Hydroides

Hydroides is a genus of sessile marine worms in the family Serpulidae. Members construct hard calcareous tubes that are cemented to solid substrates, including rocks, pilings, docks, ships, and other artificial surfaces. The tubes are typically white or pale and can form dense colonies. The worm lives inside the tube and, when feeding, extends a crown of feathery, ciliated tentacles to capture suspended particles from the water.

Species of Hydroides occur worldwide in shallow coastal environments, especially in bays, harbors, and estuaries. They are particularly common on man-made substrates, making them a well-known group in marine biofouling. Their presence on ships, underwater pipelines, aquaculture equipment, and other submerged structures can be economically significant due to increased drag, maintenance costs, and potential corrosion of infrastructure.

Ecology and reproduction: Hydroides species are filter feeders and reproduce sexually as broadcast spawners. They release eggs and sperm into the water column, producing free-swimming larvae that eventually settle on suitable surfaces and secrete a tube. Settlement is influenced by surface characteristics, biofilms, and microbial cues that help larvae recognize appropriate substrates.

Taxonomy and diversity: The genus Hydroides comprises multiple species within the Serpulidae family. They are distinguished by variations in tube morphology, coloration, and ecological preferences, contributing to their widespread distribution in marine environments. Hydroides elegans, in particular, is notable for its role as a model fouling organism and for its status as an invasive species in some regions.