286 MIGRATION OF ANIMALS. 



The parents, however, after this important office has been 

 performed, hasten back to the sea. Toward the end of March, 

 the young fry begin to appear, and they gradually increase in 

 size till they acquire the length of four or five inches. About 

 the beginning of May, all the considerable rivers of Scotland 

 are full of salmon fry. After this period, they migrate to the 

 sea. About the middle of June, the earliest of the fry begin 

 to appear again in the rivers. At that time they are from 

 twelve to sixteen inches long, and gradually augment, both in 

 number and size, till about the end of July or the beginning 

 of August, when they weigh from six to n'md pounds. This 

 is a very rapid growth. But a gentleman of credit at War- 

 rington informed Mr. Pennant of a growth still more rapid. 

 A salmon, weighing seven pounds and three quarters, was 

 taken on the 7th day of February. It was marked on the 

 back, fin, and tail, with scissors, and then turned into the 

 river. It was retaken on the 17th day of the following month 

 of March, and then it weighed seventeen pounds and a half. 

 The season for fishing salmon in the Tweed begins on the 

 30th of November, and ends on old Michaelmas day. In that 

 single river, it is computed that no less than two hundred and 

 eight thousand, at a medium, are annually caught, which, to- 

 gether with the products of many other rivers on both sides of 

 Scotland, not only afford a wholesome and palatable food to 

 the inhabitants, but form no inconsiderable article of commerce. 

 Herrings are likewise actuated by the migrating principle. 

 These fishes are chiefly confined to the northern and temper- 

 ate regions of the globe. They frequent the highest latitudes, 

 and are sometimes found on the northern coast of France 

 They appear in vast shoals on the coast of America, as far 

 south as Carolina. In Chesapeake Bay there is an annual 

 inundation of herrings; and Mr. Catesby informs us, that they 

 cover the shores in such amazing numbers as to become offen- 

 sive to the inhabitants. The great winter rendezvous of the 

 nerrings is within, or near, the Arctic Circle, where they re- 

 main several months, and acquire strength after being weak- 

 ened by the fatigues of spawning, and of a long migration. 

 In these seay, food is much more abundant than in warmer 

 latitudes. . They begin their migration southward in the 

 spring, and appear off the Shetland Islands in the months of 

 April and May. These, however, are only the forerunners of 

 the immense shoal which arrives in June. Their approach 

 is recognized by particular signs, such as the appearance of 

 certain fishes, the vast number of birds, as gannets or solan 





