Longlines: baited hooks on lines
varying in length from 15 to 100
kilometers set with floating buoys or
sunk with weights depending on the
targeted species. Sea lions, fur seals,
toothed whales, and other marine
mammals can get caught on the
hooks or tangled in the lines.
Gillnets: mesh nets that can be set on the sea floor or floated in
the water column depending on the targeted species. Marine
mammals that dive for food around gillnets tend to become
entangled and drown when they are unable to surface for air.
Trawls: funnel-shaped nets that are dragged behind boats at
different depths, depending on target species. Marine mammals
are attracted to trawls, which they become entangled in, because
they often target the species that mammals prey upon.
Purse seines: nets that hang
vertically in the water column
using weights at the bottom
and buoys at the top. They can
enclose marine mammals in
the nets, along with fish.
Bottom-set traps: (commonly called “pots”) crustacean traps with ropes
that connect them to surface buoys and to one another. Large whales are
particularly prone to getting entangled in the ropes, which wrap around
their bodies, making it difficult for them to move or feed.