Distribution and retention of Sabellaria alveolata larvae (Polychaeta: Sabellariidae) in the Bay of Mont-Saint-Michel, France
Dubois, S.F.; Comtet, T.; Retière, Ch.; Thiebaut, E. (2007). Distribution and retention of Sabellaria alveolata larvae (Polychaeta: Sabellariidae) in the Bay of Mont-Saint-Michel, France. Mar. Ecol. Prog. Ser. 346: 243-254. https://dx.doi.org/10.3354/meps07011 In: Marine Ecology Progress Series. Inter-Research: Oldendorf/Luhe. ISSN 0171-8630; e-ISSN 1616-1599, more |  |
| Keywords | Behaviour > Migrations > Vertical migrations
English Channel
Sabellaria alveolata (Linnaeus, 1767) [WoRMS]
Marine/Coastal |
| Authors | | Top | - Dubois, S.F.
- Comtet, T.
- Retière, Ch.
- Thiebaut, E., more
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| Abstract | ABSTRACT: The gregarious polychaete Sabellaria alveolata is an important foundation species whose reef structures add topographic complexity and high levels of biodiversity in sandflats. In the Bay of Mont-Saint-Michel, France, S. alveolata reefs are considered the largest reef formations in Europe and are increasingly endangered by anthropogenic pressure. In order to understand the role of larval transport on the resilience capacity of these biogenic reefs, multiple complementary approaches were carried out within the bay in 2002 to study horizontal and vertical distribution of S. alveolata larvae and assess larval dispersal processes. Plankton samples collected twice a month from March to October showed an extended period of larval occurrence, from the end of April to October, with 2 peaks of high abundance. The main spawning period occurred early in May, and asmaller peak occurred in September. Mean planktonic lifetime has been calculated to be between 4 and 10 wk. At large scale, larval distribution was patchy and the maximal abundance could reachabout 28 000 larvae m–2. Larval densities were strongly correlated with physico-chemical parameters so that larvae were more abundant in a warmer and less saline coastal water mass characterised by a higher concentration in chlorophyll a. The presence of a large anticyclonic gyre in the bay seemed to play a significant role in controlling larval dispersal by concentrating larvae within the bay. At 1 station in the bay, short-term variations of larval abundances in the water column appeared to be regulated by the tidal cycle, as larvae were more abundant at the end of ebb tide, confirming the very coastal distribution of larvae. Furthermore, S. alveolata larvae tended to migrate closer to the surface during flood and near the bottom during ebb, promoting a net landward transport of larvae. Despitea long larval lifespan, our results indicate that tidal residual currents, especially a coastal gyre, and tidal vertical migration may favour larval retention within the bay. |
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