow like a tree, adding annual growth rings that reveal details about the conditions where a fish swam. Each cod song reflects the lifetime of the fish - from birth to death - and the songs end abruptly, signifying that the cod was caught and died.
Fishes are described as "happy" if the data from the chemical trace elements present in their ear stones indicate that they lived in good quality water, and "unhappy" if the data indicates they encountered low-oxygen, or hypoxic, conditions during their lives.
Song of a Stone Age Cod ~ A Very Happy Fish
This cod song was composed from chemical data extracted from the ear stone of a Baltic cod that lived 4,500-5000 years ago. The ear stones were excavated from a site on Gotland Island by archeologist Dr. Carina Olson. Although this fish lived a relatively short life of 3.5 years before being caught, it grew at a faster rate than modern cod, and the chemical trace elements deposited on the ear stone suggest it lived a good life, free from hypoxia.
In this song, Magnesium (Mg), which reflects a fish's metabolism, is performed as a steady beat on the marimba. Strontium (Sr) is related to salinity - more strontium in an ear stone equates to more time spent in the ocean. It's played as a trumpet. Barium (Ba) indicates the fish spent time in near-shore, coastal waters, often in early life, and is sonified as an organ.
Strontium (purple) indicates when the fish swam in ocean waters. Barium (red) indicates when the fish swam in near-shore, coastal areas.
Song of a 1930's Cod ~ A Happy Fish Indeed
This nine-year old fish died in 1939. This fish swam in well-oxygenated water and lived a good life, with strong growth seen on its ear stone, and reflected in its earstone chemistry. This ear stone is one that Project Breathless team member Yvette Heimbrand studied for her PhD research at SLU.
This cod song features Magnesium (Mg), reflecting the fish’s steady metabolism, played by a marimba and Phosphorus (P), indicating growth, on trumpet.
Song of a 1990's Cod ~ A Somewhat Happy Fish
The data used in this song was gleaned from the ear stone of a fish that died in 1995. The cod encountered hypoxic conditions early in life, but water quality improved due to a major inflow of oxygen-rich water entering the Baltic from the North Sea. After a rough start, this fish lived most of its life in healthy water.
This cod song introduces Manganese (Mn), the trace element that indicates that a fish spent time in hypoxic water. The stone age and 1939 cod had negligible amounts of Mn on their ear stones, but it is present the 1995 cod ear stone. Mn is performed on piano and violin, distorted through the use of digital effects to help the listener imagine the disorientation caused by lack of oxygen.
This cod song also features Magnesium (Mg), the metabolism biomarker, played on piano during hypoxic periods and on marimba when the fish swam in well-oxygenated water. The ratio of Strontium (Sr) to Barium (Ba) is played on the organ during hypoxic periods and on trumpet when the fish encountered good water quality. Sr is related to salinity and indicates the fish swam in the open ocean, while Ba indicates the fish spent time in coastal waters.
Song of a 21st Century Cod ~ A Very Unhappy Fish
This fish lived in the early 2010's and encountered low-oxygen conditions for much of its life. Its growth was stunted and its metabolism was impacted by the hypoxia it endured during its 5 years of life. It died in 2015.
This cod song features Manganese (Mn), the trace element that indicates that a fish spent time in hypoxic water. The Mn is performed on violin, distorted through the use of effects and tempo changes to help the listener imagine the disorientation caused by lack of oxygen.
This cod song also features Magnesium (Mg), the metabolism biomarker, played on piano.
Song of a Modern Cod ~ A Fish of Changing Fortunes
This cod song was composed using data from the ear stone of a modern-day fish that was born into hypoxic conditions. Much of its early life was spent in low-oxygen waters, impacting its health and growth. It was captured and brought to the Baltic Sea Science Center at the Skansen Museum in Stockholm Sweden, where it grew robustly during the year it lived in the aquarium there. It died in 2020.
This song features Magnesium played on piano and marimba; Manganese (hypoxia proxy) played on distorted piano and violin; and Phosphorus, an indicator of growth, played on the trumpet. Note how the trumpet swells at the end of the song, when the fish experienced rapid growth while enjoying adequate oxygen and food at the Baltic Sea Science Center.
Copyright © Karin Limburg, Elizabeth LoGiudice, SUNY, RF SUNY / 2020, 2021. All rights reserved. These Cod Songs may not be published, reproduced, displayed, modified or distributed without the express prior written permission of the copyright holder. For permission, contact [klimburg@esf.edu].