Warming oceans could slow reef fish down, threaten survival

Warming may make large reef fish feel it's too hot to swim, threatening survival activities including feeding and finding mates, Australian researchers say. A team of researchers from the ARC Center of Excellence for Coral Reef Studies at James Cook University has reported that ocean warming may lead to some reef fish becoming lethargic, spending more time resting on the bottom and less time swimming in search for food or reproductive opportunities. "The loss of swimming performance and reduced ability to maintain important activities, like moving to a spawning site to reproduce, could have major implications for the future distribution and abundance of these species," researcher Jacob Johansen said in a center release Wednesday. The study of the impact of global warming on a commercially important fish species, coral trout, showed that even when individuals do muster up enough energy to swim around, they did so at much slower rate likely to directly impact their ability to catch food, or visit spawning sites, the scientists said. Changes to activity patterns and swimming speeds "may directly influence where we will find these species in the future and how many we are able to fish sustainably," researcher Morgan Pratchett said.