image: Pictured is a zebrafish. view more
Credit: Image credit: Per Harald Olsen (photographer).
A study measures the evolution of upper thermal tolerance in zebrafish over six generations. Upper thermal tolerance is critical for vertebrate survival as heat waves from climate change continue to intensify. However, whether upper thermal tolerance in fish can evolve quickly enough in response to increasing temperatures is unclear. Rachael Morgan and colleagues examined how more than 20,000 zebrafish over six generations evolved higher thermal tolerance in an artificial selection experiment. At each generation, the authors artificially selected and bred fish that naturally exhibited high upper thermal tolerance to test if evolution of thermal tolerance could occur over a few generations. Upper thermal tolerance evolved over the course of six generations; however, tolerance only increased at approximately 0.04°C per generation, which is unlikely to keep at the pace of rising water temperatures for several fish populations. The findings suggest that fish may have a hard limit of upper thermal tolerance that restricts evolution. In addition, it may be difficult for tropical fish living close to their thermal limits to adapt to waters that are rapidly warming from climate change, according to the authors.
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Article #20-11419: "Low potential for evolutionary rescue from climate change in a tropical fish," by Rachael Morgan, Mette H. Finnøen, Henrik Jensen, Christophe Pélabon, and Fredrik Jutfelt.
MEDIA CONTACT: Rachael Morgan, Norwegian University of Science and Technology, Trondheim, NORWAY/University of Glasgow, UNITED KINGDOM; tel: +44-7377209906; e-mail: <rachael.morgan@glasgow.ac.uk>; Fredrik Jutfelt, Norwegian University of Science and Technology, Trondheim, NORWAY; tel: +47-91305418; e-mail: <fredrik.jutfelt@ntnu.no>
Journal
Proceedings of the National Academy of Sciences