The swimming performance of popular fish Mahi-Mahi has reduced by 37 percent, according to a University of Miami study. The impaired performance is particularly observed in those fish who were exposed to oil from the 2010 BP Deepwater Horizon spill as infants.

The researchers said that the findings highlight the lethal effects of crude oil on ecologically and commercially important fish, populous in northern Gulf of Mexico.

"What our study shows is that even a relatively brief, low-level exposure to oil harms the swimming capabilities of mahi-mahi, and likely other large pelagic fish, during the early life stages," said Edward Mager, Rosenstiel School postdoctoral associate and lead author of the study, in a press release. "If you harm a fish's ability to swim you also harm its ability to perform actions that are critical for survival, such as catching prey and evading predation."

For the study, researchers exposed two groups of larvae and juvenile mahi-mahi to Deepwater Horizon crude oil to simulate environmental conditions during the 2010 Deepwater Horizon oil spill. The oil used in the study was collected on July 29, 2010 from surface slicks during the Deepwater Horizon episode.

Among the two groups, one group was exposed for 48 hours during the embryonic-larval stage and then raised in clean seawater to the juvenile stage; while the other group was raised in clean seawater to the juvenile stage and then exposed to oil for 24 hours.

On the other hand, a control group was exposed to clean seawater.

The researchers found that the 48-hour embryonic-larval exposure group experienced a 37 percent reduction in swimming velocity as juveniles, while 24-hour juvenile exposure groups recorded a 22 percent decrease in swimming velocity.

"The study demonstrates how careful measurements of physiological performance may reveal subtle, yet highly significant impacts of environmental contamination," said Martin Grosell, Maytag chair and professor of Ichthyology at the Rosenstiel School and a co-author of the study.