Wood-boring bivalves, opportunistic species in the deep sea.

Wood exposed for 104 days at a depth of 1830 meters at the permanent station of the research submersible D.S.R.V. Alvin was completely riddled by two species of bivalve wood borers (subfamily Xylophagainae, family Pholadidae). Their high reproductive rate, high population density, rapid growth, early maturity, and utilization of a transient habitat classify them as opportunistic species, the first recorded from the deep sea. Xylophaga is shown to be the most important species involved in decomposing woody plant material in the deep sea.