Embryonic buoyancy control as a mechanism of ultraviolet radiation avoidance

Christina Pasparakis, Yadong Wang, John D. Stieglitz, Daniel D. Benetti, Martin Grosell

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Pelagic fish have long been presumed to produce buoyant embryos which float and hatch at or near surface waters. Due to their transparency and rapid development, mahi embryos are thought to be especially vulnerable to stressors occurring in surface waters, such as ultraviolet radiation (UVR) and increased temperatures. In the present study, we suggest a possibly critical mechanism of UVR avoidance by pelagic fish embryos. Specifically, we provide evidence that mahi embryos are able to sense UVR and may alter buoyancy as a means of reducing exposure to the most harmful stressors occurring in the upper layers of the water column. Further, once the UVR exposure was terminated, embryos displayed fast recovery of positive buoyancy indicating this response is rapidly dynamic and not pathological. The mechanism behind buoyancy control is not known, but evidence from the current study suggests that ammonia sequestration, as seen in multiple other fish species, is not the primary control mechanism employed by embryonic mahi. Finally, expression of antioxidant and UV repair enzymes were investigated to elucidate possible involvement in observed buoyancy changes and to explore alternative methods of repairing UVR damage.

Original languageEnglish (US)
Pages (from-to)3070-3078
Number of pages9
JournalScience of the Total Environment
StatePublished - Feb 15 2019


  • Antioxidant enzymes
  • Mahi-mahi
  • Photolyase
  • Surface waters
  • UV repair

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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