THE STEINHART AQUARIUM - Gulf of Guinea Science ...

anches. Paired branchlets extend from
branches at regular intervals. Coloration is
purple-violet, occasionally whitish to brilliant
yellow. Height to 60 cm.
Diet: Possess zooxanthellae and also filter feed
on plankton.
Mortality/Longevity: Commonly preyed
upon by the flamingo tongue snail (Cyphoma
gibbosum). This snail leaves a dark trail of
exposed gorgonian skeleton where it has
scraped away the soft tissue.
Purple Frilly Sea Plume
Pseudopterogorgia elizabethi (Gorgoniidae)
Distribution: Western Atlantic Ocean; Florida,
Caribbean.
Habitat: Inshore and patch reef flats and
slopes.
Appearance: Usually less than 1 m tall. Side
may be pinnate (paired on opposite sides of the
main branches) but sometimes are not.
Diet: Nutrition from zooxanthellae and
supplemental filter feeding.
Remarks: Compounds that possess nonsteroidal
anti-inflammatory and analgesic
properties have been isolated from this species
and are the subject of active research,
Pacific Gorgonian
Rumphella sp. (Gorgoniidae)
Distribution: Widespread in the Indo-Pacific.
Habitat: Lagoons in areas of bright light and
surge. Also on reef slopes or in sand adjacent
to reef.
Appearance: Medium- to large-sized colonies,
often bushy with large, slender, rounded
branches. Grey, light yellow or light brown.
Diet: Mainly products of their zooxanthellae.
One of the few Pacific gorgonians to have
zooxanthellae.
Remarks: While this genus is widely
recognized, more needs to determined about
its biology and systematics.
ORDER PENNATULACEA
(SEA PENS)
Giant Sea Pen
Ptilosarcus gurneyi (Pennatulidae)
Distribution: Gulf of Alaska to southern
California.
California Academy of Sciences
31
Habitat: Shallow subtidal to 70 m on sand and
mud substrates in areas of strong current that
aids feeding. Sessile, benthic. Often found in
large beds with many individuals.
Appearance: A primary polyp is modified
to form the body, which includes a base
that extends into the sediment and a stalk
(the rachis) that rises between the feathery
extensions. Large adults may extend 60 cm out
of the sediment with another 30 cm extending
into the substrate. Color from pale cream to
deep orange-red.
Diet: Filter-feeder on particulate organic
matter, larvae, and other small zooplankton.
Reproduction and Development: Each polyp
in the colony is either male or female; each
spawns its gametes into the water column
where fertilization occurs. Larvae eventually
settle on sand and metamorphose into a
founder polyp that becomes the stalk and from
which other colony polyps arise by asexual
proliferation.
Mortality/Longevity: Preyed upon by several
nudibranchs including Hermissenda crassicornis,
as well as various sea stars, including the
sunstar (Pycnopodia helianthoides) and the
leather star (Demasterias imbricata). May rapidly
burrow into sediment to avoid predation.
Remarks: Besides the primary polyp, sea pens
have other specialized polyps. Feeding polyps
with feathery tentacles can be seen on the
rachis or its lateral extensions. Embedded in
the rachis’ surface are “pumping” polyps that
use cilia to draw water into the colony’s body.
Cilia lining water channels work with larger
muscular contractions of the body to deliver
nutrients throughout the body.
Giant sea pens typically inflate when they
feed, and then deflate to a much smaller
size. Sometimes they completely bury in the
sediment.
Many sea pen species are extremely abundant,
forming vast fields on deep-sea abyssal
plains.