Summer distribution of the Mediterranean sperm whale: insights from the acoustic Accobams survey initiative
The Mediterranean sperm whale population, Physeter macrocephalus, is listed as endangered due to population decline caused by human activities. To mitigate the impact of these activities, accurate knowledge of their distribution and abundance is crucial. During their long dives, sperm whales are not...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-10-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2023.1229682/full |
| _version_ | 1797654455998480384 |
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| author | Clara Lerebourg Oliver Boisseau Vincent Ridoux Vincent Ridoux Auriane Virgili |
| author_facet | Clara Lerebourg Oliver Boisseau Vincent Ridoux Vincent Ridoux Auriane Virgili |
| author_sort | Clara Lerebourg |
| collection | DOAJ |
| description | The Mediterranean sperm whale population, Physeter macrocephalus, is listed as endangered due to population decline caused by human activities. To mitigate the impact of these activities, accurate knowledge of their distribution and abundance is crucial. During their long dives, sperm whales are not available to visual observation, but since they produce sounds when they dive, they are available to acoustic detection. Therefore, we aimed to use towed acoustic data to model their habitat and fill the knowledge gap on Mediterranean sperm whale distribution. Generalised additive models were used to link the number of sperm whales detected acoustically during the ACCOBAMS Survey Initiative in 2018 with different environmental variables integrated over different depth classes, encompassing the depth range used by the species for foraging. Sperm whale distribution was influenced by water temperature at the bottom, eddy kinetic energy between 200 and 600 m, as well as gradients of sea surface temperature and chlorophyll-a concentrations. The abundance of sperm whales was estimated at 2,959 individuals [2,077 - 4,265] in the sampled areas of the Mediterranean Sea. We predicted that sperm whales were mainly distributed in summer along the continental slope of the north-western Mediterranean basin from the Balearic Islands to the Ligurian Sea and off the Algerian coast. They were present throughout the western Mediterranean Sea and in the northern Ionian Sea. In contrast, predicted densities were low in the eastern part of the Mediterranean Sea. The use of acoustic data compensated for the main difficulty in studying sperm whales, the unavailability of animals at the surface during visual observation and the paucity of visual data. We thus encourage more systematic use of passive acoustics to study sperm whale distribution. The model highlighted a higher concentration of sperm whales in the western Mediterranean basin than in the eastern basin in summer, opening up avenues to improve the conservation of this endangered Mediterranean sub-population. |
| first_indexed | 2024-03-11T16:59:43Z |
| format | Article |
| id | doaj.art-d04f72f53ea24c60afcf1decf21d6eaf |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-03-11T16:59:43Z |
| publishDate | 2023-10-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-d04f72f53ea24c60afcf1decf21d6eaf2023-10-20T11:55:53ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452023-10-011010.3389/fmars.2023.12296821229682Summer distribution of the Mediterranean sperm whale: insights from the acoustic Accobams survey initiativeClara Lerebourg0Oliver Boisseau1Vincent Ridoux2Vincent Ridoux3Auriane Virgili4Observatoire Pelagis, Unité d’appui et de recherche (UAR) 3462 Centre national de la recherche scientifique (CNRS) - La Rochelle Université, La Rochelle, FranceMarine Conservation Research (MCR), Kelvedon, United KingdomObservatoire Pelagis, Unité d’appui et de recherche (UAR) 3462 Centre national de la recherche scientifique (CNRS) - La Rochelle Université, La Rochelle, FranceCentre d’Etudes Biologiques de Chizé - La Rochelle, Unité mixte de recherche (UMR) 7372 Centre national de la recherche scientifique (CNRS) - La Rochelle Université, Villiers-en-Bois, FranceObservatoire Pelagis, Unité d’appui et de recherche (UAR) 3462 Centre national de la recherche scientifique (CNRS) - La Rochelle Université, La Rochelle, FranceThe Mediterranean sperm whale population, Physeter macrocephalus, is listed as endangered due to population decline caused by human activities. To mitigate the impact of these activities, accurate knowledge of their distribution and abundance is crucial. During their long dives, sperm whales are not available to visual observation, but since they produce sounds when they dive, they are available to acoustic detection. Therefore, we aimed to use towed acoustic data to model their habitat and fill the knowledge gap on Mediterranean sperm whale distribution. Generalised additive models were used to link the number of sperm whales detected acoustically during the ACCOBAMS Survey Initiative in 2018 with different environmental variables integrated over different depth classes, encompassing the depth range used by the species for foraging. Sperm whale distribution was influenced by water temperature at the bottom, eddy kinetic energy between 200 and 600 m, as well as gradients of sea surface temperature and chlorophyll-a concentrations. The abundance of sperm whales was estimated at 2,959 individuals [2,077 - 4,265] in the sampled areas of the Mediterranean Sea. We predicted that sperm whales were mainly distributed in summer along the continental slope of the north-western Mediterranean basin from the Balearic Islands to the Ligurian Sea and off the Algerian coast. They were present throughout the western Mediterranean Sea and in the northern Ionian Sea. In contrast, predicted densities were low in the eastern part of the Mediterranean Sea. The use of acoustic data compensated for the main difficulty in studying sperm whales, the unavailability of animals at the surface during visual observation and the paucity of visual data. We thus encourage more systematic use of passive acoustics to study sperm whale distribution. The model highlighted a higher concentration of sperm whales in the western Mediterranean basin than in the eastern basin in summer, opening up avenues to improve the conservation of this endangered Mediterranean sub-population.https://www.frontiersin.org/articles/10.3389/fmars.2023.1229682/fullspecies distribution modelMediterranean Seapassive acoustic monitoringsperm whale distributionPhyseter macrocephalus |
| spellingShingle | Clara Lerebourg Oliver Boisseau Vincent Ridoux Vincent Ridoux Auriane Virgili Summer distribution of the Mediterranean sperm whale: insights from the acoustic Accobams survey initiative Frontiers in Marine Science species distribution model Mediterranean Sea passive acoustic monitoring sperm whale distribution Physeter macrocephalus |
| title | Summer distribution of the Mediterranean sperm whale: insights from the acoustic Accobams survey initiative |
| title_full | Summer distribution of the Mediterranean sperm whale: insights from the acoustic Accobams survey initiative |
| title_fullStr | Summer distribution of the Mediterranean sperm whale: insights from the acoustic Accobams survey initiative |
| title_full_unstemmed | Summer distribution of the Mediterranean sperm whale: insights from the acoustic Accobams survey initiative |
| title_short | Summer distribution of the Mediterranean sperm whale: insights from the acoustic Accobams survey initiative |
| title_sort | summer distribution of the mediterranean sperm whale insights from the acoustic accobams survey initiative |
| topic | species distribution model Mediterranean Sea passive acoustic monitoring sperm whale distribution Physeter macrocephalus |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2023.1229682/full |
| work_keys_str_mv | AT claralerebourg summerdistributionofthemediterraneanspermwhaleinsightsfromtheacousticaccobamssurveyinitiative AT oliverboisseau summerdistributionofthemediterraneanspermwhaleinsightsfromtheacousticaccobamssurveyinitiative AT vincentridoux summerdistributionofthemediterraneanspermwhaleinsightsfromtheacousticaccobamssurveyinitiative AT vincentridoux summerdistributionofthemediterraneanspermwhaleinsightsfromtheacousticaccobamssurveyinitiative AT aurianevirgili summerdistributionofthemediterraneanspermwhaleinsightsfromtheacousticaccobamssurveyinitiative |