Modeling the drift of European (Anguilla anguilla) and American (Anguilla rostrata) eel larvae during the year of spawning
The distribution of the leptocephalus larvae of European (Anguilla anguilla) and American (Anguilla rostrata) eels collected during recent Sargasso Sea surveys was used to model larval drift. The drift trajectories of individual larva were back-calculated to the estimated time of spawning, using cur...
| Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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| Main Authors: | , , , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | https://doi.org/10.1139/cjfas-2016-0256 https://www.openagrar.de/receive/openagrar_mods_00036167 https://www.openagrar.de/servlets/MCRFileNodeServlet/openagrar_derivate_00010315/dn058657.pdf |
| Summary: | The distribution of the leptocephalus larvae of European (Anguilla anguilla) and American (Anguilla rostrata) eels collected during recent Sargasso Sea surveys was used to model larval drift. The drift trajectories of individual larva were back-calculated to the estimated time of spawning, using current data from two global oceanographic assimilation models. The results of both models give the same overall result; widespread spawning extended in time from December to March. The drift was also calculated forwards for approximately 1 year. The forward drift modelling showed that most leptocephali remained in the area south of the Subtropical Frontal Zone. One conclusion is that the majority of leptocephali remain trapped and possibly die in the retention area. A small proportion of leptocephali are entrained into the Gulf Stream system. An implication is that the spawning success may be highly sensitive to oceanographic and climatic factors that alter the dispersion of leptocephali out from the retention area. An alternative interpretation is that the surveys were made too late after the peak spawning period and that the core spawning area was missed. La répartition de leptocéphales d’anguilles européennes (Anguilla anguilla) et américaines (Anguilla rostrata) prélevés durant de récents relevés dans la mer des Sargasses a été utilisée pour modéliser la dérive des larves. Les trajectoires de dérive de leptocéphales individuels ont été rétrocalculées jusqu’au moment estimé du frai en utilisant des données sur les courants issues de deux modèles d’assimilation de données océanographiques planétaires. Les résultats des deux modèles donnent le même résultat global, soit un frai répandu dans l’espace et réparti dans le temps de décembre a` mars. La dérive a également été calculée prospectivement pour environ 1 année. La modélisation prospective de la dérive démontre que la plupart des leptocéphales sont demeurés dans la région au sud de la zone frontale subtropicale. Il est conclu que la majorité des leptocéphales ... |
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