The feeding habit of sea turtles influences their reaction to artificial marine debris.
Ingestion of artificial debris is considered as a significant stress for wildlife including sea turtles. To investigate how turtles react to artificial debris under natural conditions, we deployed animal-borne video cameras on loggerhead and green turtles in addition to feces and gut contents analyses from 2007 to 2015. Frequency of occurrences of artificial debris in feces and gut contents collected from loggerhead turtles were 35.7% (10/28) and 84.6% (11/13), respectively. Artificial debris appeared in all green turtles in feces (25/25) and gut contents (10/10), and green turtles ingested more debris (feces; 15.8 ± 33.4 g, gut; 39.8 ± 51.2 g) than loggerhead turtles (feces; 1.6 ± 3.7 g, gut; 9.7 ± 15.0 g). In the video records (60 and 52.5 hours from 10 loggerhead and 6 green turtles, respectively), turtles encountered 46 artificial debris and ingested 23 of them. The encounter-ingestion ratio of artificial debris in green turtles (61.8%) was significantly higher than that in loggerhead turtles (16.7%). Loggerhead turtles frequently fed on gelatinous prey (78/84), however, green turtles mainly fed marine algae (156/210), and partly consumed gelatinous prey (10/210). Turtles seemed to confuse solo drifting debris with their diet, and omnivorous green turtles were more attracted by artificial debris.
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, 277-8564, Japan.
Takuya
T
Fukuoka
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, 277-8564, Japan.
Misaki
M
Yamane
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, 277-8564, Japan.
Chihiro
C
Kinoshita
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, 277-8564, Japan.
Tomoko
T
Narazaki
National Geographic Remote Imaging, 1145 17th Street NW Washington, D.C., 20036, United States of America.
Greg J
GJ
Marshall
National Geographic Remote Imaging, 1145 17th Street NW Washington, D.C., 20036, United States of America.
Kyler J
KJ
Abernathy
Japan Marine Science Foundation, 1-1-1 Ikenohata, Taito-ku, Tokyo, 110-0008, Japan.
Nobuyuki
N
Miyazaki
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, 277-8564, Japan.
Katsufumi
K
Sato
D000818:Animals; D004435:Eating; D005243:Feces / Q000737:chemistry*; D005247:Feeding Behavior / Q000502:physiology* / Q000523:psychology*; D014426:Turtles / Q000502:physiology*; D014866:Waste Products; D014873:Water Pollutants
D014866:Waste Products; D014873:Water Pollutants