Fish can adjust to warmer ocean temperatures, but heat waves can still kill them, a team of researchers from Sweden, Norway and Australia reports in an article published this week in Nature Communications. "A species might adapt and grow well (in warmer waters) but once you get strong heat spells, the water temperature might reach lethal temperatures and kill them," said Fredrik Jutfelt, an associate professor in biology at the Norwegian University of Science and Technology who was senior author of the study.Jutfelt and his colleagues studied European perch that live in a unique enclosed basin of warm water off the Swedish coast. The man-made basin, called the Forsmark Biotest Enclosure, was created three decades ago as a 1-km2 open-air laboratory by piping warm water from the nearby Forsmark nuclear power plant into an enclosed basin.