Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water.
Identifying characteristics of foraging activity is fundamental to understanding an animals' lifestyle and foraging ecology. Despite its importance, monitoring the foraging activities of marine animals is difficult because direct observation is rarely possible. In this study, we use an animal-b...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2013-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3680403?pdf=render |
| _version_ | 1818036764894298112 |
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| author | Tomoko Narazaki Katsufumi Sato Kyler J Abernathy Greg J Marshall Nobuyuki Miyazaki |
| author_facet | Tomoko Narazaki Katsufumi Sato Kyler J Abernathy Greg J Marshall Nobuyuki Miyazaki |
| author_sort | Tomoko Narazaki |
| collection | DOAJ |
| description | Identifying characteristics of foraging activity is fundamental to understanding an animals' lifestyle and foraging ecology. Despite its importance, monitoring the foraging activities of marine animals is difficult because direct observation is rarely possible. In this study, we use an animal-borne imaging system and three-dimensional data logger simultaneously to observe the foraging behaviour of large juvenile and adult sized loggerhead turtles (Caretta caretta) in their natural environment. Video recordings showed that the turtles foraged on gelatinous prey while swimming in mid-water (i.e., defined as epipelagic water column deeper than 1 m in this study). By linking video and 3D data, we found that mid-water foraging events share the common feature of a marked deceleration phase associated with the capture and handling of the sluggish prey. Analysis of high-resolution 3D movements during mid-water foraging events, including presumptive events extracted from 3D data using deceleration in swim speed as a proxy for foraging (detection rate = 0.67), showed that turtles swam straight toward prey in 171 events (i.e., turning point absent) but made a single turn toward the prey an average of 5.7±6.0 m before reaching the prey in 229 events (i.e., turning point present). Foraging events with a turning point tended to occur during the daytime, suggesting that turtles primarily used visual cues to locate prey. In addition, an incident of a turtle encountering a plastic bag while swimming in mid-water was recorded. The fact that the turtle's movements while approaching the plastic bag were analogous to those of a true foraging event, having a turning point and deceleration phase, also support the use of vision in mid-water foraging. Our study shows that integrated video and high-resolution 3D data analysis provides unique opportunities to understand foraging behaviours in the context of the sensory ecology involved in prey location. |
| first_indexed | 2024-12-10T07:16:08Z |
| format | Article |
| id | doaj.art-b6377b3adeb54c97b095e96f4be5c23c |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-10T07:16:08Z |
| publishDate | 2013-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-b6377b3adeb54c97b095e96f4be5c23c2022-12-22T01:57:56ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0186e6604310.1371/journal.pone.0066043Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water.Tomoko NarazakiKatsufumi SatoKyler J AbernathyGreg J MarshallNobuyuki MiyazakiIdentifying characteristics of foraging activity is fundamental to understanding an animals' lifestyle and foraging ecology. Despite its importance, monitoring the foraging activities of marine animals is difficult because direct observation is rarely possible. In this study, we use an animal-borne imaging system and three-dimensional data logger simultaneously to observe the foraging behaviour of large juvenile and adult sized loggerhead turtles (Caretta caretta) in their natural environment. Video recordings showed that the turtles foraged on gelatinous prey while swimming in mid-water (i.e., defined as epipelagic water column deeper than 1 m in this study). By linking video and 3D data, we found that mid-water foraging events share the common feature of a marked deceleration phase associated with the capture and handling of the sluggish prey. Analysis of high-resolution 3D movements during mid-water foraging events, including presumptive events extracted from 3D data using deceleration in swim speed as a proxy for foraging (detection rate = 0.67), showed that turtles swam straight toward prey in 171 events (i.e., turning point absent) but made a single turn toward the prey an average of 5.7±6.0 m before reaching the prey in 229 events (i.e., turning point present). Foraging events with a turning point tended to occur during the daytime, suggesting that turtles primarily used visual cues to locate prey. In addition, an incident of a turtle encountering a plastic bag while swimming in mid-water was recorded. The fact that the turtle's movements while approaching the plastic bag were analogous to those of a true foraging event, having a turning point and deceleration phase, also support the use of vision in mid-water foraging. Our study shows that integrated video and high-resolution 3D data analysis provides unique opportunities to understand foraging behaviours in the context of the sensory ecology involved in prey location.http://europepmc.org/articles/PMC3680403?pdf=render |
| spellingShingle | Tomoko Narazaki Katsufumi Sato Kyler J Abernathy Greg J Marshall Nobuyuki Miyazaki Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water. PLoS ONE |
| title | Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water. |
| title_full | Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water. |
| title_fullStr | Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water. |
| title_full_unstemmed | Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water. |
| title_short | Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water. |
| title_sort | loggerhead turtles caretta caretta use vision to forage on gelatinous prey in mid water |
| url | http://europepmc.org/articles/PMC3680403?pdf=render |
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