To those unfamiliar with the day to
day patterns and behavior of sharks, it seems almost unfathomable
that anyone would willingly put one's self close to them. This,
however, is precisely what our passengers do every week. People
have been diving with sharks in the Exumas since 1992 without any
incidents. There are no records of divers being bitten in the Bahamas
other than those that tried to grab or touch a shark, were spearfishing
or were hand-feeding sharks. To keep our shark dive safe for both
customers and crew, we lower a frozen chumsicle from the surface
so that no humans get near the food. The primary sharks we have
on our dives are Caribbean reef sharks and nurse sharks. Tom Wilson
of Sandy, UT shot the video at right. (It gives you an idea of what
our shark dive is like.) Experience the shark dive.
(1.7 MB - 14 Seconds)
While humans are seldom at risk
from shark attacks, sharks are under serious threat from humans.
Shark populations have suffered large declines because of humans.
The demand from Asia for shark fins traditionally used for making
soup, has led to the slaughter of many sharks by fisherman. The
fishermen remove the fins and discard the rest of the body. A
typical shark takes 3-4 years to reach sexual maturity at which
time she gives berth to 1-4 pups per year. Less than 25% of these
pups reach sexual maturity. If something isnt done soon
to protect sharks, their decline
may
become irreversible. (Shark feeding dives in the Bahamas have
helped to educate people about the threat sharks face.) Several
years ago, after long-line fishermen slaughtered over 50 sharks,
the Bahamas passed laws prohibiting this practice. Recently the
Bahamian government has moved to establish no fishing zones around
many of the feeding sites.
Shark Identification
Historically, sharks
left the area when scuba divers entered the water. The bubbles
from the regulators scare them off. Since shark dives started
in the Bahamas many of the sharks have lost their fear of these
bubbles. Has that made them more aggressive towards divers? No,
but your chance of seeing a shark on a non-shark dive has increased
greatly. Instead of diverting their course several hundred feet
away from you, they now continue their planned course that frequently
brings them close enough to be seen. This is a list of the sharks
that have been seen on our trips:
Caribbean Reef
Shark (Carcharhinus perezi)
They are the most common
sharks and cruise the offshore reefs. The caribben reef shark
is the primary shark on the shark feeding dive.
They range in length from 5
to 8 to 10.
The tips of their fins and the
lower lobe of their tail are dusky. The blacktip shark also has
dusky tips, but its anal fins are pale to white.
The first dorsal fin is relatively
small and begins behind the pectoral fins.
Little is known about the Caribbean
reef sharks biology. Females bear 4 to 6 pups per litter.
It primarily feeds upon fish.
Nurse Shark
(Ginglymostoma cirratum)
During the day they are normally
found sleeping on the bottom under ledges. They are one of the
few sharks that have the ability to bite its tail. Because they
look harmless, divers have been known to grab them by the tail,
causing the nurse to turn and bite its tormentor. This has
made the nurse shark the most common shark involved in human shark
attacks. Fortunately it has very small teeth and the bites are
seldom serious. On our shark dives the nurse sharks like to harmlessly
cuddle up to divers.
They range in size from 5
to 9 with a maximum of 14. They have two barbells
on their upper lip. Both of their dorsal fins are approximately
the same size and are set far back on their body. They lack a
noticeable lobe on their tail.
It feeds primarily at night on
bottom-dwelling invertebrates, such as lobster and other crustaceans.
Mating is in the spring. During
this time, the female swims into shallow water to avoid mating
with undesirable males. The males bite onto her pectoral fins
and try to drag her into deeper water to mate. She finally submits
when she decides the male is desirable. There are several areas
in the Exumas where nurse sharks are known to mate.
Silky Shark
(Carcharhinus falciformis)
Schools of juvenal silky
sharks are frequently seen in the summer at the blue hole and
at the offshore sea buoy. They leave both of these sites in the
fall. It is not known where they go. Silkys are normally open-water
sharks. The females reach sexual maturity at a length of 7.
