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Auteur Crochelet, E.; Barrier, N.; Andrello, M.; Marsac, F.; Spadone, A.; Lett, C.
Titre Connectivity between seamounts and coastal ecosystems in the Southwestern Indian Ocean Type Article scientifique
Année 2020 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.
Volume 176 Numéro Pages 104774
Mots-Clés behavior; Biophysical model; Connectivity; conservation; coral-reef fishes; Ichthyop; Lagrangian modelling; larvae dispersal; Larval drift; Larval duration; local retention; madagascar; marine populations; model; population connectivity; recruitment; Seamounts; Southwestern indian ocean; Surface drifters
Résumé 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 Pemuse [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.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0967-0645 ISBN Médium
Région Expédition Conférence
Notes WOS:000556810400003 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2840
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Auteur Kolasinski, J.; Frouin, P.; Sallon, A.; Rogers, K.; Bruggemann, H.J.; Potier, M.
Titre Feeding ecology and ontogenetic dietary shift of yellowstripe goatfish Mulloidichthys flavolineatus (Mullidae) at Reunion Island, SW Indian Ocean Type Article scientifique
Année 2009 Publication Revue Abrégée Marine Ecology – Progress Series
Volume 386 Numéro Pages 181-195
Mots-Clés isotopes; Mixing model; Ontogenetic diet shift; Southwestern Indian Ocean; Stable; Stomach contents; Yellowstripe goatfish
Résumé We analyzed stomach contents and muscle isotopic composition (delta C-13, delta N-15) of yellowstripe goatfish Mulloidichthys flavolineatus from a coral reef to investigate size-related dietary changes and resource or habitat partitioning. Juveniles (< 12 cm total length [TL]), young adults (12 <= TL < 17 cm) and adults (>= 17 cm TL) showed a high diet overlap, especially between juveniles and young adults. According to stomach contents analysis, M. flavolineatus widens its prey spectrum with increasing size from a common prey pool that includes polychaetes, tanaids and harpacticoid copepods. We observed a significant increase in delta C-13 values (from -17.1 +/- 0.5 parts per thousand for juveniles to -10.7 +/- 0.8 parts per thousand for adults), which were correlated to fish size. Adults (delta N-15 mean of 11.1 +/- 1.8 parts per thousand) were one trophic level above juveniles and young adults (7.7 +/- 0.5 and 7.4 +/- 0.5 parts per thousand, respectively). These patterns of isotopic changes confirmed ontogenetic dietary shifts. However, trophodynamics can be influenced by physiological factors such as growth and sexual maturity. M flavolineatus shift from a pelagic to a macrobenthic diet, which is equilibrated at the adult stage. Results from combined stomach contents (prey volume) and stable isotope analyses suggested a dominant contribution of polychaetes (macrofauna), possibly through selective feeding. Conversely, on the basis of prey volume and stable isotope data, meiofauna did not feature significantly in the diet despite their high abundance in stomachs. Two adult groups were distinguished based on their delta N-15 values (11.9 +/- 0.8 and 7.8 +/- 0.6 parts per thousand), indicating possible stage-specific partitioning in habitat use inside the reef.
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ISSN 0171-8630 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 17
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