THE STEINHART AQUARIUM - Gulf of Guinea Science ...

92 A Docent Field Guide to the Species of the Steinhart Aquarium
star (Demasterias imbricata), some fish, and red
rock crabs.
Remarks: Looking more like a cross between
a chiton and a nudibranch, the creeping pedal
sea cucumber looks nothing like the typical
cigar-shaped sea cucumber.
Uses toxic chemicals to discourage predators
from preying on its tentacles.
California Sea Cucumber
Parastichopus californicus (Stichopodidae)
Distribution: British Columbia, Canada to Isla
Cedro, Baja California.
Habitat: Low intertidal in areas protected from
strong wave action; also on pilings in open
bays, and subtidally to 90 m deep.
Appearance: California’s largest sea cucumber
is 25–40 cm long; dark red, brown or yellow.
Diet: Deposit feeder; organic detritus and small
organisms ingested in bottom sediments.
Reproduction and Development: Breeding
occurs during the summer. Development is
indirect; fertilized eggs develop into several
different larval forms before settling.
Mortality/Longevity: Eaten by sea stars
including the sunflower star. Sea otters and
humans are also predators.
Warty Sea Cucumber
Parastichopus parvimensis (Stichopodidae)
Distribution: Monterey Bay to Baja California.
Habitat: Sandy or muddy-sandy soft bottoms
between rocks or in eelgrass beds, subtidal to
27 m depth.
Appearance: Length to 25 cm. Colored brown
above, lighter below. Conical black-tipped
papillae on the dorsal side provide the common
name.
Diet: Digests organic detritus and small
organisms in soft sediments.
Remarks: Sea cucumbers breathe through
special “respiratory trees” that branch
internally from the anus. Rhythmic muscle
contraction and relaxation forces water out,
then brings oxygenated water in
Certain species of pea crabs and scale worms
live as commensals within the respiratory
tree of our local cukes, taking advantage of a
protected space and small particles of food also
delivered by water exchange.
PHYLUM CHORDATA.
SUBPHYLUM VERTEBRATA
(VERTEBRATES)
CLASS ELASMOBRANCHII
(CARTILAGINOUS FISHES:
SKATES, RAYS AND SHARKS)
ORDER HETERODONTIFORMES
(BULLHEAD SHARKS)
California Horn Shark
Heterodontus francisci (Heterodontidae)
Bullhead and Horn Sharks
Distribution: Monterey Bay, California to the
Gulf of California.
Habitat: Solitary bottom dweller from intertidal
to 150 m deep. Inhabits rocky bottoms, kelp
forests, sandy draws between rocks, sand
flats, deep crevices and small caves as well as
large underwater caverns. Active nocturnally.
Sluggish during the day, often rests among rocks
with its head in a crevice. Adults tend to return
to the same resting place every day.
Appearance: Horn sharks have a short blunt
head with high ridges above the eyes and two
dorsal fins, each with a strong spine at the
origin. Color is light to dark brown above, with
small, scattered dark spots on the body and
fins. Spots may be faded or absent on adults.
Length to 1.2 m.
Diet: Nocturnal predator of benthic invertebrates,
especially sea urchins, crabs and probably
abalone, also fishes. Horned sharks have 2
different types of teeth (heterodontus = “different
teeth”); front teeth have sharp cusps for seizing
prey, rear teeth are molariform for crushing
crab shells. Juveniles may eat worms, and have
been observed eating club-tipped anemones
(Corynactis californica). One author noted that
the horn shark’s predilection for red sea urchins
may result in the shark’s teeth being stained a
reddish brown.
Reproduction and Development: Like all
sharks, fertilization is internal. The male horn
shark holds the female by grasping one of her
pectoral fins with his mouth and then maneuvers
his tail around her so he can insert one
of his pair of claspers. Horned sharks mate