CNN's John Sutter in Atlanta, Yoko Wakatsuki and Alex Zolbert in Tokyo, Diego Lage in Hong Kong and Laura Mackenzie in London contributed to this report.
Some commentators do not discount the possibility that Carlos Lage, the de facto prime minister who runs the economy, might be named as the new president.
"No previous study has allowed the evaluation of the impact of hatchery stocking activities on Penobscot river Salmon, " said Chris Lage, a graduate student working with Kornfield on the study.