Cod Songs

Baltic Cod Ballads

Cod (Gadus morhua callarias) are an important fish in the Baltic environmentally and commercially. But their populations are declining and restoration efforts have not yet resulted in their recovery.

Researchers at the Swedish University of Agricultural Science and SUNY ESF seek to increase understanding of the effects of hypoxia on Baltic cod through analysis of data collected from their ear stones.

Five songs were composed with ear stone data gathered from five individual Baltic codfish. They lived during different time periods and under varying environmental conditions, which are reflected by the musical components of each fish's song.

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.

Cod Songs video produced for the Baltic Sea Science Center at Skansen in Stockholm, Sweden. Produced by Elizabeth LoGiudice with Anna Björn, Yvette Heimbrand and Karin Limburg.Footage provided by Deep Sea Reporter & Shutterstock.com.

Song of a Stone Age Cod ~ A Very Happy Fish

Earstones from stone age cod.

Song of a Neolithic Cod compressed.mp4

This 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.

Magnesium (above) reflects metabolic rate, and therefore is a “clock” or “metronome” of a fish’s life.

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.

A computer image of the 1930's cod earstone reveals its growth rings. Each annual ring is made up of a light bands, indicate summertime growth and a dark band indicating wintertime.

Magnesium (above) reflects metabolic rate, and therefore is a “clock” or “metronome” of a fish’s life. Played by the marimba.

Phosphorus indicates growth and is played by the trumpet.

Song of a 1990's Cod ~ A Somewhat Happy Fish

A computer image of the earstone from the 1990's cod.

1995 Cod - "A mostly happy fish" FINAL_MgCa (piano & marimba), inverted MnMg (norm violin), (hypoxic piano w effects), SrBa (organ)_Bm to Dmaj.m4a

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.

Magnesium (above) reflects metabolic rate, and therefore is a “clock” or “metronome” of a fish’s life. Red indicates periods when the fish swam in hypoxic waters.

When present in higher amounts Manganese indicates that a fish encountered hypoxic conditions. Red indicates when the fish was in hypoxic water.

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 21st Century Cod.mp4

Magnesium, played on the piano, indicates metabolism. Red lines indicate periods when the cod encountered hypoxic water.

Manganese, played on distorted violin, is an indicator of hypoxic conditions. When the amount of Manganese in an earstone is high, it indicates exposure to low-oxygen conditions. For this chart, and in this song, we inverted the Manganese data to approximate the sluggish, disoriented feeling of oxygen deprivation.

Song of a Modern Cod ~ A Fish of Changing Fortunes

Earstone of the Cod of Changing Fortunes. Yellow arrow on the left indicates when the fish moved to the aquarium at Baltic Sea Science Center.

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.

Magnesium, played on the piano, indicates metabolism. Red lines indicate periods when the cod encountered hypoxic water. Blue indicates well-oxygenated water. Green indicates when the fish lived in the aquarium at the Baltic Sea Science Center.

Manganese, played on distorted piano and violin, is an indicator of hypoxic conditions. When the amount of Manganese in an earstone is high, it indicates exposure to low-oxygen conditions. For this chart, and in this song, we inverted the Manganese data to approximate the sluggish, disoriented feeling of oxygen deprivation. Red indicates periods when the cod encountered hypoxic water. Blue indicates well-oxygenated water. Green indicates when the fish lived in the aquarium at the Baltic Sea Science Center.

Phosphorus indicates growth and is played by the trumpet. Note the fish's growth spurt while the fish lived in the aquarium at the Baltic Sea Science Center. Red indicates periods when the cod encountered hypoxic water. Blue indicates well-oxygenated water. Green indicates when the fish lived in the aquarium 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].

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