Wiktionary(0.00 / 0 votes)Rate this definition: upthrust(Noun) an upward thrust. upthrust(Noun) buoyancy. upthrust(Noun) an upward movement of part of the Earth's crust. upthrust(Verb) to thrust something upwards.
Predators, Food and Feeding: Natural predators of winter flounder include sharks, oyster toadfish, summer flounder, striped bass, monkfish and spiny dogfish. When feeding, a winter flounder will lie motionless, partly concealed on the bottom, with its head raised off the bottom, braced by the dorsal fin.
Winter Flounder Adults. Winter flounder (Pseudopleuronectes americanus) are right-eye flatfishes (Family Pleuronectidae). They may look flattened on the belly, but are actually flat sideways and lying on their left side, with both eyes together on the right side of the head. The left (blind) side, pressed against the sea floor, usually stays white.