A gang of thugs cruises through again
terrorizing the neighborhood at every turn.
They are the jacks or trevallies as they are also known.
Meeting a school of jacks is a frightening life death experience for
other fishes on the reef so they hide away hoping to escape unnoticed. For Jacks the entire reef is their
playground. They’re not tied down to a particular patch or territory like many
other of the reefs inhabitants. They have a free rein and cruise around often in
groups the sunlight glinting off their silvery sides.
Jacks are among the most efficient fish hunters on the coral reef. Their
streamlined shape and reinforced bony tail make them speed machines.
A favorite trick is to plunge into a school of small fishes scattering them
in all directions. Once a school is separated and attack is
much more simple. Sometimes a whole group of jacks will
dash into a school picking off the confused and disorientated fishes as
they go. Other jack species hunt for
bottom-dwelling fish or invertebrates either by following species that rummage
in the substrate or sifting through the sand to find food for themselves.