Page 58 - BBC Focus - August 2017

EARTH

LIZARDFISH
Two menacing lizardfish were collected on the trip, from a depth of 2,500m (1.6
miles). “It has just nasty, nasty teeth,” says Bray. Huge eyes help them detect the
faint glow of bioluminescence, which is a form of light made by many marine
animals. Lizardfish are hermaphrodites, which means they have both female
and male sex organs. This is a great reproductive strategy in the vastness of the
deep sea, as the fish don’t have to worry about finding a partner of the opposite
sex when they want to reproduce – any member of the same species will do.

GELATINOUS CUSK EEL
This fish lives in the permanent dark and has tiny eyes that may not work well.
Yet somehow, it finds mates in the inky depths and gives birth to live young. The
research team found another cusk eel species, which they nicknamed the
‘faceless fish’. But it turned out not to be new to science. The species had
previously been collected 140 years ago in the northern part of the Coral Sea, on
the historic voyage of the British ship HMS Challenger, the world’s first
round-the-world oceanographic expedition. The new specimen is already on
display to the public at Museums Victoria.
COOKIECUTTER SHARK
These fearsome sharks are rarely seen alive, but are mostly known from the
circular wounds they leave in their prey (hence their name). They spend their
days in the ‘twilight zone’, 1,000m down, then rise up at night to hunt in
shallower waters. The sharks measure about half a metre in length, and latch
onto large fish, dolphins and whales, before slicing out a plug of flesh with their
razor-sharp teeth. Cookiecutters glow in the dark, which eliminates their
shadow in the dim blue light of the twilight zone. A dark band on their skin may
fool their victims into thinking they’re smaller prey fish, which lures them
within striking distance.
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