478 BULLETIN OF THE BUREAU OF FISHERIES 



The history of the halibut fishery leaves no doubt that this species shows the 

 effect of hard fishing sooner than most sea fish, it being possible to catch up the 

 majority of the stock on any limited area in a few years, and so thoroughly and 

 constantly do the cod and haddock line trawlers search all the good fishing bottoms 

 of the Gulf of Maine and its banks that halibut never have a chance to reestablish 

 themselves in any abundance on the shoaler grounds. They maintain their numbers 

 better on the deeper slopes chiefly because they are subject to less intensive perse- 

 cution there, for it is only while and where halibut are plentiful enough to yield 

 paying fares that vessels fish regularly in such localities. 



The surface is the upper limit for the halibut, as we have just noted, while 300 

 to 350 fathoms may be set as the lower boundary to their existence in any numbers, 

 but the absolute depth limit is not known. It is sufficiently established that on the 

 whole large halibut keep to deeper water than small ones, a fact early noticed on 

 Georges Bank where the fish taken on the shoaler bottoms were all small (125 to 

 180 pounds), much larger ones being caught on the deeper slope to the southeast, 

 and this rule holds equally for the other side of the Atlantic. The halibut, like all 

 flounders, is normally a bottom fish, although it comes to the surface on occasion 

 (p. 477). It is usually found on sand, gravel, or clay, not on soft mud or on rock 

 bottom. 



Food. — The halibut is very voracious, preying chiefly on other fishes, a long 

 list of which have been reported from halibut stomachs, among them being cod, 

 cusk, haddock, rosefish, sculpins, grenadiers, silver hake, herring, launce, capelin, 

 flounders of various sorts (these seem to be its main dependence), skates, wolffish, 

 and mackerel. It is also known to eat crabs, lobsters, clams, and mussels. Even 

 sea birds have been taken from halibut. 50 Fishermen have reported finding in 

 halibut caught nearby, the heads and backbones of cod thrown overboard while 

 dressing down, and a variety of indigestible objects such as pieces of wood or iron 

 and even a fragment of drift ice. In any given locality the diet of the halibut 

 depends on what other ground fish are most easily available. Thus they are re- 

 ported to feed chiefly on flatfish on Georges Bank and on cod, haddock, cusk, and 

 sculpins on other grounds. Halibut, like other flounders, must be nearly invisible 

 as they lie on bottom, capturing their prey by a sudden rush after any fish that 

 passes within reach. Due to their great size and activity they are very destructive 

 to smaller fishes. We read, indeed, of half a bushel of flatfish taken from one halibut, 

 and of old, when they were so plentiful on the shoaler banks, fishermen said the 

 appearance of a school of halibut soon drove away the cod and haddock. The 

 halibut in turn falls prey to seals and especially to the Greenland shark, for which 

 it serves as a staple article of diet. 



Habits. — Little is known of the movements of the halibut except that its young, 

 like other flounder fry, swim near the surface for some months after hatching 

 (how long is not known), to take to the bottom at a length of 4 to 5 inches. The 

 older fish have often been credited with extensive journeys from bank to bank or 

 from deep to shallow water and vice versa, and they certainly rove the bottom in 



'° Sniitt (Scandinavian Fishes, 1892) speaks of a halibut that had eaten a razor-billed auk; Qoode and Collins (1887) record an 

 "ice bird" (probably a dovekie) taken from one caught on Georges Bank. 



