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.
Southern flounders eat a wide variety of food items, including shrimp, mullet, anchovies, croakers, and menhaden (pogies). One research project in Texas reported southern flounders to be the dominant fish predator on brown shrimp during the spring in Galveston Bay.