The site of settlement indicates commensalism between bluemussel and its epibiont

Abstract

The site of settlement of barnacles (Balanus improvisus) attached on shells of bluemussels (Mytilus edulis) was mapped from a sample of mussels collected in the Baltic Sea. Most barnacles had settled near the siphonal apertures of the mussel. An experiment was made to measure the disadvantages and advantages that living in close association brings to barnacles and mussels. The barnacles on shells of living mussels were shown to grow significantly faster than those on empty mussel shells. Presence of barnacles had no effects on growth of mussels. The two-species association under study was demonstrated to be a case of commensalism.

Separating the effects of physical and biological aspects of mussel beds on their associated assemblages

“…For example, barnacles attached to living mussels grew faster than those on empty shells, perhaps due to feeding currents created by the mussels (Laihonen & Furman 1986). Fouling assemblages, which include most of the taxa that recruited to these mussel patches, settle readily onto different surfaces, including artificial structures (Sutherland 1980).…”

Short-term study on the early succession stages of fouling communities in the coastal zone of Puck Bay (southern Baltic Sea)

“…Competition for space and food between them is a common occurrence (Dürr, Wahl 2004), usually starting at the beginning of the succession, when the blue mussels form a layer on top of the barnacles. The inverse relation (barnacles on blue mussels) once the macrobenthic succession has become well advanced is indicative rather of commensalisms between the blue mussel and its epibiont (Laihonen, Furman 1986). The most significant changes in the abundance of fouling assemblages at different depths were related to these species.…”

Marine epibiosis. I. Fouling and antifouling: some basic aspects

“…-Filter-feeding epibionts possibly profit from the nutrient currents created by certain hosts (Ryland 1974, Laihonen & Furman 1986). …”