Ontogenetic feeding shifts in two thresher shark species in the Galapagos Marine Reserve
Background The morphology and hunting behavior of thresher sharks make them easily distinguishable. These species are distributed across the Tropical Pacific Ocean feeding on squid and small fish. However, ontogenetic changes in their feeding strategies and habitat use are still unknown in this regi...
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2024-12-01
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| author | Camila Arnés-Urgellés Felipe Galván-Magaña Fernando R. Elorriaga-Verplancken Antonio Delgado-Huertas Diego Páez-Rosas |
| author_facet | Camila Arnés-Urgellés Felipe Galván-Magaña Fernando R. Elorriaga-Verplancken Antonio Delgado-Huertas Diego Páez-Rosas |
| author_sort | Camila Arnés-Urgellés |
| collection | DOAJ |
| description | Background The morphology and hunting behavior of thresher sharks make them easily distinguishable. These species are distributed across the Tropical Pacific Ocean feeding on squid and small fish. However, ontogenetic changes in their feeding strategies and habitat use are still unknown in this region. Methods We examined the δ13C and δ15N signatures in vertebral collagen from populations of Alopias pelagicus and Alopias superciliosus inhabiting the Galapagos Marine Reserve, focusing on three maturity stages: neonate, juvenile and adult. The vertebrae samples were taken from the seizure of illegal fishing activities carried out by a foreign fleet within the Galapagos archipelago. A total of thirty-three vertebrae from A. pelagicus and twenty-one from A. superciliosus were analyzed. Results Both species displayed significant differences in their δ15N values (p < 0.001), but not in δ13C (p = 0.230), suggesting a similar habitat use, but different prey consumption. Throughout their ontogeny, A. pelagicus displayed isotopic differences (p < 0.001), where neonates showed lower δ13C values and higher δ15N values compared to juveniles, probably because they still reflect the isotopic signatures of their mothers even after the first year of life. This study highlights trophic differences between both species, accompanied by an ontogenetic variation in A. pelagicus, aspects that allow us to understand the role of these species within the dynamics of the Eastern Tropical Pacific ecosystem. |
| format | Article |
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| institution | DOAJ |
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| language | English |
| publishDate | 2024-12-01 |
| publisher | PeerJ Inc. |
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| spelling | doaj-art-bcc1fa5bdd8d42d0bef3c8ccccf1499c2025-08-20T02:52:42ZengPeerJ Inc.PeerJ2167-83592024-12-0112e1868110.7717/peerj.18681Ontogenetic feeding shifts in two thresher shark species in the Galapagos Marine ReserveCamila Arnés-Urgellés0Felipe Galván-Magaña1Fernando R. Elorriaga-Verplancken2Antonio Delgado-Huertas3Diego Páez-Rosas4Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, Baja California Sur, MexicoCentro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, Baja California Sur, MexicoCentro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, Baja California Sur, MexicoInstituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Universidad de Granada, Granada, Granada, SpainGalapagos Science Center, Universidad San Francisco de Quito, Isla San Cristóbal, Islas Galápagos, EcuadorBackground The morphology and hunting behavior of thresher sharks make them easily distinguishable. These species are distributed across the Tropical Pacific Ocean feeding on squid and small fish. However, ontogenetic changes in their feeding strategies and habitat use are still unknown in this region. Methods We examined the δ13C and δ15N signatures in vertebral collagen from populations of Alopias pelagicus and Alopias superciliosus inhabiting the Galapagos Marine Reserve, focusing on three maturity stages: neonate, juvenile and adult. The vertebrae samples were taken from the seizure of illegal fishing activities carried out by a foreign fleet within the Galapagos archipelago. A total of thirty-three vertebrae from A. pelagicus and twenty-one from A. superciliosus were analyzed. Results Both species displayed significant differences in their δ15N values (p < 0.001), but not in δ13C (p = 0.230), suggesting a similar habitat use, but different prey consumption. Throughout their ontogeny, A. pelagicus displayed isotopic differences (p < 0.001), where neonates showed lower δ13C values and higher δ15N values compared to juveniles, probably because they still reflect the isotopic signatures of their mothers even after the first year of life. This study highlights trophic differences between both species, accompanied by an ontogenetic variation in A. pelagicus, aspects that allow us to understand the role of these species within the dynamics of the Eastern Tropical Pacific ecosystem.https://peerj.com/articles/18681.pdfFeeding strategiesIsotopic nicheOntogenetic changesTropical Eastern PacificThresher sharks |
| spellingShingle | Camila Arnés-Urgellés Felipe Galván-Magaña Fernando R. Elorriaga-Verplancken Antonio Delgado-Huertas Diego Páez-Rosas Ontogenetic feeding shifts in two thresher shark species in the Galapagos Marine Reserve PeerJ Feeding strategies Isotopic niche Ontogenetic changes Tropical Eastern Pacific Thresher sharks |
| title | Ontogenetic feeding shifts in two thresher shark species in the Galapagos Marine Reserve |
| title_full | Ontogenetic feeding shifts in two thresher shark species in the Galapagos Marine Reserve |
| title_fullStr | Ontogenetic feeding shifts in two thresher shark species in the Galapagos Marine Reserve |
| title_full_unstemmed | Ontogenetic feeding shifts in two thresher shark species in the Galapagos Marine Reserve |
| title_short | Ontogenetic feeding shifts in two thresher shark species in the Galapagos Marine Reserve |
| title_sort | ontogenetic feeding shifts in two thresher shark species in the galapagos marine reserve |
| topic | Feeding strategies Isotopic niche Ontogenetic changes Tropical Eastern Pacific Thresher sharks |
| url | https://peerj.com/articles/18681.pdf |
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