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 spawn from February to May, with an April peak in the Gulf of Maine and an earlier onset and peak in the Mid-Atlantic Bight. Tagged winter flounder south of Cape Cod appeared to seek cold temperatures in deep water during summer, whereas winter flounder in the colder Gulf of Maine do not.