White perch is a fish that is native to atlantic coastal regions and is invasive to the great lakes. it feeds on native species and is thought to be the cause of the decline of the great lakes walleye fish populations. what was most likely its mode of introduction? produce brought from the eastern states trapped in a ship's ballast or a water tank trapped in a cargo crate carrying nonperishable items luggage brought in an overseas flight

ANSWER:  Trapped in a ship's ballast or water tank.

REASONING:  There are many examples of species being transported in the ballast or water tank of ships.  Ships need to be stable so they don't turn over.  Stability is provided by weight in the bottom part of the ship called the ballast.  This weight often comes from water that is stored in water tanks or the ballast area of the ship.  Water is taken in to the ballast at the beginning of its voyage.  When it arrives at it's destination, the ballast water is often drained.  Anything living in that water will also be drained in to the new location.  This is how species like the white perch can be introduced into new areas.

Trapped in a ship's ballast or water tank.

Explanation:

that's the only logical way a fish could make itself into the lakes.