Effects of substratum instability on locomotion and pedal laceration in Metridium senile (Anthozoa:Actiniaria)

Abstract

On the west coast of Sweden, populations of the small morph of the sea anemone Metridium senile (L.) are often found associated with beds of the mussel Mytilus edulis (L.). We tested the hypothesis that instability of the secondary substratum provided by mussels affects pedal disc laceration of M. senile by stimulating locomotion. The instability of a subtidal bed of M. edulis was quantified by recording movements of individual mussels. Rates of pedal disc laceration of M. senile were investigated in field and laboratory experiments using live and eviscerated mussels as substrata. Field experiments showed that M. senile produced significantly more lacerates on live mussels than on mimic (eviscerated) mussels. In a laboratory flume experiment, the rate of laceration on mimic mussels increased significantly with the frequency of substratum perturbation (overturning) with maximum laceration rates of groups overturned once every 12 and 48 h. Furthermore, the rate of laceration was found to be a function of anemone body size per se. During periods between overturning of the mimics, anemones showed a significant net migration from the protected lower shell to the exposed upper shell in pace with the frequency of overturning. The presence of a vertical flow velocity gradient between and above the mimics supported the hypothesis that migration was due to a rheotactic response in M. senile. The significance of this behavioral pattern and stimulated clonal growth in structuring populations of M. senlle on unstable substrata is discussed.

Role of the sea anemone Metridium senile in structuring a developing subtidal fouling community

“…Additionally, adult M. senile have shown the ability to detach from the substrate and drift up to several kilometers to recolonize previously depopulated areas (Wahl 1985). Together, clonal growth and locomotion may allow M. senile to be more successful than other sessile invertebrates at colonizing small patches of open space as they arise (Anthony & Svane 1995).…”

The Ecology of Rafting in the Marine Environment. Ii. the Rafting Organisms and Community

“…In this context, Häussermann & Försterra (2001) mentioned the remarkable ability of the sea anemone Anemonia alicemartinae to detach and reattach very rapidly. Many sea anemones have this capacity (e.g., Shick et al 1979, Anthony & Svane 1995, Houtman et al 1997, albeit there apparently exist species-specific differences in motility (see above). Also, byssal-producing mussels can release hold from the original substratum and reattach to new surfaces, as has been discussed by Horvath & Lamberti (1997) for rafted individuals of the zebra-mussel Dreissena polymorpha.…”

Fouling community dominated by <em>Metridium senile</em> (Cnidaria: Anthozoa: Actiniaria) in Bahía San Julián (southern Patagonia, Argentina)

“…However, the mobility of mussel patch aggregates can frequently result in the death of their epibionts, which can be buried or located in unfavourable positions incompatible with life. Thus, the relative instability of the biological substrate, such as mussels, stimulates locomotion of the anemone causing the laceration of the pedal disc and the clonal reproduction of individuals, as observed by Kenneth et al (1995). Moreover, experiments carried out by Nelson and Craig (2011) on artificial substrates show that the movements of M. senile kill new recruits from other fouling organisms by asphyxiation (smothering), possibly due to stress conditions generated by the low concentration of dissolved oxygen below the pedal disc.…”