March 18, 2026 — A severe and prolonged U.S. drought in the late 1980s played a central role in one of the largest fisheries declines ever recorded in the Gulf of Mexico, according to a new study published in Nature Communications.
The research, led by scientists at the University of Haifa and co-authored by Ben Kirtman, a climate scientist and dean of the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science, found that drought-driven reductions in Mississippi River flow sharply limited nutrient delivery to coastal waters.
“Our findings show that the fisheries collapse was not driven by fishing pressure alone,” said Igal Berenshtein, head of the Marine Ecology and Ocean Health Laboratory at the University of Haifa, and the study’s lead author. “The prolonged drought reduced river discharge and nutrient input to the Gulf, weakening phytoplankton production and primary productivity at the base of the food web. That disruption cascaded through the ecosystem, ultimately reducing fish biomass and fisheries yields.”
The study documented a roughly 42 percent drop in total fish biomass and a 34 percent decline in fisheries catch following the drought period. Nearly 90 percent of species groups examined showed decreases in biomass.