THE STEINHART AQUARIUM - Gulf of Guinea Science ...

crown. Non-crowded (solitary) individuals to
25 cm tentacular crown width. Column colored
white to light green. Tentacles are tipped
pink, blue or purple. The wartlike tubercules
are branched.
Diet: Copepods, isopods, amphipods and other
very small animals. Zooplankton captured with
tentacles. Zooxanthellae (dinoflagellates) and
zoochlorellae (unicellular green algae) endosymbionts
supplement their host’s nutrition.
Reproduction and Development: Sexes are
separate; reproduce sexually. Sperm released
throughout summer. Also reproduce asexually
by longitudinal fission. The latter process results
in clones of same-sexed individuals in concentrations
of several hundred individuals per m 2 .
Mortality/Longevity: Like other anemones
may decrease in size if starving.
Preyed upon by nudibranchs such as the shag
rug, Aeolidia papillosa , snails, and sea stars such
as the leather sea star, Dermasterias imbricata.
Conservation status: Tide poolers often march
over and crush colonies.
Remarks: In laboratory conditions, aggregating
anemones with endosymbionts move toward
or away from light, apparently to maximize
optimum light intensity. Anemones kept in
darkness for long periods lose all endosymbionts
and don’t move toward light when light is
reintroduced to their environment.
Anemones with endosymbionts expand in
moderate light and contract in strong light;
anemones lacking endosymbionts do not expand
and contract.
Pebbles, shell fragments and bits of sea algae
readily adhere to this anemone’s flesh when it
is above the tideline. This adaptation results in
reduced desiccation (sunlight is reflected, not
unlike an aluminum roof).
Abutting colonies have “clone wars” with their
neighbors. Stinging cells (nematocysts) are
used to destroy their enemy’s flesh.
Giant Green Anemone
Anthopleura xanthogrammica (Actiniidae)
Distribution: Alaska to Panama.
Habitat: Rocky intertidal, tide pools and wharf
pilings; attach firmly to substrate. Usually
solitary; in favorable locations can occur in
numbers to 14 per m 2 .
Appearance: Column to 30 cm tall and 17 cm
California Academy of Sciences
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in diameter; tentacular crown to 25 cm diameter.
Contracted animals form a hemispherical
mound. Colored green to dark greenish-brown,
occasionally white.
Diet: Detached mussels and sea urchins, also
take crabs and small fishes. Zoochlorellae
endosymbionts supplement host’s diet with
organic materials produced by photosynthesis.
Also have symbiotic zooxanthellae.
Reproduction: Sexual; release sperm and
brownish eggs from late spring through summer.
Hatched larvae float freely and become
widely dispersed before settling.
Mortality/Longevity: Tentacles are chomped
by the shag rug nudibranch Aeolidia papillosa
and the gastropod Tinted Wentletrap Epitonium
tinctum. The column is consumed by the wentletrap
snails Opalia chacei and O. funiculata, as well
as the seaspider Pycnogonum stearnsi. Some sea
stars also include this giant green species on their
menu, especially smaller anemones.
Conservation status: Tide poolers often march
over and crush colonies.
Remarks: Green color is due to presence of a
fluorescent green pigment in the epidermis,
as well as zoochlorellae (symbiotic unicellular
green algae.) Anemones in caves and shaded
areas may lack endosymbionts and are thus
colored very light green or white.
The hermit crab Pagurus samuelis often
scampers around on the giant green anemone;
perhaps the crab becomes so covered with
the host’s mucus that the anemone can’t
distinguish itself from the crab. Since hermit
crabs ingested into the gastrovascular cavity
are released, perhaps there is an as yet to be
described symbiosis.
Condylactis Sea Anemone
Condylactis sp. (Actiniidae)
Distribution: Found throughout the Caribbean
and Western Atlantic; also Indo-Pacific.
Habitat: Found in lagoons or on inner reefs.
Appearance: Disc size: 10–40 cm.
Diet: Like many other cnidarians, these
anemones host zooxanthellae. Also collect
small invertebrates and fishes with their
tentacles.. The amount of food they eat
determines how fast they grow.
Reproduction and Development: Male and
female release eggs and sperm into the water.