Boring Sponge

Cliona spp.

The boring sponge, a major pest to Bay oysters, is a thick, bright yellow sponge.

Where does the boring sponge live?

Boring sponges grow on oyster beds and other mollusk colonies throughout the Bay. The sponge may overwhelm beds in some areas, but may not be present in others.

What does the boring sponge eat?

Boring sponges are suspension feeders. They draw water in through tiny pores and filter out plankton, organic material and other microscopic particles.

How does the boring sponge reproduce?

Boring sponges can reproduce both sexually and asexually. Asexual reproduction takes place in three different ways:

• An adult sponge breaks apart due to waves, currents or damage from a predator.
• Part of a sponge buds and breaks off.
• A sponge produces clusters of cells in autumn that overwinter and develop into new sponges in spring.

Sexual reproduction occurs when:

• One sponge releases sperm into the water.
• The sperm is carried to another sponge and fertilizes its eggs internally.
• The fertilized eggs are released into the water, where they develop into larvae.
• After a few hours to a few days, larvae fall to the Bay's bottom and search for a suitable surface to settle on. Once they attach themselves, they metamorphose into juvenile sponges.

Other facts about the boring sponge:

• It is called the "boring sponge" because it bores holes into an oyster's shell. This weakens the shell and can sometimes kill the oyster.
• If you find an empty oyster shell covered with pockmarks, it was once infested by a boring sponge.