Above: Blacktip shark. Opposite page: Tiger shark.
improve the gene pool among fish populations by preying on
sick and weak members. Their mere presence can intimidate
other species such as sea lions and turtles and prevent them
from overgrazing on beneficial seagrasses. Also, deep sea
sharks who scavenge on the ocean floor for food help to
move carbon throughout the water, enabling the sea to more
efficiently absorb it from the air. Sharks even help to protect
reefs. By keeping down the number of predators of small
herbivorous fish they prevent the overgrowth of algae,
which can cause reefs to die.
Sharks are distinctive in other ways, as well. Unlike most
fish, sharks (along with skates and rays) have skeletons made
of cartilage, which is lighter and more flexible than bone.
Their mouths contain several rows of teeth. When individual
teeth fall out (or get left behind in prey), new ones grow in to
replace them. Though all sharks share these traits, the shark
population is also incredibly diverse and contains hundreds
of species. These species range in size from the tiny dwarf
lantern shark, which measures only six inches to the whale
shark, which is 46 feet long!
Some species of sharks reproduce by laying eggs; others
give birth like mammals; while yet another group uses a
combination of methods with eggs hatching inside the
mother before they are born. Newly born or hatched baby
sharks are fully developed, and parents take no part in caring
for their young. Local estuaries, including the Charleston
Harbor and the North Edisto River near Seabrook, provide
nurseries for baby sharks of a variety of species. These areas
are critical to shark populations since they are the center of
near-shore shark breeding in the Southeast.
In South Carolina, summer brings the most substantial
number of sharks to our waters. The most common species
found here is the blacktip. These are the sharks you are most
likely to spot in the surf since they like to follow schools of
fish. Other common sharks found here in the summer include
tiger sharks (the largest of the group, they average between
SUMMER/FALL 2018 • VOLUME 40
10 and 14 feet long and 850–1,400 pounds); bull sharks
(which can survive in both salt and fresh water); lemon
sharks (which love to live in groups); and the hammerheads
(whose name says it all). Researchers have even discovered a
new species in our area—the South Carolina hammerhead.
Recent studies have shown that in the last few years some
of the species that summer in our region, particularly the
blacktip, have been arriving from their winter homes in
Florida earlier in the season and staying later—coming at the
end of February instead of April and leaving in November
rather than October. Scientists believe this may be due to
rising water temperatures in our area.
Unfortunately, the number of some types of sharks has
been dramatically decreasing. In the North Atlantic, the
population of several species of large sharks has declined
between 50 and 75 percent within the last eight to 15 years.
Their loss has been changing the ecosystem, increasing the
number of their prey and causing substantial declines in other
sea life, including commercially valuable scallops and clams.
The demand for shark fin soup, as well as the inadvertent
capture of sharks in fishing nets, has played significant roles
in their decline. Hopefully, conservation efforts currently
underway can prevent the extinction of these magnificent
predators. NK
Above: Bull shark. Below: Hammerhead sharks.
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