Page 70 - BBC Wildlife Volume 36 #06

some sharks assume the role of leaders and always swim Top: mangrove
at the front, while others are followers and seem content shallows are free
from big predators
to trail along behind.
so are ideal spots
As well as sticking with sharks they know, most young for young lemon
lemon sharks stay in one small area of mangroves – sharks to learn
perhaps just a few square kilometres – for the first three to hunt. Right:
finding suitable
years of their life. They never willingly stray too far. “If
food can be hit
you move a newborn lemon shark and take it way up
and miss. Below:
the coastline and release it in a completely new area, it the sharks’
will swim right back to its home,” says Ian Bouyoucos, hunting instinct is
a shark biologist who studied lemon sharks at the Cape there from birth.
Eleuthera Institute in the Bahamas. “They’re very much
attached to specific habitats,” he says.
HOMING SHARKS
An exception to these home-loving young ones are the
lemon sharks that live off the south-east coast of the
USA. Each winter, juvenile sharks hang out in an estuary
at Cape Canaveral in Florida. Then from February to
April they swim hundreds of kilometres northwards, to
estuaries in Georgia and South Carolina. It’s thought they
undergo these migrations to stay within their preferred
temperature range: not too hot and not too cold.
Back in the Bahamas, the lemon sharks retain their
homing abilities throughout their lives. As they get older
they gradually expand their home range, roaming an ever
larger area of the coast. Then as adults, at up to 3.4m in
length, lemon sharks set off on great journeys. Fitted
with satellite tags, they have been tracked thousands of
kilometres. But when the time comes for females to give
birth, they go right back to where they came from.
70 BBC Wildlife June 2018