Potentially Misidentified Species:
B. maxima could be confused with B.
gracilis due to overall morphological similarity. However, zooids of B.
maxima are significantly larger than those of B. gracilis. In
addition, living specimens of B. maxima have star-shaped, brilliantly
pigmented white cells in the stolon and zooids, with white pigmentation
extending into the lophophore and tentacles (Winston 1982).
II. HABITAT AND
Winston first described B. maxima from
the Indian River Lagoon, Florida in 1982. It has since been documented in
Jamaica at both Discovery Bay and Port Royal. The distribution of this
species is likely to be significantly more widespread. Winston (1982)
suggested some of the variability in species descriptions for B. gracilis
in other areas was perhaps due to the occurrence of both B. gracilis
and B. maxima in samples.
Specimens of this new species were collected in
abundance from the IRL in the Sebastian Inlet grass flats area, and
coastally at Walton Rocks and Sebastian (Winston 1982, 1995).
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
In living specimens of this species, functional
zooids ranged in length from 0.91 - 1.46 mm (average: 1.14 mm), and from
0.200 - 0.273 mm (average: 0.230 mm) in length. Degenerated zooids ranged in
length from 0.419 - 0.737 mm (average: 0.575 mm), and from 0.20 - 0.30 mm in
width. Stolons ranged from 0.091 - 0.182 mm in width, averaging
approximately 0.134 mm. The gizzard within the polypide averages
approximately 0.119 X 0.139 mm in size, and the lophophore measured
approximately 0.751 mm in diameter.
Winston (1995) lists B. maxima as one of
the most abundant bryozoan species in the Indian River Lagoon.
Bowerbankia species brood embryos in
zooids until they develop into ovoid, ciliated, non-feeding larvae with a
short planktonic life. The reproductive season of B. maxima is
IV. PHYSICAL TOLERANCES
B. maxima is collected in March through
September in the Indian River Lagoon. It has not been observed in the
B. maxima was typically collected from
areas in the IRL where salinity was below 30‰, and is thus considered to
be euryhaline (Winston 1995).
V. COMMUNITY ECOLOGY
B. maxima, like all bryozoans, is a
suspension feeder. Each individual zooid in a colony has 8 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.
Typical habitat for ectoprocts in the Indian
River Lagoon include seagrasses, drift algae, oyster reef, dock, pilings,
breakwaters, and man-made debris (Winston 1995). In the Indian River Lagoon,
B. maxima was collected in association with seagrasses and algae,
specifically the Rhodophyte Solieira spp., from March through
November. Coastally, this species is found on shells, rocks, algae,
hydroids, and other bryozoans. Colonies of this species form large masses
that overgrow other organisms on beach rock ledges, or on breakwaters
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,
VI. SPECIAL STATUS
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
Report by: K. Hill,
Smithsonian Marine Station
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Page last updated: July 25, 2001