Florida, USA – Plastic pollution is quietly reshaping marine ecosystems. A new study by Florida Atlantic University shows that oleamide, a chemical leached from common plastics, disrupts predator-prey behavior in South Florida waters.

Researchers studied Octopus vulgaris and its interactions with hermit crabs, free-living crabs, snails, and clams in controlled aquariums. More than 31,500 observations tracked predation and non-consumptive interactions.

“Many species rely on chemical information to detect food, assess predation risk, and balance the tradeoffs between foraging and staying safe,” said Michael W. McCoy, Ph.D., senior author. “When oleamide entered the system, that chemical communication appeared to break down. Crustacean prey reduced their predator-avoidance behaviors, even as the octopus became more exploratory and increased their interactions – especially grasps.”

Before exposure, octopuses preferred crustaceans. During exposure, hermit crab selection dropped while free-living crab interactions increased. These changes persisted even after oleamide was removed, with non-consumptive interactions remaining high.

Oleamide mimics natural cues like oleic acid, misleading prey into taking more risks and prompting octopuses to explore more. The result is subtle but far-reaching behavioral shifts that may alter feeding dynamics, species distribution, and ecosystem balance.

“These changes in predator-prey interactions could have far-reaching effects on marine ecosystems,” said Madelyn A. Hair, first author. “Oleamide leaching from plastics may reshape the distribution and abundance of resources and influence interaction rates across multiple species.”

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