344 NATURAL HISTORY OP AQUATIC ANIMALS. 



Shoals light-ship. The fish "strike in" to Block Island and Moutauk Point every year about the 

 1st of July. They are first seen twenty to twenty-five miles southeast of Montauk. At the end 

 of August they are most abundant in the South Channel. Captain Ashby never saw them at any 

 time so abundant as August 15, 1859. He was cruising between George's Banks and the South 

 Shoals. It was a calm day, after a fog. He could at any time see twenty-five or thirty from the 

 mast-head. They turn south when snow comes. 



Capt. George H. Martin, of East Gloucester, tells me that the Gloucester vessels employed in 

 this fishery expect to be on the fishing grounds south of George's Banks by the 10th of June. 

 They almost always find the fish there on their arrival, following the schools of mackerel. They 

 "tend on soundings," like the mackerel. The first Sword-fish of 1877 was taken June 10; the 

 first of 1878, June 14. 



The statements already quoted, and numerous conversations with fishermen not here recorded, 

 lead me to believe that Sword-fish are most abundant on the shoals near the shore and on the 

 banks during the months of July and August; that they make their appearance on the frequented 

 cruising grounds between Moutauk Point and the eastern part of George's Banks some time 

 between the 25th of May and the 20th of June, and that they remain until the approach of cold 

 weather in October or early iu November. The dates of the capture of the first fish on the cruis- 

 ing ground referred to are recorded for three years, and are reasonably reliable: 1875, June 20; 

 1877, June 10; 1878, June 14. 



South of the cruising ground the dates of arrival and departure are doubtless farther apart ; 

 north and east the season being shorter. There are no means of obtaining information, since the 

 men engaged in this fishery are the only ones likely to remember the dates when the fish are seen. 



REASONS OF THE COMING OF SWORD-FISH UPON OUR COAST. The Sword-fish comes into 

 our waters iu pursuit of its food. At least this is the most probable explanation of their move- 

 ments, since the duties of reproduction appear to be performed elsewhere. Like the tunny, the 

 blue-fish, the bouito, and the squeteaguc, they pursue and prey upon the schools of menhaden and 

 mackerel which are so abundant in the summer months. "When you see Sword-fish, you may 

 know that mackerel are about," said an old fisherman to me. " Where you see the fin-back whale 

 following food, there you find Sword-fish," said another. The Sword-fish also feeds upon squid, 

 which are at times abundant on our banks. 



TUB INFLUENCE OF TEMPERATURE UPON THE MOVEMENTS OF THE SWORD-FISH. To what 



extent this fish is amenable to the influences of temperature is an unsolved problem. We are 

 met at the outset by the fact that they are frequently taken on trawl-lines which are set at the 

 depth of one hundred fathoms or more, on the off-shore banks. We know that the temperature of 

 the water at those localities and at that depth is sure to be less than 40 Fahrenheit. How is this 

 fact to be reconciled with the known habits of the fish, that it prefers the warmest weather of 

 summer and swims at the surface in water of temperature ranging from 55 to 70, sinking when 

 cool winds blow? The case seemed clear enough until this inconvenient discovery was made, that 

 Sword-fish are taken on bottom trawl-linos. In other respects their habits agree closely with 

 those of the mackerel tribe, all the members of which seem sensitive to slight changes in tempera- 

 ture, and which, as a rule, prefer temperature iu the neighborhood of 50 or more. 



There is one theory by which this difficulty may be avoided. We may suppose that the 

 Sword-fish take the hooks on their way down to the bottom ; that in their struggles they get 

 entangled in the line and hooks, and when exhausted sink to the bottom. This is not improbable. 

 A conversation with some nshermtiu who have caught them in this way develops the fact that the 

 fish are usually much tangled in the Hue, and are nearly lifeless when they are brought to the 



