Meanings
of [swollen] carcasses or cadavers and [bulged] objectsin a position with the belly or underside facing upwards; belly up/belly-up, (by extension, figurative) upside down
Translation: 1980, Günter Grass: The Flounder. A novel. New York: Fawcest Crest, (GoogleBooks; retrieved October 15, 2015), page 85:The herring and flounder had stayed away, too, and the fish perished in the rivers as if the country had been cursed: perch, bass, roach, and pike were seen drifting belly up.
zumeist von (aufgequollenen) Kadavern und (gewölbten) Gegenständenbelly up belly-up )
„Auch die Heringe und Flundern waren weggeblieben, und in den Flüssen zeigte sich, wie durch Fluch befördert, ein Fischesterben an: Zander, Barsche, Plötze und Hechte trieben bauchoben.“