They give birth to 6 to 14 young.
Adults range in size from 5
to 7 with a maximum of 10. The sharks we see range
from 2 to 3. Their first dorsal fin is relatively
small, rounded and starts behind the pectoral fins. Their second
dorsal fin is small and has a long trailing edge.
Scalloped Hammerhead
(Sphyma lewini)
Divers occasionally see scalloped
hammerheads swimming over the reefs or along the walls. The unusual
video at right was shot during one of our shark dives. Females
bear from 15 to 30 pups, each 17" to 22" long.
Adults range from 5 to 9,
with a maximum length of 14. The front edge of the hammer
has a scalloped look. The inside tip of the pectoral fins are
dark.
Whale Shark
(Rhincodon typus)
Whale sharks are seen only
in winter. Some winters we dont see any and other years
they are seen most weeks. It is the worlds largest living
fish. These gentle creatures dont seem to mind divers approaching
them. While most people think they are only a plankton eater,
they frequently eat fish as large as tuna. We recently observed
this behavior when a whale sharks mouth broke the surface
in the middle of a school of feeding tunas. Its body was perpendicular
to the surface with its tail straight down. It stayed in this
position waiting for tuna to jump into its mouth.
Whale sharks range from 20
to 45 with a maximum length of 55. They are covered
by large white spots. The females give live berth to as many as
several hundred young.
(1.7 MB - 20 Seconds)
Lemon Shark
(Negaprion brevirostris)
Lemon sharks are known to
breed at several locations in the Bahamas including the Exumas.
The young lemon sharks stay in the shallow waters around mangroves
and in the grass beds until they are about 5 long. They
swim the same route every day. Until recently, we had two that
swam by the park headquarters every day at the same time. They
are also seen in the creeks at Shroud Cay.
Lemon sharks range from 5
to 8 with a maximum of 11. Their second dorsal fin
is almost as large as the first. They have a short, blunt, rounded
snout. They feed upon bony fishes, rays, crustaceans and mollusks.
Females reach sexual maturity at 8 in length. They mate
in the spring and summer and give berth to between 4 & 17
live young one year later.
Atlantic Sharpnose
Shark (Rhizoprionodon terraenovae)
The sharpnose shark is a
very shy shark that inhabits the shallow coastal waters. If you
are lucky enough to see one, it is likely to be as it swims away
rapidly. It is a common prey for larger sharks.
Sharpnose sharks range from 2
to 3 with a maximum of 3 _ . They have a long flattened
snout. Their second dorsal fin begins above the middle of the
anal fin and is much smaller then the first. Adults usually have
a few scattered spots on their back. Their gestation period is
from 10 to 11 months with a litter of 2 to 6 pups, each about
1 long. They feed upon small fish and invertebrates such
as shrimp and snails.
Tiger Sharks
(Galeocerdo cuvier)
Although the tiger shark
is considered to be one of the most dangerous sharks, they tend
to swim away from divers. Our few sightings have been of sharks
in the distance.
Tiger sharks range from 7
to 12 with a maximum of 24. Their lifespan is estimated
at 50 years. They have dark blotches on their body. They will
eat almost anything with their most common food being turtles,
sharks and seabirds. They have a reputation for being the garbage
cans of the seas. They have been found with the following in their
stomachs: license plates, grass, tiles, cardboard, ropes, shoes,
barrels, tin cans, bottles and a birth control container. They
give birth to between 12 and 80 pups after a gestation of 12 months.
Rays
Although most people
dont realize it, rays are also in the same family as sharks.
We commonly see three types of rays; spotted eagle rays (Aetobatus
narinari), southern stingrays (Dasyatis americana), and yellow
stingrays (Urolophus jamaicensis). Manta rays (Manta birostris)
have been seen by a few lucky divers but are very rare in the
Bahamas.