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FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



even sea birds have been found in them. 34 Fish- 

 ermen have reported finding in halibut the heads 

 and backbones of cod thrown overboard, and a 

 variety of indigestible objects such as pieces of 

 wood or iron, and even fragments of drift ice. 



The diet of the halibut in any particular locality 

 depends chiefly on what other ground fish are 

 most easily available. Thus they are reported 

 as feeding chiefly on flatfish on Georges Bank, 

 but on cod, haddock, cusk, and sculpins on other 

 groimds. 



Halibut, like other flounders, must be nearly 

 invisible as they lie on bottom, capturing any 

 fish that passes within reach by a sudden rush. 

 On one occasion a halibut of about 70 pounds was 

 seen at the surface trying to kill a small cod with 

 blows of its tail. "We hove out a dory and two 

 men went in her taking with them a pair of gaff 

 hooks. They soon returned bringing not only the 

 halibut but the cod." 36 And halibut are very 

 destructive to smaller fish. We read, indeed, of 

 half a bushel of flatfish taken from one halibut. 

 And fishermen said the appearance of a school of 

 halibut soon drove away the cod and haddock, 

 in the days when halibut were still plentiful on the 

 shoaler banks. 



It appears that halibut do not eat many 

 invertebrates at least in the Gulf of Maine, or in 

 Nova Scotian waters. But a case is on record 

 when 6 lobsters, 6 inches long, were found in the 

 stomach of one. And Jensen found that halibut 

 caught in deep water off west Greenland had fed 

 chiefly on large shrimps (Pandalus borealis) . 3C 



According to fishermen who have watched them 

 in clear shallow water, "The halibut will advance 

 to the bait . . . then retreat 4 or 5 feet from it 

 . . . after repeating this performance several 

 times — generally three or four — the fish seems to 

 make up its mind to eat the bait, and, suddenly 

 darting toward it, swallows it down at a gulp." 37 



Halibut, in their own turn, fall prey to seals, and 

 especially to the Greenland shark, for which they 

 are a staple article of diet. 



» Smitt (Scandinavian Fishes, vol. 1, 1892, p. 414) speaks of a halibut 

 that had eaten a razor-billed auk; Good and Collins (Fish. Ind. U. S., Sect. 5, 

 vol. 1, 1887, p. 35) record an "lee bird" (probably a dovekie) as taken from a 

 halibut caught on Georges Bank; and Scudder (Fish. Ind. U. S., Sect. 5, 

 vol. 1, 1887, p. 110) reports finding the skeleton of a gull in the stomach of 

 another. 



»» Ooode, Fish. Ind. U. S., Sect. 1, 1884. p. 196. 



>' Meddelelser, Dansk. Komm. Havundcrs., Scr. Fisk., vol. 7, No. 7, 

 1925, p. 18. 



» G oode and Collins, Fish. Ind. U. S., Sec. 5, vol. 1, 1887, p.. 17. 



Large halibut are very prolific, the ovaries of an 

 Atlantic female of about 200 pounds having been 

 estimated as containing 2,182,773 eggs, while a 

 female of the Pacific form of "140 pounds may 

 have as many as 2,700,000." 38 



Very little is known about the breeding of the 

 Atlantic halibut. In the eastern Atlantic halibut 

 spawn chiefly in March, April, and May with the 

 chief production of eggs in April, while a few fe- 

 males may ripen as early as the end of January, 

 and some not until June. 39 Off west Greenland 

 they spawn late in spring. 40 Off the American 

 coast it seems that the spawning season continues 

 through the summer, for fishermen have reported 

 ripe fish, both male and female, in April, May, 

 June, July, August, and early September at var- 

 ious localities from Georges Bank to the Grand 

 Banks; 41 while the report that part of the eggs in 

 the ovaries of a fish examined on Banquereau by 

 representatives of the Bureau of Fisheries on Sep- 

 tember 13, 1878, were ripe, but others immature, 

 is evidence (if correct) that individual halibut may 

 spawn over a considerable period. 



Presumably they spawn on bottom, like other 

 flat-fishes, but definite information is lacking. 

 The Pacific halibut is known to spawn at depths 

 of 150 fathoms to about 225 fathoms: 42 and 

 European students, generally, have believed that 

 the Atlantic fish spawns deeper still, perhaps even 

 outside the 400-500 fathom line; evidence is that 

 naturally spawned eggs have been taken only 

 where the depth was greater than about 550 

 fathoms (1000 meters), the drifting larvae less 

 than 19 mm. long only over depths greater than 

 about 220 fathoms (400 meters). 43 On the other 

 hand, halibut spawn regularly in the aquarium at 

 Trondhjem, Norway, where the eggs have been 

 fertilized artificially and hatched successfully. 44 

 This, with fishermen reports of ripe fish, both fe- 

 males and males, on the slopes of all the offshore 

 Banks east of Cape Cod and, with Cox's report of 



> ! Clemens and Wilby, Bull. No. 68, Fisheries Res. Board Canada, 1946, 

 p. 312. 



" For a general survey of available information, see Taning, Meddelelser 

 Komm. Danmarks Fisk. Havunders., Ser. Fisk., vol. 10, No. 4, 1939, p. 14. 



" A larva 14.75 mm. long taken on June 19 and another 21 mm. long taken 

 on July 7 is recorded by Jensen (Rapp. Proc. Verb. Cons. Intern. Explor. 

 Mer, vol. 39, p. 96, 1926). 



<> Goode (Fish and Fishery Industr. U. S., Sec. 1, 1884, pp. 196-197), 

 mentions reports to this effect. 



<2 Clemens and Wilby, Bull. 68, Fish. Res. Bd. Canada, 1946, p. 312. 



« Tantng, Meddel. Komm. Danmarks Fisk. Havunders., Ser. Flskeri, 

 vol. 10, No. 4, 1936, p. 8. 



" Rollefsen, Kgl. Norske Vidensk. Selsk. Trondhjem, Forhand., vol. 7, 

 No. 7, 1934. 



