Many fish leap to escape from danger below, and fishermen have developed all kinds of clever gear to take advantage of this. After all, if the fisherman’s goal is to remove fish from the water, seeking leaping fish gives him a great head start.
The species most apt to leap (other than salmon at waterfalls) is mullet, a rather cosmopolitan fish. Around the world, fishermen have invented ingenious ways to pluck jumping mullet. The simplest of tricks often was used in Lake Vrana, Yugoslavia.
A small boat was fixed slightly obliquely across the lake’s outlet. Mullet ascending from the sea would encounter this barrier, attempt to vault it, and in the process, land in the boat, ready for delivery.
Over much of the Mediterranean, Black, and Caspian Seas, jumping mullet were caught using rafts of reeds. On a moonlit night mullet saw the shadow cast by a raft floating on the water surface and appeared to perceive it as an obstacle, so they would try to leap over it.
But the rafts made to catch fish were wide enough (four to twelve feet) that the airborne mullet would not clear them and would up flopping on top. To prevent them from wriggling back into the water, the edges of the rafts were bent upward. Sometimes brushwood and netting also were used to entangle the fish.
In England, a ruse was used to keep mullet that had been corralled from leaping out of the net. By breaking up a bale of hay so that the floating “headline” of the net was buffered by a couple of feet of floating straw, any mullet leaping would take off too soon, thereby landing within the net’s confines.
The Chinese designed an especially sophisticated method of catching leaping fish. They suspended a net wall from stakes below and above the water. On both sides of the emergent portion of the net hung net bags conveniently poised to catch fish that bounced off the net wall.
Perhaps there is good reason that we define helplessness as “a fish out of water.”