THE STEINHART AQUARIUM - Gulf of Guinea Science ...

Diet: Oral “winnowers” sifting out thin-shelled
invertebrates from the substrate; occasionally
eat mollusks and algae.
Reproduction and Development: Like all
surfperches, are viviparous with young highly
developed and free-swimming at birth.
Remarks: Overall population decline. Small
commercial fishery in Southern California;
most caught by sport fishermen who seek out
the larger, mature females.
Pile Surfperch
Rhacochilus vacca (Embiotocidae)
Surfperches
Distribution: Southeastern Alaska to north
central Baja California.
Habitat: Rocky shores, pilings, kelp beds,
underwater structures to 46 m.
Appearance: Length 25–30 cm; maximum 42
cm. Silvery sides; deeply forked caudal fin.
Diet: Hard-shelled mollusks, crabs and
barnacles.
Reproduction and Development: Live bearer.
Fecundity increases with age, averaging from
11–60 young.
Mortality/Longevity: 7–10 years.
Remarks: Specialized pharyngeal dentition
that enable pile perch to crush hard shells
persuades some ichthyologists to place the
species in its own genus (Damalichthys).
Clark’s Anemonefish
Amphiprion clarkii (Pomacentridae)
Damselfishes
Distribution: Indo-Pacific: Persian Gulf to
Micronesia, New Caledonia and Fiji. Also
Southwest Japan to northern Australia.
Habitat: Depth 1–55 meters in outer reef slopes,
less typically inhabit lagoons. Symbiotic with
10 species of sea anemones. Non-migratory.
Appearance: To 12 cm. Black to entirely
orange with pair of white or pale blue bars.
Second bar wide; tail white or yellowish;
other fins variably black to yellow-orange.
There is also an orange variation: some are
entirely pale orange, other than the two white
bands; others have a dark patch on rear body.
(See remarks)
Diet: Primarily planktonic copepods and
benthic algae.
Reproduction and Development: Members of
California Academy of Sciences
163
the genus are monogamous; oviparous, benthic
spawners. Parents create a nest and male
guards eggs. All are protandrous hermaphrodites
with one sexually active pair dominant
over a group of juveniles. If the female dies,
her male partner develops into a female to
take her place, and the largest juvenile grows
rapidly and sexually matures into the breeding
male. The maturation of the smaller juveniles
is stunted by the adult pair’s presence.
Remarks: Coloration is apparently influenced
by the host sea anemone species.
Symbiotic with several anemones found in
the Steinhart including Entacmaea quadricolor,
Heteractis crispa, H. magnifica.
False Clownfish aka Nemo
Amphiprion ocellaris (Pomacentridae)
Damselfishes
Distribution: Tropical Pacific Ocean.
Habitat: Coral reefs. Sleep and feed among the
tentacles of their host anemone.
Appearance: Length to 9 cm. Adults are orange
with three broad vertical white bands, thin black
margins on fins. Female larger than male.
Diet: Primarily zooplankton, especially copepods,
also filamentous algae.
Reproduction and development: Breeds continuously
at the Steinhart. Adhesive eggs are laid on
a patch of cleared rock near the host anemone’s
base and guarded by the male. Eggs hatch after
10 days. The tiny transparent planktonic larvae
swim away from the anemone. Two weeks later
the larvae metamorphose into small fish. Protandrous
hermaphrodites; some individuals mature
as males, and all females are sex-reversed males.
In the absence of a female the breeding male will
turn into a female.
.Remarks: Often confused with Amphiprion
percula, A, ocellaris is the true Nemo of Finding
Nemo fame.
That said, Marlin, Nemo’s father, under natural
conditions, would have changed into a female
following the death of Nemo’s mother and
remained near his host anemone, rather than
swimming to Sydney. But then the film makers
wouldn’t have had a heart-rending narrative
for the film.
The name “Nemo” has found its way into
FishBase (www.fishbase.org) as a common
name for this species in the USA!