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For the computer malware spying operation, see
Sea turtle entanged in a ghost net
Ghost nets are fishing nets that have been left or lost in the
ocean by fishermen.
These nets, often nearly invisible in the dim light, can be left
tangled on a rocky reef or drifting in the open sea. They can
entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, seabirds, crabs, and other creatures, including the
occasional human diver.
Acting as designed, the nets restrict movement, causing
starvation, laceration and infection, and — in those that need to
return to the surface to breathe — suffocation.
Some commercial fisherman use gillnets. These are anchored to the sea floor
with floatation buoys along one
edge. In this way they can form a vertical wall hundreds of metres
long, where any fish within a certain size range can be caught.
Normally these nets are collected by fisherman and the catch
removed. However if this is not done the net can continue to catch
fish until the weight of the catch exceeds the buoyancy of the
floats. The net then sinks, and the fish are devoured by
bottom-dwelling crustaceans and other fish. Then the floats pull
the net up again and the cycle continues. Given the high-quality
synthetics that are used today, the destruction can continue for a
The problem is not just nets; old-fashioned crab pots, without the
required "rot-out panel", also sit on the bottom, where they become
self-baiting traps that go on catching crabs year after year. Even
balled-up fishing line can be deadly for a variety of creatures,
including birds and marine mammals. Over time the nets become more
and more tangled. In general, fish are less likely to be trapped in
gear that has been down a long time.
The French government offered a reward for ghost nets handed in
to local coastguards along sections of the Normandy coast between
1980 and 1981. The project was abandoned when people vandalised
nets to claim rewards, without retrieving anything at all from the
shoreline or ocean.