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WINTER 2016
LIFE AQUATIC
SAND TIGERS
are around 3 feet long at birth; the average length for
adult males is 8 feet, while females max out at around
10 feet and 350 pounds.
Sand tigers tend to mate in late winter to early spring.
The male shark will bite the female on the pectoral fin
to latch on during the mating process. Each year in May,
at the beginning of the dive season in North Carolina,
many females are seen sporting grizzly wounds. But the
sharks are fast healers. Come July the wounds are mostly
healed with only faint scars remaining.
Every two or three years, after a gestation period of
eight to 12 months, females typically give birth to one or
two pups, typically one from each of her two uteri. These
young sharks are frequently seen on the wrecks and are
easy to approach. This small number of births is due to
the fascinating but macabre phenomenon of intrauterine
cannibalism, in which the larger and stronger fetuses
consume the lesser ones. A pregnant female may start
off with as many as 40 embryos but give birth to just the
one or two pups. Hence, sand tiger sharks obtain their
hunting instincts even before birth. The disadvantage of
this is that sand tigers have one of the slowest rates of
reproduction of any shark species. When their numbers
are down it takes longer for them to rebound.
Overfishing of sand tigers has caused their numbers
to plummet worldwide. In the 1970s and ’80s in
Australia, divers purportedly used explosive powerheads
to kill sharks for sport. Because of how easy it is to
approach sand tigers, little skill was involved in this
style of fishing, and the results were devastating. In
the United States, recreational fishermen as well as
commercial longliners and purse seiners often caught
sand tigers unintentionally. Considered a “trash fish,”
sand tigers caught as bycatch usually died. These and
other unchecked and destructive fishing practices took
a toll on sand tiger shark numbers to the point that they
became a protected species in Australia, South Africa
and the United States in 1997. Today they are listed as
vulnerable on the International Union for Conservation
of Nature and Natural Resources (IUCN) Red List of
Threatened Species.
The answer to whether sand tiger numbers are
increasing depends on who you ask. “I do not have any
scientific evidence, but I do believe sand tiger shark
populations might be on an upward trend,” said Chris
Paparo, manager of the Marine Sciences Center at the
Southampton campus of Stony Brook University. “In
recent years, anglers targeting fluke or striped bass
have been catching both adult and juvenile sand tiger
sharks with greater frequency.”
Recreational divers who have been diving North
Carolina’s wrecks for more than 25 years also report
seeing more sand tiger sharks now then ever before.
“Shark numbers may be stabilizing, but to say they are
increasing may be a stretch,” Fessler countered. “There
are more eyes in the water today looking for sharks
than there were 25 years ago; in turn more sharks are
being seen.”
Based on what I have witnessed over the past 15
years, I believe shark numbers are slowly on the rise.
I’m seeing sharks on wrecks where they were rarely
seen before and with more regularity. Regardless of
whether their numbers are increasing or not, sand
tiger sharks, like all marine apex predators, require
continued protection. The health of the ocean
ecosystem, on which we are dependent for fish stocks,
starts at the top of the food chain. Abundant sharks
equates to abundant marine life. It’s no coincidence
that when we see the greatest numbers of sharks on
wrecks we also see large gatherings of other fish such
as Atlantic spadefish, grouper, jacks and flounder.
When I was a dive boat captain in North Carolina,
each morning before departure I would ask the divers
where they wanted to go. Most would say without
hesitation, “We want sharks!” There was no need to
twist my arm; a few minutes later we would be under
way to wherever the hot spot for sand tigers was at
the time. The wrecks of the
Caribsea, Proteus, Atlas,
Aeolus,
USCGC
Spar
and
W.E. Hutton
(also known
as the
Papoose)
are some of the famous sand tiger
haunts that were often at the top of the hit list. As
long as Mother Nature cooperated enough to allow us
to venture offshore, we could pretty much count on
outstanding shark diving.
As divers walked down the dock at the end of a
successful day of shark encounters, I could tell I
was going to see many of them again soon. It was
apparent these divers had been bitten — not by a
shark but by a bug: Sand tiger shark diving is highly
contagious.
AD
The
Atlas
tanker’s mazelike remains are a perfect
backdrop for photographing sand tiger sharks.