Biofouling
Guides
Amphibalanus
acorn barnacle
Amphibalanus is a genus of acorn barnacles in the family Balanidae, established by Pitombo in 2004 to accommodate species formerly assigned to Balanus. The genus contains multiple species including the widespread and economically significant Amphibalanus amphitrite and A. improvisus. These barnacles are characterized by their conical calcareous shells, cemented base, and planktonic larval stages culminating in a settlement-competent cyprid stage. Several species have become established outside their native ranges as invasive biofouling organisms in ports and harbors worldwide.
Amphibalanus amphitrite
striped barnacle, purple acorn barnacle, Amphitrite's rock barnacle
Amphibalanus amphitrite is a medium-sized acorn barnacle with distinctive purple or brown vertical stripes. It is a globally distributed marine species native to warm and temperate waters, now recognized as a significant biofouling organism. The species has become a model organism for larval settlement research due to its invasive potential, worldwide distribution, and ease of laboratory culture. Its genome has been sequenced, and extensive neurobiological studies have examined the settlement behavior of its cyprid larvae.
Caprella mutica
Japanese Skeleton Shrimp
Caprella mutica is a highly invasive caprellid amphipod native to the Sea of Japan. It has spread to temperate coastlines worldwide through maritime shipping and aquaculture, becoming established in the North Atlantic, North Pacific, New Zealand, and most recently South America. The species exhibits pronounced sexual dimorphism, with males reaching 50 mm and females averaging 15–20 mm. It is characterized by densely setose first and second pereonites in males and remarkable ecological plasticity, enabling dense populations on artificial structures.
Caprellidae
Skeleton Shrimp, Ghost Shrimp
Caprellidae is a family of marine amphipods known as skeleton shrimps, characterized by their slender, threadlike bodies that provide camouflage among seaweed, hydroids, and bryozoans. They exhibit extreme sexual dimorphism, with males typically much larger than females. The family contains 88 genera across three subfamilies and is distributed worldwide in marine environments from intertidal zones to deep sea depths. Some species have been documented as invasive, spreading through biofouling on aquaculture equipment.
Chthamalidae
Chthamalid Barnacles
Chthamalidae is a family of small, intertidal barnacles in the superfamily Chthamaloidea. The family includes at least 56 recognized species across 14 genera. Members are distinguished by a primary shell wall of eight, six, or four plates without imbricating whorls, and a membranous or rarely calcareous basis. They occupy the highest intertidal zones, often in wave-washed habitats where other barnacle families cannot survive. Molecular studies have revealed extensive cryptic diversity, with many species separable only by DNA analysis.
Jassa marmorata
Marbled Scud
A tube-building amphipod native to the northeast Atlantic Ocean, now introduced to northeast Asia. Distinguished by greyish coloration with reddish-brown markings and a maximum length of 10 mm. Notable for exhibiting two distinct male morphs with alternative mating strategies: larger 'major' males that fight for access to females, and smaller 'minor' males that sneak copulations. Constructs protective tubes from detritus and algae fragments bound with mucus secretions.
Lepas
Goose Barnacles
Lepas is a genus of goose barnacles in the family Lepadidae, comprising pelagic crustaceans that attach to floating substrates using a flexible stalk. The genus includes at least eight described species, with Lepas anatifera being among the most widely distributed and studied. Members of this genus are characterized by their stalked morphology and calcareous shell plates, representing a distinctive lineage within the barnacle group.
Thecostraca
Barnacles and Allies
Thecostraca is a class of marine crustaceans encompassing over 2,200 described species, with barnacles (subclass Cirripedia) comprising the vast majority. The group includes three major lineages: sessile suspension-feeding barnacles, parasitic ascothoracidans that infect cnidarians and echinoderms, and the enigmatic Facetotecta, known only from planktonic larvae. Members undergo distinctive larval development, typically featuring a nauplius stage followed by a cypris stage that facilitates settlement. Thecostraca exhibits remarkable life history diversity, ranging from free-living suspension feeders to endoparasites with highly derived morphologies.