A predatory gastropod as the potential biological control agent of the Korean invasive mussel, Mytilus galloprovincialis (Lamarck, 1819)

The classical biological control, which is the intentional introduction of exotic species to manage the biological invasion, is the standard measure if the human-mediated management is no longer effective. This method, however, involves a latent risk that the introduced exotic species brings about the nontarget effect on indigenous native species. Applying the native natural predator is the best alternative to control the invasive alien species without the substantial change into the ecosystem of the area invaded. Here, we introduced an indigenous Korean muricid gastropod Reishia bronni (Dunker, 1860), a potential natural predator of the Mediterranean mussel Mytilus galloprovincialis (Lamarck, 1819), a well-known invasive alien species successfully settled down in Korea. In the biomonitoring survey on the Korean ports of the east coast between 2007 and 2011, we have observed the spread of R. bronni within the Mytilus galloprovincialis community. The observed decrease of the mussel density around the gastropod assemblage led us to the idea that R. bronni is the natural predator of M. galloprovincialis. In order to clarify such a predator-prey interaction between both species, we performed a field observation from two Korean ports in August 2012, keeping R. bronni and M. galloprovincialis individuals together into the cages for 18 days. Then, we counted the number of latter ones consumed and estimated the average time spent feeding per individual of R. bronni. We observed the positions of the drill holes made on the consumed shells by it. Our results showed that R. bronni is the active natural predator of M. galloprovincialis with the high feeding intensity and the unique foraging behavior targeting the lateral margin of the shell, so-called “Marginal drilling”. Therefore, we could suggest the possibility that R. bronni can be applied to control the mass spread of M. galloprovincialis.