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CO2 Binges During Larva State Befuddle Fish

A study published this week shows that fish larvae exposed to elevated levels of CO2 in their larvae state are heedless to the scent of proximate predators.


Photo: Mshai

When CO2 levels reached 700 parts-per-million, scientists reported noticeable reckless behavior in the fish test subjects.

Young humans aren’t the only animal to engage in reckless behavior when exposed to controlled substances. Young fish do, too!

A study published this week in the Proceedings of the National Institute of Sciences (PNAS), shows that clownfish and damselfish larvae exposed to elevated levels of carbon dioxide in their larvae state are heedless to the scent of proximate predators.

Scientists are unsure if this behavior stems from CO2 masking the scent of predators in the water, or if the gas actually alters the scent receptors in the fishes’ brains.

Regardless of the means by which the behavior is produced, it is the behavior’s effect that alarms scientists.

The mortality rate of the test fish skyrocketed due to their increased inability to avoid predators’ attack.

If current levels of carbon dioxide persist or worsen, scientists fear many species of fish will face extinction.

Read more:

  • High CO2 concentrations can turn fish into daredevils (Ars Technica)
  • Replenishment of fish populations is threatened by ocean acidification (PNAS)
Megan Meyer

Megan Meyer is an online and radio producer for WFIU's Arts Bureau and local food program Earth Eats. Megan grew up in South Dakota and later lived in France for 3 years. She was an intern for NPR's Science Desk in the spring of 2009, and joined WFIU in June 2009.

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