The Sea Fir (Abietinaria abietina) is a species of colonial hydroid, a type of marine invertebrate that forms branching colonies. Its common name “Sea Fir” alludes to its distinctive tree-like growth habit. Abietinaria abietina is found in diverse marine environments, displaying a wide range of adaptability.
Description & Characteristics
Abietinaria abietina colonies can reach a significant size, growing up to several centimeters in height. Their branches are slender and typically exhibit a reddish-brown coloration. The polyps, the individual feeding units of the colony, are small and located at the tips of the branches. These polyps extend outward to capture food from the surrounding water.
Habitat and Occurrence
Abietinaria abietina is widely distributed in temperate and cold-water marine environments. It is typically found attached to hard substrates like rocks, shells, and seaweeds. This species is particularly prevalent in the intertidal zone, the area between high and low tide marks. Abietinaria abietina is also known to inhabit subtidal zones, extending down to depths of several meters. In terms of marine zones, its presence is prominent in the neritic zone, the coastal region extending from the shoreline to the edge of the continental shelf.
Taxonomy
Abietinaria abietina belongs to the Class: Hydrozoa, a diverse group of marine invertebrates known for their ability to produce colonies. The species further belongs to the Order: Leptothecata, which encompasses hydroids characterized by their slender, branching colonies. Finally, Abietinaria abietina is classified within the Family: Sertulariidae, a family of hydroids known for their distinctive branching patterns and the presence of specialized structures called hydrothecae that house the polyps.
Feeding
Abietinaria abietina is a carnivorous suspension feeder. Its polyps capture food by extending tentacles into the water, trapping small organisms like copepods, plankton, and zooplankton. This feeding strategy allows Abietinaria abietina to thrive in environments with a high concentration of microscopic prey.
Image References