NAS - Nonindigenous Aquatic Species
Bryozoans
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Bryozoans (Phylum Bryozoa) are
colonial, sessile animals that are usually encased in a protective covering with
an opening for the animal's protruding tentacles. Each individual is very small
and measures only several millimeters in length. They are usually found in marine
environments, although some species are found in fresh water. Standard methods
of introduction include ship fouling or transportation in ballast water of ocean-going
vessels. Potential impacts include competition with native species for suitable
substrate and effects on organisms to which they attach. An example of a nonindigenous
bryozoan is the lacy-crust bryozoan, Membranipora membranacea (pic
139k), which has been introduced to the coast of New England. Within three
years of its introduction it had become the dominant kelp epiphyte off the coasts
of New Hampshire and Maine. Kelp encrusted with this introduced bryozoan are more
susceptible to breakage during storms. As a result the lacy-crust bryozoan has
apparently contributed to the defoliation of the kelp beds in this region. The
reduction in the kelp beds resulted in a dramatic decline of the sea urchin. The
lacy-crust bryozoan has also been found to competitively exclude the native encrusting
animals in New England for suitable substrate.
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Data Queries and Species Lists
Links to News and Other Information
The
Bryozoa Home Page (many links)
Families
of bryozoans, genera, pictures
Bryozoans
- general information
Introduction
to the Bryozoa
Bryozoan
Colour Illustrations
Exotics
in Monterey Bay National Marine Sanctuary