This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A steep drop in baby lobsters provided an early warning of the sharp decline in adult lobsters along Maine's midcoast, a new University of Maine study shows. Researchers found that an 80% decline in baby lobsters sampled from 2010 to 2022 was followed by a 70% decline in young lobsters since 2015 and a 50% decline in adults large enough for lobstermen to catch.
The findings trace the losses through successive life stages, showing how fewer baby lobsters preceded fewer adults available to the fishery. The midcoast, which ranges from Brunswick to the Schoodic Peninsula, is where researchers recorded the steepest declines in the Gulf of Maine. Those losses followed a period of growth, when the number of lobsters sampled doubled from the 2000s to the 2010s.
The Gulf of Maine's overall lobster population has declined since the mid-2010s, with implications for a fishery that generated more than $461 million in Maine landings in 2025. UMaine researchers worked with the Maine Department of Marine Resources (DMR) to analyze state surveys that used scuba divers, traps and trawls to sample lobsters at different life stages and depths. Their findings were published in the journal Marine Ecology Progress Series.
Comparing those surveys revealed the pattern of declining numbers from baby to young lobsters to adults. The study classified young lobsters as those with shell lengths of 45 to 83 millimeters (1.8 to 3.3 inches). "Central Maine showed the clearest links among baby, adolescent and adult lobsters across surveys driven by the boom and then decline in lobster abundance in the region tied to warmer water temperatures," said lead researcher Robert Jarrett II, a recent Ph.D. graduate who began the study during his time at UMaine.
"Faster growth there also creates a more consistent signal than in eastern Maine, where slower, variable growth likely makes the signal harder to detect." Downeast Maine experienced a similar decline in the number of baby lobsters sampled since 2010, but a smaller decline among adults. Trends among adolescents varied by survey. Researchers said fewer sampling efforts in Downeast Maine could help explain the differences between the two regions.
Warming waters also have made deeper habitats more suitable for lobsters in midcoast and Downeast Maine. That shift can complicate efforts to track population changes because surveys cover limited areas and habitats, according to researchers. Previous research found that lobster population density declined as lobsters became more dispersed and changed the habitats they occupied.
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