Crochelet Estelle, Barrier Nicolas, Andrello M., Marsac Francis, Spadone A., Lett Christophe. (2020). Connectivity between seamounts and coastal ecosystems in the Southwestern Indian Ocean. In :
Payne A. (ed.), Roberts M. (ed.), Marsac Francis (ed.), Noyon M. (ed.), Ternon Jean-François (ed.). Bio-physical coupling around three shallow seamounts in the South Western Indian Ocean, with regional comparisons based on modelling, remote sensing and observational studies. Deep-Sea Research Part II : Topical Studies in Oceanography, 176 (No spécial), art. 104774 [18 p.]. ISSN 0967-0645.
Titre du document
Connectivity between seamounts and coastal ecosystems in the Southwestern Indian Ocean
Année de publication
2020
Auteurs
Crochelet Estelle, Barrier Nicolas, Andrello M., Marsac Francis, Spadone A., Lett Christophe
In
Payne A. (ed.), Roberts M. (ed.), Marsac Francis (ed.), Noyon M. (ed.), Ternon Jean-François (ed.), Bio-physical coupling around three shallow seamounts in the South Western Indian Ocean, with regional comparisons based on modelling, remote sensing and observational studies
Source
Deep-Sea Research Part II : Topical Studies in Oceanography, 2020,
176 (No spécial), art. 104774 [18 p.] ISSN 0967-0645
Understanding larval connectivity patterns is critical for marine spatial planning, particularly for designing marine protected areas and managing fisheries. Patterns of larval dispersal and connectivity can be inferred from numerical transport models at large spatial and temporal scales. We assess model-based connectivity patterns between seamounts of the Southwestern Indian Ocean (SWIO) and the coastal ecosystems of Mauritius, La Reunion, Madagascar, Mozambique and South Africa, with emphasis on three shallow seamounts (La Perouse [LP], MAD-Ridge [MR] and Walters Shoal [WS]). Using drifter trajectory and a Lagrangian model of ichthyo-plankton dispersal, we show that larvae can undertake very long dispersion, with larval distances increasing with pelagic larval duration (PLD). There are three groups of greater connectivity: the region between the eastern coast of Madagascar, Mauritius and La Reunion islands; the seamounts of the South West Indian Ridge; and the pair formed by WS and a nearby un-named seamount. Connectivity between these three groups is evident only for the longest PLD examined (360 d). Connectivity from seamounts to coastal ecosystems is weak, with a maximum of 2% of larvae originating from seamounts reaching coastal ecosystems. Local retention at the three focal seamounts (LP, MR and WS) peaks at about 11% for the shortest PLD considered (15 d) at the most retentive seamount (WS) and decreases sharply with increasing PLD. Information on PLD and age of larvae collected at MR and LP are used to assess their putative origin. These larvae are likely self-recruits but it is also plausible that they immigrate from nearby coastal sites, i.e. the southern coast of Madagascar for MR and the islands of La Reunion and Mauritius for LP.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Limnologie / Océanographie : généralités [030]
;
Limnologie biologique / Océanographie biologique [034]
;
Ecologie, systèmes aquatiques [036]
Description Géographique
OCEAN INDIEN ; MADAGASCAR ; REUNION ; MAURICE ; MOZAMBIQUE ; AFRIQUE DU SUD
Localisation
Fonds IRD [F B010079444]
Identifiant IRD
fdi:010079444
