Biofouled and prey-entangled ropes trigger foraging responses in green turtles.

Area of Science:

• Marine Biology
• Conservation Science
• Animal Behavior

Background:

• Plastic debris poses significant threats to sea turtles through ingestion and entanglement.
• The behavioral mechanisms underlying these interactions are not well understood.

Purpose of the Study:

• To investigate the behavioral responses of green turtles (Chelonia mydas) to various marine debris stimuli.
• To determine how biofouling and associated cues influence sea turtle interactions with plastic debris.

Main Methods:

• Tested five green turtles (one adult, four juveniles) with clean, microfouled, macrofouled, and kelp-entangled ropes, plus kelp alone.
• Quantified biting and leaning behaviors under single- and simultaneous-stimulus conditions over repeated trials.

Main Results:

• Turtles showed strongest biting responses to kelp and kelp-entangled ropes, indicating foraging behavior.
• Biofouling (macrofouled, microfouled) increased attraction to ropes, suggesting incidental plastic ingestion.
• Turtles spent more time leaning on clean ropes, increasing potential entanglement risk.

Conclusions:

• Biofouling on marine debris increases the risk of ingestion by sea turtles.
• Even clean ropes present an entanglement hazard, irrespective of food cues.
• Prioritizing early retrieval of marine debris before biofouling occurs is essential for sea turtle conservation.