RELATIONS OF THE SWORD-FISH TO TEMPERATURE. 345 



surface. A confirmation is found in the observations of Captain Baker, of the schooner " Peter 

 D. Smith," of Gloucester, who tells me that they often arc taken on the hand-lines of the cod-fisher- 

 nien on George's Banks. His observations lead him to believe that they only take the hook when 

 the tide is running very swiftly and the lines are trailing out in the tideway at a considerable 

 distance from the bottom, and that the Sword-fish strike for the bottom as soon as they are 

 hooked. This theory is not improbable, as I have already remarked, but I do not at present 

 advocate it very strongly. I want more facts before making up my own mind. At present the 

 relation of the Sword-fish to temperature must be left without being understood. 



The appearance of the fish at the surface depends apparently upon temperature. They are 

 seen only upon quiet summer days, in the morning before ten or eleven o'clock, and in the after- 

 noon about four o'clock. Old fishermen say that they rise when the mackerel rise, and when the 

 mackerel go down they go down also. 



PROBABLE WINTER HABITAT OF THE SWORD-PISH. Regarding the winter abode of the 

 Sword-fish conjecture is useless. I have already discussed this question at length with reference 

 to the menhaden and mackerel. With the Sword-fish the conditions are very different. The 

 former are known to spawn in our waters, and the schools of young ones follow the old ones in 

 toward the shores. The latter do not spawn in our waters. We cannot well believe that they 

 hibernate, nor is the hypothesis of a sojourn in the middle strata of mid-ocean exactly tenable. 

 Perhaps they migrate to some distant region, where they spawn. But then the spawning time of 

 this species in the Mediterranean, as is related in a subsequent paragraph, appears to occur in 

 the summer mouths, at the very time when Sword-fish are most abundant in our own waters, 

 apparently feeling no responsibility for the perpetuation of their species. 



MOVEMENTS OP INDIVIDUAL SWORD-PISHES. A Sword-fish when swimming near the surface 

 usually allows its dorsal fin and the upper lobe of its caudal fin to be visible, projecting out of the 

 water several inches. It is this habit which enables the fisherman to detect the presence of the 

 fish. It swims slowly along, and the fishing schooner with a light breeze finds no difficulty in 

 overtaking it. When excited its motions are very rapid and nervous. Sword-fish are sometimes 

 seen to leap entirely out of the water. Early writers attributed this habit to the tormenting pres- 

 ence of parasites, but this theory seems hardly necessary, knowing what we do of its violent 

 exertions at other times. The pointed head, the fins of the back and abdomen snugly fitting into 

 grooves, the absence of ventrals, the long, lithe, muscular body, sloping slowly to the tail, fit it 

 for the most rapid and forcible movement through the water. Prof. Richard Owen, testifying in 

 an English court in regard to its power, said : 



" It strikes with the accumulated force of fifteen doable-handed hammers. Its velocity is 

 equal to that of a swivel-shot, and is as dangerous in its effects as a heavy artillery projectile." 



n 



Many very curious instances are on record of the encounters of this tisli with other fishes, or 

 of their attacks upon ships. What can be the inducement for it to attack objects so much larger 

 than itself it is hard to surmise. Many are familiar with the couplet from Oppian: 



Nature her bounty to his mouth ronliiifid, 

 Gavi; him a swonl, lint Irft uiuirnn'il his mind. 



It surely seems as if a temporary insanity sometimes takes possession of the fish. It is not 

 strange that, when harpooned, it should retaliate by attacking its assailant. An old sword-fish 

 fisherman told Mr. Blackford that his vessel had been struck twenty times. There are, however, 

 many instances of entirely unprovoked assault on vessels at sea. Many of these are recounted in 

 a later portion of this memoir. Their movements when feeding are discussed below, as well as 

 their alleged peculiarities of movement during the breeding season. 



