A live car ( a box shaped net with an open top) is attached to a seine. as the seine is pulled through the pond the fish are funneled into the live car. when the seining is complete the live car can be detached and used for holding the fish. fish are often left in the live car for several hours so that the smaller fish can escape through the mesh holes in the net. this is called grading. depending on what size fish are desired farmers use live cars with different mesh sizes. some live cars can hold up to 100,000 pound of fish.