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Species Name:    Bugula neritina
Common Name:                 (None)

 

I.  TAXONOMY

Kingdom Phylum/Division: Class: Order: Family: Genus:
Animalia Ectoprocta Gymnolaemata Cheilostomata Bugulidae Bugula
 
        
Detail of Bugula neritina showing large ovicells attached at the distal corners of individual zooids.  Note the lack of spines and avicularia.  Drawing by J. Winston, courtesy of the American museum of 
Natural History.  Used with permission.  

 

 

 

 

Species Name:
Bugula neritina (Linnaeus), 1758

Common Name:
None

Species Description:
B. neritina is an erect, arborescent bryozoan whose colonies form brown or reddish tufts on whatever substratum they encounter. It is a common and abundant member of the fouling community (Winston 1995). Zooids are large and measure an average of 0.97 X 0.28 mm. Zooids alternate biserially on branches, with individual zooids tapering proximally. A membrane covers the frontal surface. B. neritina differs from other species in this genus in that it possesses no avicularia and no spines. Rather, its zooids have sharp points in the distal corners. The lophophore measures an average of 0.764 mm in diameter and bears 23 tentacles.

Synonymy:
Sertularia neritina Linnaeus, 1758

Other Taxonomic Groupings:
Suborder: Anasca


II.  HABITAT AND DISTRIBUTION 
Regional Occurrence:
B. neritina is a highly cosmopolitan and abundant species throughout warm water areas of the world and is considered a troubling fouling organism.

IRL Distribution:
B. neritina occurs throughout the Indian River Lagoon and along the Florida coast.


III.  LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Zooids are large and measure an average of 0.97 X 0.28 mm. The lophophore measures an average of 0.764 mm in diameter and bears 23 tentacles.

Abundance:
B. neritina is one of the most abundant bryozoans in the IRL and an important member of the fouling community. It is most common in the winter months where it and B. stolonifera dominate bryozoan populations on hard substrata such as seawalls and docks (Winston 1995). It does however, show a fluctuating pattern of abundance. In some years it is a dominant species from late fall through late spring. In other years, it is sparsely distributed.

Locomotion:
Sessile

Reproduction:
B. neritina has large ovicells that are attached to the distal corners of zooids and oriented at angles to the axis of the branch. In temperate waters, B. neritina reproduces in summer and fall. In the IRL, reproduction occurs in the cooler months. Older colonies appear to "over-summer." Winston (1982) reported that colonies collected coastally in June and July were brown in color and appeared to be nearly completely degenerated, with many zooids dead or filled with ciliates. However, closer examination revealed functional zooids present in the distal ends of the colony.

Embryology:
Embryos brooded in ovicells are dark brown in color and measure approximately 0.25 mm in diameter (Winston 1982).


IV.  PHYSICAL TOLERANCES
Temperature:
Though B. neritina is eurythermal, it can be sensitive to cold. Winston (1982) reported that Bugula neritina colonies collected from intertidal areas of Sebastian Inlet after a cold event were all dead. This sensitivity to cold water temperatures may help to explain the fluctuating abundance pattern in this species.

Winston (1978) reported that B. neritina has apparently developed an adaptation for feeding on zooplankton. By twisting the ends of its tentacles together to form a cage of sorts, B. neritina is able to filter out active ciliates and other protists.


V.  COMMUNITY ECOLOGY
Trophic Mode:
B. neritina, like all bryozoans, is a suspension feeder. Each individual zooid in a colony has 23 ciliated tentacles that are extended to filter phytoplankton less than 0.045 mm in size (about 1/1800 of an inch) from the water column. Bullivant (1967; 1968) showed that the average individual zooid in a colony can clear 8.8 ml of water per day.

Habitats:
Typical habitat for ectoprocts in the Indian River Lagoon include seagrasses, drift algae, oyster reef, dock, pilings, breakwaters, and man-made debris (Winston 1995).

Associated Species:
Seagrasses as well as floating macroalgae, provide support for bryozoan colonies. In turn, bryozoans provide habitat for many species of juvenile fishes and their invertebrate prey such as polychaete worms, amphipods and copepods. (Winston 1995). Bryozoans are also found in association with other species that act as support structures: mangrove roots, oyster beds, mussels, etc.


VI.  SPECIAL STATUS
Special Status:
None.

Benefit in IRL:
Bryozoans are ecologically important in the Indian River Lagoon due to their feeding method. As suspension feeders, they act as living filters in the marine environment. For example, Winston (1995) reported that bryozoan colonies located in 1 square meter of seagrass bed could potentially filter and recirculate
an average of 48,000 gallons of seawater per day.

Economic Importance:
None.

 

Report by:  K. Hill, Smithsonian Marine Station
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Page last updated: July 25,  2001