Listen Up

Ocean acidification could improve some fish’s hearing, scientists report in Proceedings of the National Academy of Sciences.

The team measured ear bones called otoliths in cobia, a type of tropical fish. Two groups of fish were raised in acidified water, comparable to what scientists expect in the oceans by 2100 or 2300 as a result of climate change. The otoliths of fish exposed to the most acidified conditions were as much as 49 percent bigger, 58 percent heavier, and 6 percent denser than those of control fish, the researchers found.

Those changes could extend the cobia’s hearing range by roughly 50 percent, according to the study. But it’s not clear whether a fish’s chances of survival will increase as a result. Improved hearing could help fish detect cues that are important for navigating their environment or eluding predators, but the increase in background noise might also drown out those sounds. Roberta Kwok | 23 April 2013

Source: Bignami, S. et al. 2013. Ocean acidification alters the otoliths of a pantropical fish species with implications for sensory function. Proceedings of the National Academy of Sciences doi: 10.1073/pnas.1301365110.

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