Male cod may ‘sing’ to females during mating, suggests a new study investigating the sounds cod and pollack produce during the spawning season.
The research, published in the Journal of Fish Biology, aimed to learn more about these noises, and why the fish make them. They discovered that the grunts were produced in rhythmic patterns, suggesting that the females in the shoal may use these rhythms to choose a mate.
To investigate the noises, the team studied two populations of fish in tanks at a fishery in Scotland. Cod, had previously been recorded making grunting noises as they got ready to spawn, but the pollack’s grunt had never been recorded until now. You can hear the grunts produced in the recordings on this page.
‘We already knew male cod produce these sounds, we just wanted to dig a bit deeper, and find out if the sound changed over time to indicate that a spawning event might be occurring. But it was really exciting to find pollack also produce these sounds,’ says Lindsay Wilson, a NERC-funded PhD student at the Scottish Association for Marine Science (SAMS) who led the research.