How to Distinguish from Similar Species: The only other sponge regularly found growing on scallops in this region is Myxilla incrustans, which is bright yellow to brown. M. W. de Laubenfels (quoted in Ricketts et al.) says that Mycale adhaerens may also be distinguished by comparatively coarser structure and by the fact that, when torn, it reveals prominent fibers thicker than thread, absent in Myxilla. (see photo). Lambe also said that the oscula in Mycale adhaerens were much smaller than those in Myxilla encrustans.
Habitat: Live symbiotically on scallop shells.
Biology/Natural History: Nudibranches which graze on this sponge include Archidoris odhneri and Anisodoris nobilis. The symbiosis is likely mutualistic. If one of the major predators of the scallop, the seastar Evasterias troschelii, encounters the scallop (and the scallop does not swim away) the seastar often turns away if it touches the sponge; likely in response to some secretion or to the spicules from the sponge. The sponge also appears to make it more difficult for the seastar's tube feet to adhere to the scallop. If the sponge is removed from the scallop and the scallop is prevented from swimming, it is readily captured by the seastar. The scallop will also swim from predators of the sponge, such as Archidoris spp, so the sponge is benefited as well. The swimming scallop may also help carry the sponge into areas with clean water and good currents, and help prevent fouling of the sponge.
Research by Kirt Onthank and Thomas Ewing at the Walla Walla
Rosario Marine Laboratory indicates that sponge encrustation deters
predation by octopus Enteroctopus
dofleini and Octopus
rubescens, both of which may be important scallop
Kozloff 1987, 1996
General Notes and Observations: Locations, abundances, unusual behaviors:
Neither Myxilla incrustans nor Mycale adhaerens last long in running seawater tanks. Within a few days they begin to slough off the scallops. Perhaps they need strong and nearly constant water flow. We find scallops with sponges primarily in areas subject to strong currents.
Mycale adhaerens is less common on scallops in the Rosario area than is Myxilla incrustans. Some areas seem to have only Myxilla encrustans, while others have mostly Myxilla encrustans and some Mycale adhaerens. This identification is made just by sight--the yellow symbiotic ones are assumed to by Myxilla incrustans.
In 2006 we sampled a number of freeliving sponges and found Mycale adhaerens in a number of different places, including yellow branching specimens from the mud of Padilla Bay and yellow encrusting specimens from Northwest Island.
Mycale adhaerens is not limited to growing
The sponge shown below is often found growing in Padilla Bay near March
Point June 2006. It is tan with yellowish parts when fresh
fades to all tan after being collected. According to the
and growth form this is also Mycale adhaerens.
Authors and Editors of Page:
Dave Cowles (2005): Created original page