EFFECTS OF INDIVIDUAL BEHAVIORS, INTER-INDIVIDUAL INTERACTIONS WITH ADULT PECTINARIA KORENI AND OWENIA FUSIFORMIS (ANNELIDA, POLYCHAETA), AND HYDRODYNAMISM ON PECTINARIA KORENI RECRUITMENT
Résumé
The English Channel is a megatida\ sea characterized by large tidal currents in which the
larvae of are dispersed on a large spatial scale by tidal currents. They settle
abundantly on a wide edaphic spectrum, but the populations of adults are confined to bays
and estuaries. Laboratory experiments under still water and flume flows showed that postlarvae
of were able to actively select a suitable substrate i) on a macrospatial scale
by resuspending themselves in the water column; ii) on a microspatial scale by crawling at
the sediment surface. Adults also intluenced the post-larvae habitat selection. When postlarvae
settle on a suitable sediment in presence of adults, they resuspend themselves immediately.
This resuspension phenomenon is a consequence of bioturbation by the adults (subsurface
deposit feeders) whose vertical movement and fecding activity are mainly dependent
on hydrodynamic conditions. However, in the presence of adults (deposit/
filter feeders), resuspension rates were weak. This recruitment facilitation might be interpreted
as a limitation of post-larval resuspension abilities, tubes in a gregarious distribution
stabilizing the sediment and resembling particle traps. The feeding behavior of fusiformis,
which exhibited high plasticity in relation to hydrodynamism, also influenced the post-larvae
response.
Domaines
Biodiversité et Ecologie
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Licence : CC BY NC ND - Paternité - Pas d'utilisation commerciale - Pas de modification