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.
Flounders ambush their prey, feeding at soft muddy areas of the sea bottom, near bridge piles, docks and coral reefs. A flounder's diet consists mainly of fish spawn, crustaceans, polychaetes and small fish. Flounder typically grow to a length of 22â60 centimeters (8.7â23.6 in), and as large as 95 centimeters (37 in). Their width is about half their length.