W
e’ve just arrived at the Neptune Islands at the mouth
of the Spencer Gulf, some 27 km south of Cape
Catastrophe, South Australia. It is desolate, and a
brutally cold wind is ripping through my body, which only
adds to my exhilaration. Pictorial accounts of the expeditions
of Rodney Fox and Ron and Valerie Taylor to the waters off
Port Lincoln have cultivated a passion I’ve had for as long as I
can remember – a fascination with white sharks (Carcharodon
carcharias). As the first dorsal fin breaks the surface, I feel a
surge of excitement that is shared with others aboard the
vessel. Tourists scramble for a first glimpse. I understand their
elation. My first cage-dive was a magical experience. I watched,
fascinated, as a female shark swam peacefully from the blue
distance towards the cage. As she glided past, I stared into her
eye, feeling as if this experience was occurring in a dream. Would
the participants on board today’s tour feel the same surreal
connection? Would their hearts be hammering every bit as hard
as mine?
There’s no doubt about it: these sharks result in big news,
and often in tall tales, too. Big-screen blockbusters like Jaws
and Sharknado have granted white sharks Hollywood notoriety
and reinforced their public image as man-eating machines.
This negative connotation has resulted in insufficient public
support, and has prevented the conservation management
white sharks desperately require. However, some people
have begun to challenge the stereotype. Changing public
perceptions of sharks from one of demonisation to one of
appreciation is where my interest lies.Long-distance swimmers
The white shark is considered the ocean’s largest predatory fish.
This formidable predator is capable of growing to more than 6 m
in length, weighing more than 3000 kg, and achieving speeds of
more than 60 km/h. In Australia, white sharks have been sighted
off the coast of all states except the Northern Territory. Known to
travel long distances, they can also spend periods of residency
at certain sites such as the Neptune Islands. Both adults and
juveniles venture several hundred kilometres offshore and can
dive to 1200 m. Most white shark movements, however, occur
between the coast and the 100 m-depth contour. They frequent
inshore habitats, such as rocky reefs, surf beaches and shallow
coastal bays.Little research has been conducted on these sharks’
reproductive cycle. Females are larger than males, but they are
slow to mature, taking more than a decade to reach breeding
maturity, which makes the species susceptible to population
decline. Gestation period alone is estimated to be up to
18 months, with a reported litter size of 2–17, although the
maximum number of near-term pups confirmed by dissection
of pregnant females is ten. This extended life history implies a
vulnerability to non-natural mortality and a low rate of recovery,
which has considerable implications for their conservation.US & THEM
RATTLING THE CAGE
Can an adrenaline-inducing experience teach us to appreciate the ocean’s apex predators and even
to champion their conservation? White shark enthusiast Kirin Apps is just the person to ask.CAVE-DIVING IS ‘SHAKING UP’ SHARK
CONSERVATION IN POSITIVE WAYS
The current scale of the threat to global
shark populations is enormous.
Photo: Calypso Star ChartersRATTLING THE CAGERATTLING THE CAGE
6 | Wildlife Australia | SPRING 2017