Antarctic Fish Development and Climate: Heat Plus Carbon

Developing from embryo to grown in elevated carbon dioxide and a higher ocean-water temperature isn't easy for at least one south-pole fish, the Antarctic Dragonfish, say researchers from University of California, Davis and San Francisco State University who recently published a report in the journal Conservation Physiology.

That is, climate change has a significant effect on the survival and development of the Gymnodraco acuticeps. Also, because this fish's embryonic development takes longer than many species (up to 10 months), it is particularly vulnerable to a change in conditions, according to a release.

The team's research measured the dragonfish embryo's survival and metabolism over time in two different temperatures and three levels of pressure exerted by carbon dioxide on the fish's arterial blood (pCO2), over three weeks, the release said.

They learned that the applied changes significantly altered the fish's physiology and development. One of the article's authors, SFSU Assistant Professor Anne Todgham, explained in the release that "temperature will probably be the main driver of change, but increases in pCO2 will also alter embryonic physiology, with responses dependent on water temperature." 

They learned that the dragonfish embryos were more likely to die when higher temperatures were combined with increased pCO2 over the three-week experiment, the release said.

This suggests, then, that single stressors may not be enough to predict the early development of fish, because the negative effects of increased pCO2 may only appear at higher temperatures. Also, fish may differ from other invertebrate embryos in marine environments in regard to pCO2 response, noted the release.

These unique findings show that single stressors alone may not be sufficient to predict the effects on early development of fish, as the negative effects of increased pCO2 may only manifest at increased temperatures. They also show that fish may differ from other marine invertebrate embryos in how they respond to pCO2, the release said.

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