Sessile Organisms

Image Common Name Scientific Name Category Species Origin Description Habitat Diet
Slipper snails image Slipper snails Crepidula spp. (Eastern slipper snail C. plana and Atlantic slipper snail C. fornicata) Molluscs Native - non-endemic Whitish single-shelled molluscs found in shallow nearshore habitats, with smooth, curved upper shells Two species of small gastropod mollusk found in the low intertidal to subtidal associated with rocks, pier pilings and oyster beds Graze on algae and detritus found on hard substrates
Eastern mudsnail image Eastern mudsnail Ilyanassa obsoleta Molluscs Native - non-endemic Brown to black cone-shaped spiraled shell found in large numbers in muddy habitats Abundant in intertidal estuarine areas with muddy substrates Feeds on algae, worms and detritus within the muddy sediment
Boring sponges image Boring sponges Cliona spp. Sponges Native - non-endemic A very small yellow sponge that bores into oyster and mussel shells Sponges are found on hard substrates such as rocks, pier pilings and algae, with their boring habit meaning that their tissues become intertwined with the substrate Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
None/Sediment image None/Sediment N/A N/A N/A N/A N/A N/A
Northern rock barnacle image Northern rock barnacle Semibalanus balanoides Crustaceans Native - non-endemic Barnacles with six broad and low whitish plates arranged in a ring around a central diamond-shaped plate. Cemented to hard substrata, usually found in clumps Inhabits shallow intertidal and subtidal marine areas, cemented to hard substrata such as rocks and pier pilings Barnacles are filter feeders, feeding on algae, zooplankton and detritus particles in the water column
Ivory barnacle image Ivory barnacle Amphibalanus eburneus Crustaceans Native - non-endemic Barnacle with whitish plates forming a steep cone, with soft parts often colored or striped. Found in clumps on hard substrata Found cemented to hard substrata such as rocks and pier pilings in the intertidal and shallow subtidal, preferring brackish waters Barnacles are filter feeders, feeding on algae, zooplankton and detritus particles in the water column
Mud tube worm image Mud tube worm Streblospio benedicti Worms Native - non-endemic Tube-dwelling reddish colored segmented worm up to 6 mm in length In the Order Polychaeta (marine segmented worms). Lives in fine sandy and silty sediments, building tubes of sediment and mucus Feeds on detritus on the sediment surface
Hard tube worms image Hard tube worms Family Serpulidae - serpulid worms, Subfamily Spirorbinae - spirorbid worms Worms Native - non-endemic Worms living inside small whitish hard tubes that are either coiled (spirorbid worms) or straight (serpulid worms) Found attached to hard substrata such as rocks, pier pilings and oyster shells. Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Tube-building polychaete image Tube-building polychaete Polydora cornuta (formerly Polydora ligni) Worms Native - origin uncertain Bristled worm with two long frontal appendages living inside muddy tubes on sediment-covered surfaces Builds mud-covered detrital tubes in the intertidal and shallow subtidal waters of estuaries. Naturally prefers muddy clay substrates and can be found on settlement tiles where sediment has accumulated Feeds on small food particles on the sediment surface using their pair of long frontal palps.
Golden star tunicate, star ascidian image Golden star tunicate, star ascidian Botryllus schlosseri Tunicates Introduced - Mediterranean A colonial tunicate that grows in a gelatinous sheet, rubbery to the touch, on hard surfaces. Zooids form a star-like patterns across the surface A colonial ascidian that grows as a gelatinous sheet with tiny individual modules, called zooids, embedded in a common tissue matrix. Found on hard substrata such as pier pilings, oyster cages, macroalgae and settlement tiles Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Chain tunicate image Chain tunicate Botrylloides violaceus Tunicates Introduced - Asian Pacific coast A colonial animal that grows in a gelatinous sheet on hard surfaces, with zooids resembling meandering chains of tiny circles across the surface. Orange to brown in color, with zooids a single color. A colonial ascidian that grows as a gelatinous sheet with tiny individual modules, called zooids, embedded in a common tissue matrix. Found on hard substrata such as pier pilings, oyster cages, macroalgae and settlement tiles Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Orange sheath tunicate image Orange sheath tunicate Botrylloides diegensis Tunicates Introduced - Asian Pacific coast A colonial animal that grows in a gelatinous sheet on hard surfaces, with oval-shaped zooids arranged in rows or dense clusters. Orange in color, with zooids two colors. A colonial ascidian that grows as a gelatinous sheet with tiny individual modules, called zooids, embedded in a common tissue matrix. Found on hard substrata such as pier pilings, oyster cages, macroalgae and settlement tiles Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Sea grapes image Sea grapes Molgula manhattensis Tunicates Native - non-endemic Globular grey animals with two protruding siphons, commonly heavy foulers of oyster cages Found attached to hard substrata such as rocky reefs, pier pilings, ropes and other artificial structures in shallow subtidal marine and brackish waters. Often found heavily encrusting oyster cages M. manhattensis is a filter feeder on plankton and detritus
