Loggerhead Turtles (Caretta caretta) in the California Current: Abundance, Distribution, and Anomalous Warming of the North Pacific
Environmental variability affects distributions of marine predators in time and space. With expected changes in the ocean climate, understanding the relationship between species distributions and the environment is essential for developing successful management regulations. Here we provide informati...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2018-12-01
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| Series: | Frontiers in Marine Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/article/10.3389/fmars.2018.00452/full |
| _version_ | 1811260251889991680 |
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| author | Tomoharu Eguchi Sam McClatchie Cara Wilson Scott R. Benson Scott R. Benson Robin A. LeRoux Jeffrey A. Seminoff |
| author_facet | Tomoharu Eguchi Sam McClatchie Cara Wilson Scott R. Benson Scott R. Benson Robin A. LeRoux Jeffrey A. Seminoff |
| author_sort | Tomoharu Eguchi |
| collection | DOAJ |
| description | Environmental variability affects distributions of marine predators in time and space. With expected changes in the ocean climate, understanding the relationship between species distributions and the environment is essential for developing successful management regulations. Here we provide information on an ephemeral but important habitat for North Pacific loggerhead turtles (Caretta caretta) at the northeastern edge of their range. North Pacific loggerhead turtles nest on Japanese beaches and juveniles disperse throughout the North Pacific; some remain in the high seas of the central North Pacific whereas others transition to the eastern Pacific and forage near Baja California, Mexico. Loggerheads have also been reported along the United States west coast, with the majority of sightings off southern California. Here we describe their demography and distribution in the area, based on two aerial surveys (2011, 2015), at-sea sightings, and stranding records. Our aerial survey during fall 2015 determined density, abundance, and distribution of loggerheads in the area, when anomalous warming of the North Pacific and El Niño conditions co-occurred. Using line-transect analysis, we estimated ca. 15,000 loggerheads at the sea surface (CV = 21%) and more than 70,000 loggerheads when accounting for those that were submerged and not available for detection. Our survey during fall 2011 resulted in no loggerhead sightings, demonstrating a high variability of loggerhead density in the region. We encourage further research on loggerheads in the area to determine the mechanisms that promote their occurrence. These studies should include regular surveys throughout their foraging areas along the west coast of the North America as well as assessments of prey availability and local oceanographic conditions. |
| first_indexed | 2024-04-12T18:44:39Z |
| format | Article |
| id | doaj.art-b30b7e9cbd0b43ebb7f6a0f242fff572 |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-04-12T18:44:39Z |
| publishDate | 2018-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-b30b7e9cbd0b43ebb7f6a0f242fff5722022-12-22T03:20:40ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452018-12-01510.3389/fmars.2018.00452409133Loggerhead Turtles (Caretta caretta) in the California Current: Abundance, Distribution, and Anomalous Warming of the North PacificTomoharu Eguchi0Sam McClatchie1Cara Wilson2Scott R. Benson3Scott R. Benson4Robin A. LeRoux5Jeffrey A. Seminoff6Marine Mammal & Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, La Jolla, CA, United StatesFisheries Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service, La Jolla, CA, United StatesEnvironmental Research Division, Southwest Fisheries Science Center, National Marine Fisheries Service, Monterey, CA, United StatesMarine Mammal & Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, Moss Landing, CA, United StatesMoss Landing Marine Laboratories, Moss Landing, CA, United StatesMarine Mammal & Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, La Jolla, CA, United StatesMarine Mammal & Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, La Jolla, CA, United StatesEnvironmental variability affects distributions of marine predators in time and space. With expected changes in the ocean climate, understanding the relationship between species distributions and the environment is essential for developing successful management regulations. Here we provide information on an ephemeral but important habitat for North Pacific loggerhead turtles (Caretta caretta) at the northeastern edge of their range. North Pacific loggerhead turtles nest on Japanese beaches and juveniles disperse throughout the North Pacific; some remain in the high seas of the central North Pacific whereas others transition to the eastern Pacific and forage near Baja California, Mexico. Loggerheads have also been reported along the United States west coast, with the majority of sightings off southern California. Here we describe their demography and distribution in the area, based on two aerial surveys (2011, 2015), at-sea sightings, and stranding records. Our aerial survey during fall 2015 determined density, abundance, and distribution of loggerheads in the area, when anomalous warming of the North Pacific and El Niño conditions co-occurred. Using line-transect analysis, we estimated ca. 15,000 loggerheads at the sea surface (CV = 21%) and more than 70,000 loggerheads when accounting for those that were submerged and not available for detection. Our survey during fall 2011 resulted in no loggerhead sightings, demonstrating a high variability of loggerhead density in the region. We encourage further research on loggerheads in the area to determine the mechanisms that promote their occurrence. These studies should include regular surveys throughout their foraging areas along the west coast of the North America as well as assessments of prey availability and local oceanographic conditions.https://www.frontiersin.org/article/10.3389/fmars.2018.00452/fulldistance samplingEastern PacificEl Niño Southern Oscillationline transectstranding |
| spellingShingle | Tomoharu Eguchi Sam McClatchie Cara Wilson Scott R. Benson Scott R. Benson Robin A. LeRoux Jeffrey A. Seminoff Loggerhead Turtles (Caretta caretta) in the California Current: Abundance, Distribution, and Anomalous Warming of the North Pacific Frontiers in Marine Science distance sampling Eastern Pacific El Niño Southern Oscillation line transect stranding |
| title | Loggerhead Turtles (Caretta caretta) in the California Current: Abundance, Distribution, and Anomalous Warming of the North Pacific |
| title_full | Loggerhead Turtles (Caretta caretta) in the California Current: Abundance, Distribution, and Anomalous Warming of the North Pacific |
| title_fullStr | Loggerhead Turtles (Caretta caretta) in the California Current: Abundance, Distribution, and Anomalous Warming of the North Pacific |
| title_full_unstemmed | Loggerhead Turtles (Caretta caretta) in the California Current: Abundance, Distribution, and Anomalous Warming of the North Pacific |
| title_short | Loggerhead Turtles (Caretta caretta) in the California Current: Abundance, Distribution, and Anomalous Warming of the North Pacific |
| title_sort | loggerhead turtles caretta caretta in the california current abundance distribution and anomalous warming of the north pacific |
| topic | distance sampling Eastern Pacific El Niño Southern Oscillation line transect stranding |
| url | https://www.frontiersin.org/article/10.3389/fmars.2018.00452/full |
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