Behavioral responses of captive-bred post-hatchling and juvenile sea turtles to different colors of single-use plastic film.

Sea turtles face significant threats from plastic ingestion, yet their behavioral responses to plastics remain poorly understood. We observed the responses of eight 4-year-old juvenile and twenty-seven 10-week-old post-hatchling captive-bred hawksbill turtles (Eretmochelys imbricata) to single-use plastic films with different colors and toughness, types commonly found in the digestive tracts of wild turtle carcasses. Each turtle’s biting or touching toward the introduced plastic item was recorded. Juveniles frequently bit or touched light-colored (transparent or white) packaging and plastic bags, black plastic bags, and yellow snack packaging, but ignored blue bottle labels. Their preference may reflect sensitivity to light colors (e.g., white), and to softer materials (i.e., plastic bags over packaging). These findings align with previous studies on sea turtle responses to undyed or dyed jellyfish (Rhopilema esculentum), and plastics in the digestive tracts of carcasses. However, post-hatchlings showed no significant differences in responses, likely due to limited prey recognition at an early life stage. This study represents the first assessment of sea turtle behavioral responses to single-use plastics as visual cues. While post-hatchlings may ingest plastic randomly, older turtles are vulnerable to light-colored, soft plastics, putting sea turtles at risk of plastic ingestion throughout all life stages. Action is needed for targeted management of high-risk debris.