FISHES OF THE GULF OF MAINE 225 



Food. — The swordfish is a fish eater. During its stay in American waters it 

 feeds on mackerel, menhaden, bluefish, silver hake, butterfish, herring, and indeed on 

 any of the smaller schooling fishes, buckets of which have been taken from swordfish 

 stomachs. Squid, too, are often found in them and may be their chief diet at times. 

 One that we killed on Georges Bank on July 24, 1916, was full of silver hake, and 

 another harpooned off Halifax contained a squid {Ommostrephes) and fragments 

 of silver hake. They have often been described as rising through schools oi mackerel, 

 menhaden, etc., striking right and left with their swords, and then turning to gobble 

 the dead or mangled fish. Judging from the commotion, we have seen them so 

 employed on more than one occasion, though never close enough to actually follow 

 the event. According to swordfishermen, it is not unusual for swordfish to contain 

 black deep-sea fishes, and Kingsley '* records two stomiatids (Echiostoma harlatum 

 Lowe) taken from the stomach of one harpooned over the offshore slope of Georges 

 Bank, so fresh that the phosphorescent organs were still in good condition, and since 

 these black fish probably alwaj's keep below 150 fathoms this is sufficient evidence 

 that swordfish sometimes forage at considerable depths. It seems that they some- 

 times endeavor to strip line trawls set for hahbut and tilefish of the smaller fish 

 already caught, for they are occasionally brought up entangled in the line, but never 

 actually hooked. 



Habits. — Swordfish are supposed to spawn in spring and early sunmaer, but 

 judging from the state of the ovaries and spermaries this can not apply to the Ameri- 

 can fish, which must spawn during the part of the year when absent from our coasts, 

 and probably in the warmer parts of the Atlantic basin, for Liitken '° tound sword- 

 fish fry as small as 10 mm. — evidently hatched but a short time previous — between 

 the latitudes of 20° and 39° N. The fact that they are thin when they return to us 

 in spring, but fatten during the summer stay, is further evidence that the}'^ are spent 

 before they appear off the coast. 



Nothing is definitely known of the rate of growth of the swordfish. It has 

 been supposed that the young fish of half a pound to 12 pounds taken in winter in 

 the Mediterranean are the product of the past spring's spawning, but this would 

 call for unusually rapid growth. The very large size attained may equally be the 

 result of long life. 



Although swordfish congregate temporarily in certain localities they do not 

 school, but are always seen scattered about either singly or at most two fish swim- 

 ming together. On this point the earlier published accoimts, statements by fisher- 

 men, and our own rather limited experience are in accord. On calm days swordfish 

 often lie quiet on the sm-face or loaf along with both the high dorsal and the tip 

 of the caudal fin above water, and it is while so employed that they are harpooned. 

 When at the surface swordfish do a good deal of jumping, perhaps in a vain attempt 

 to shake off the remoras that so often cling to them. On July 28, 1914, off Shelburne, 

 one leaped clear of the water four or five times in rapid succession close to the 

 Grampus. 



" Science, new series, Vol. LVI, 1922, pp. 225-226. New York. 

 '• Spolia Atlantica, 1S80-1892. Kjfjbenhavn. 



