Swimming crab trapped in plastic bottle survived two months on the ocean

by Hiroshima University
July 2, 2026

Marine plastic pollution is a major and well-known component of pollution in the oceans. Examples of the impacts of plastic pollution on ocean life serve as some of the most evocative demonstrations of the severe negative impacts of plastic pollution on marine animals. Images of seals and seabirds entangled in fishing nets, and sea turtles eating plastic bags are often used for this purpose.

Researchers at Hiroshima University discovered a crab trapped in a high-density polyethylene (HDPE) Shaoxing wine bottle floating on the surface of sea off Okinawa, Japan. Investigations into how the crab came to be trapped and how it managed to survive highlight that the dangers of plastic pollution extend even to smaller marine animals. 

Their findings were published in the journal Ecosphere on April 3, 2026.

“During juvenile fish surveys in offshore waters, we happened to encounter a floating plastic bottle approximately 500 m off Sesoko Island, Okinawa, Japan, with many juvenile fish associated with it,” say study authors Hajime Sato and Yoichi Sakai. Sato, first and corresponding author of the study, was a doctoral student under Sakai at the time of the study (now a postdoctoral research fellow at the Okinawa Institute of Science and Technology (OIST) in Okinawa). Sakai is professor at Hiroshima University’s Graduate School of Integrated Sciences for Life. “[To our surprise], a large live swimming crab, Portunus sanguinolentus, was trapped inside the bottle. The crab was clearly larger than the opening of the bottle!”

Keep reading: https://www.hiroshima-u.ac.jp/en/news/98552

Read the Ecosphere paper: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.70609