Sea vase image Sea vase Ciona intestinalis Tunicates Introduced - origin uncertain Translucent slender banana-shaped ascidian with small siphons at the end, occur in clumps Found in shallow waters attached primarily to artificial hard surfaces. Can occur in large numbers Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Sea squirt image Sea squirt Ascidiella aspersa Tunicates Introduced - origin uncertain Solitary ascidian similar to Molgula manhattensis but more oval in shape with conical siphons with colored edges. Body pale in color with a lumpy outer surface. Found attached to hard substrata such as rocky reefs, pier pilings, ropes and other artificial structures in shallow subtidal marine and brackish waters. Often found heavily encrusting oyster cages Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Red beard sponge image Red beard sponge Clathria prolifera (formerly Microciona prolifera) Sponges Native - non-endemic Reddish sponge that encrusts hard substrates in shallow waters. Irritating to skin ��� do not handle directly! Found in low intertidal to shallow subtidal waters in estuaries. Encrusts on hard substrates such as reefs and pier pilings, forming raised lobes or cups up to 200 mm tall in larger specimens and in deeper water Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Lacy bryozoan image Lacy bryozoan Membranipora membranacea Bryozoans Introduced - US west coast, Europe Colonies form thin whitish sheets with tiny box-like zooids in a lacy pattern Found encrusting a variety of subtidal surfaces, including rocks, pier pilings, shells and algae Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Conopeum bryozoans image Conopeum bryozoans Conopeum spp. (C. tenuissium and C. seurati are very similar) Bryozoans Introduced - US Gulf Coast Encrusting colonies form whitish sheets, with oval-shaped zooids Found encrusting hard surfaces such as rocks and mollusc shells Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Orange bryozoan image Orange bryozoan Watersipora subtorquata Bryozoans Introduced - origin uncertain Colonies may be encrusting or lobed with red-orange zooids Found encrusting hard surfaces such as rocks, pier pilings and shells as unilaminar sheets. More upright, lobed forms may be found in calm waters. Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Bushy brown bryozoan image Bushy brown bryozoan Bugula neritina Bryozoans Introduced - origin uncertain Upright, tree-like bushy colonies, purple to brown Found attached to hard substrates such as pier pilings and rocks as well as algae and shells Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Hydroids image Hydroids Subclass Hydroidolina Cnidarians Native - non-endemic Tiny translucent colonies that may be feather-like, tree-like or form runners over the surface A very large and complex group of cnidarian species that have a colonial life stage attached to substrata such as rocks, pier pilings, shells, algae, seagrass and other structures Capture microscopic algae, zooplankton and detritus in the water
Frilled anemone image Frilled anemone Metridium dianthum (formerly M. senile) Cnidarians Native - non-endemic Solitary polyp attached to substrate with creamy yellow to brown coloration and many tentacles Found on hard substrata such as rocks and pier pilings in the intertidal and shallow subtidal. The most common anemone on the northeast coast. Feed on live and dead animals from zooplankton through to fish.
Northern red anemone image Northern red anemone Urticina felina Cnidarians Native - non-endemic Solitary polyp attached to substrate with reddish coloration and short, banded tentacles Found on lower intertidal shores on hard substrata such as rocks and pier pilings, as well as in gravel or shell debris. Feed on live and dead animals from zooplankton through to fish.
Oyster drill image Oyster drill Urosalpinx cinerea Molluscs Native - non-endemic A small pale-colored shell with sharply pointed cone and parallel ridges around shell. Predator of oysters and mussels Found in shallow subtidal marine and estuarine regions in association with bivalve and barnacle beds Filter feeders, ingesting microscopic algae, zooplankton and detritus particles from the water
Blue mussel image Blue mussel Mytilus edulis Molluscs Native - non-endemic Blue-black with two hinged shells that open to feed, found in clumps attached to hard intertidal and shallow substrata Found in the intertidal and shallow subtidal in clusters to rocky substrates or pier pilings. Individuals attach to the substrate using sticky byssal threads Mussels are filter feeders, ingesting bacteria, plankton and small detritus particles suspended in the water
Ribbed mussel image Ribbed mussel Geukensia demissa Molluscs Native - non-endemic Green-brown bivalves found in muddy intertidal areas with ribs running the length of each shell Found in the intertidal zone of marine and brackish waters attached to marsh plants or rocky substrates or embedded in sediment A filter feeder that ingests plankton and detritus from the water column