New study indicates that a key assumption underlying Atlantic menhaden science may have led to inflated population estimates and allowable catches
Peer-reviewed research finds estimated natural mortality may be nearly twice the rate it should be
WASHINGTON — A new peer-reviewed study raises significant questions about the current Atlantic menhaden stock assessment, finding that a key assumption used to estimate the abundance of menhaden and how much can be harvested each year is set too high.
Investigation of Atlantic Menhaden Mortality Rates, by University of Miami researchers Jerald S. Ault and Jiangang Luo, reexamined one of the largest Atlantic menhaden tagging datasets ever assembled and found that the natural mortality rate used in the current stock assessment is substantially too high.
The 2025 Atlantic menhaden stock assessment uses an annual natural mortality rate of approximately 0.92. An earlier estimate of 1.17 was incorporated into the assessment preceding a major increase in the coastwide menhaden quota in 2022. The new research estimates natural mortality at approximately 0.50.
The difference could have major implications. Natural mortality represents fish assumed to die from causes other than fishing. If substantially fewer menhaden are dying naturally than managers have assumed, fishing could account for a larger share of total mortality, potentially changing estimates of population size, fishing mortality and sustainable harvest levels.
“This could fundamentally change our understanding of the Atlantic menhaden stock,” said Whit Fosburgh, executive director of the Forage Fish Campaign. “Researchers went back to the underlying tagging data and found that one of the fundamental assumptions used to estimate menhaden abundance and allowable harvest may be substantially wrong.”
The researchers found that models producing natural mortality estimates near 0.50 better fit the observed tagging data. Their estimate is also broadly consistent with numerous previous scientific estimates of Atlantic menhaden natural mortality.
“For years, fishermen and coastal communities have warned that we do not have as many menhaden available as the management models suggest,” Fosburgh said. “We have seen bait shortages, the poor condition of striped bass and devastating osprey nesting failures from New York to the Chesapeake Bay. Now peer-reviewed research is calling into question one of the fundamental assumptions behind how this fishery is managed.
“Fisheries Research should review the earlier research in light of these findings and determine whether a correction, retraction or other action is warranted. Fisheries managers also need to fully address this new science before setting future harvest levels. The stakes are too high not to take it seriously.”
Atlantic menhaden are a critical food source for striped bass, bluefish, bluefin tuna, sharks, marine mammals and seabirds, including ospreys. They also support the largest commercial fishery by volume on the U.S. Atlantic Coast. Most commercially harvested menhaden are processed into fish meal, fish oil and related products through the reduction fishery.
The findings come as fisheries managers consider future Atlantic menhaden harvest levels. The study recommends that future stock assessments evaluate natural mortality values centered around 0.50 while accounting for uncertainty, a change that could materially affect the scientific basis used to set future quotas.
The Forage Fish Campaign is calling on fisheries managers to:
Implement a substantial cut to the Atlantic menhaden total allowable catch that ensures at least a 60 percent chance of achieving the ERP target;
Immediately initiate a new Atlantic menhaden stock assessment incorporating the Ault-Luo natural mortality estimate; and
End industrial-scale reduction fishing for Atlantic menhaden while allocating the available quota to traditional bait fisheries.
About the study
Investigation of Atlantic Menhaden Mortality Rates was authored by Jerald S. Ault and Jiangang Luo of the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science and published Sept. 16, 2026, in Fisheries Research.
About the Forage Fish Campaign
The Forage Fish Campaign is a coalition of recreational and commercial fishermen, charter captains, small business owners, conservation advocates and policy leaders working to end industrial-scale forage fishing and protect America's marine ecosystems, coastal economies and fishing traditions.