THE STEINHART AQUARIUM - Gulf of Guinea Science ...

during December and January; egg cases are
laid from February to April. The large (length
12 cm) brown egg case is screw-shaped with
a broad flange spirally twisted around it.
Egg cases are scattered among rocks and in
crevices. The pup emerges 7–9 months later
as a miniature (16 cm) shark.
Mortality/Longevity: Long-lived, up to 25
years.
Conservation Status: Not on IUCN Red List.
Commercial catch is used to produce fish meal;
fin spines used in production of jewelry.
Remarks: Can clamber on substrate with
flexible pectoral and pelvic fins.
Horn sharks typically spend daylight hours in
one spot, usually a cave or crevice. True to their
nocturnal habit, our specimens are often out of
view during Aquarium hours.
ORDER CARCHARINIFORMES
(GROUND SHARKS)
Swell Shark
Cephaloscyllium ventriosum (Scyliorhinidae)
Catsharks
Distribution: Central California to southern
Mexico; also reported near central Chile.
Habitat: Rocky reefs and kelp forests, from
surface to 460 m, in temperate and subtropical
waters.
Appearance: Stout body with flat, broad head;
snout short; mouth huge, proportionally
larger that the great white shark (Carcharodon
carcharias).
Diet: Active at night; feeds on crustaceans and
fishes, often blacksmith. Lie-in-wait predator
that sits on the bottom with wide-open mouth,
ready to ambush unsuspecting prey.
Reproduction and Development: Female
lays amber-colored egg cases that hatch in
8–10 months. Young have enlarged toothlike
denticles on the back that help them break
through egg cases.
Mortality/Longevity: Embryos may be eaten
by snails that bore through egg cases.
Conservation Status: Numbers declining
along the California coast, perhaps due to
changes in sea temperature.
Remarks: Hides in caves and crevices during
the day, and so is often not to be seen during
California Academy of Sciences
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normal aquarium hours.
Common and specific (ventriosum = “large belly”)
names come from its ability to take in water that
makes it appear up to twice as large as its normal
size, a difficult meal for predators to bite or to
remove from a crevice. If caught and brought to
the surface, it can swell its body with air.
Leopard Shark
Triakis semifasciata (Triakidae)
Houndsharks
Distribution: Oregon state to Baja California
and northern Gulf of California.
Habitat: Prefers sandy and rock-strewn substrate
near rocky reefs. Most commonly in
enclosed muddy bays, including estuaries and
lagoons, typically at less than 3.7 m depth, but
ranges to 91 m.
Appearance: Grayish with bronze tinge above,
white below. Broad black bars, saddles and
spots on dorsal surface; saddles solid in young,
with light centers in adults. Adults have more
spots. Males to 2 m; females slightly larger.
Diet: Fishes (especially northern midshipman,
sanddab, shiner perch, bat rays and smoothhounds),
siphons of clams, crustaceans such as
crabs and shrimp. Feeds heavily on fish eggs
(herring, jacksmelt and topsmelt) attached to
rocks and plants.
Reproduction and Development: Ovoviviparous.
Litters 4–29. Young average 21 cm at birth.
Mortality/Longevity: Can live to at least 30
years. Part of the commercial shark fishery and
very popular as a sport “fish.” Preyed upon by
other sharks.
Conservation Status: This mid-sized coastal
shark is fairly common in bays and estuaries
of the eastern North Pacific from California to
the northern Gulf of California, Mexico.
Remarks: Often in schools with other houndsharks
Nomadic; schools may visit an area
briefly, then depart.
Most research on this species has been conducted
in the SF Bay; thus there is a tie-in with
the Academy’s Bay2K project.
In SF Bay, leopard sharks tend to remain in the
Bay throughout the year, with some emigration
during fall and winter.
Fossils of leopard sharks have been discovered
in deposits dated to more than 1,000,000 years
old in southern California.