Functional responses of North Atlantic fish eggs to increasing temperature

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Temperature increase associated with global climate change can be expected to directly influence the spawning success of fish species. We investigated and compared responses of development time and survival of fish eggs from 32 species and populations in the North Atlantic to different temperatures in order to assess and compare potential consequences of global warming for these species. The response of development time to temperature increase exhibited a decreasing trend. The similar slopes of regression lines relating development time and temperature indicate similar sensitivity to temperature changes. Across-species differences were mainly driven by intercept values, indicating up to 8-fold differences in development time at given temperature. Moreover, the sensitivity of survival of eggs from different species to temperature increase differed among species, indicating different vulnerabilities. The results quantify physiological effects of temperature on the eggs and show that such effects are major factors leading to a close correspondence between the physiological optimal temperature for survival and observed temperature at spawning sites. Temperature during egg development appears to be a key evolutionary force affecting spawning time and location.