Practical implementation of in vitro culture of Lanice conchilega (Polychaeta) in a coastal defence context

ABSTRACT Current coastal protection measures become increasingly insufficient under circumstances of climate change and increasing anthropogenic pressures. Aggregations of the ecosystem engineer Lanice conchilega (Pallas, 1766) stabilize the sediment bed of sandy shorelines. Therefore, this polychaete is considered an interesting target species in the search for nature-inspired designs in coastal zone management. This study investigated the potential of L. conchilega as a resilient coastal builder by trying to cultivate them and enhancing the larval settling process by using artificial substrata. A closed Recirculating aquaculture system (RAS) combining spawning induction and larval rearing was designed and tested. The tanks with adults were exposed to different photoperiods prior to water temperature rise. A spawning and fertilisation event was recorded in the 0:24 Light:Dark (LD) tank up to the trochophore stage. Additionally, the temperature-shock spawning induction method was experimentally proved effective. All practical experience on the in vitro spawning induction and larval rearing of L. conchilega is discussed and summarized as a guideline for future culturing trials. In vitro substratum settlement experiments with aulophore larvae sampled with plankton hauling revealed the potential of artificial substrata to trap larvae. Nonetheless, a preference in substratum type is not to be excluded yet.