ARTIFICIAL PROPAGATION OF SHAD 465 



Bay. It has been found in the Potomac River occasionally, in 

 limited numbers, in August and September, and even during the last 

 week in December. Its movements are apparently largely controlled 

 by the water temperature. It is believed that it seeks to occupy an 

 area having a temperature of 60° or 70°, and that its migrations are 

 determined by the shifting of this area. 



SHAD IN THE RIVERS 



The annual migration of the shad from the ocean to the rivers is 

 for the sole purpose of reproduction. It ascends to suitable spawning 

 grounds, which are invariably in fresh water, occupying several weeks 

 m depositing and fertilizing its eggs in any given stream. 



Its mirations from the sea are in quite a regular succession of 

 time with relation to latitude. It first appears in the St. Johns 

 River (Fla.) about November 15, the season of greatest abundance 

 being February and March. In the Savannah River (Ga.) and the 

 Edisto (S. C.) the run begins early in January and ends the last of 

 March. In the North Carolina rivers these stages of the migration 

 are a little later. In the Potomac River advance individuals appear 

 late in February, but the fish is most numerous in April. In the 

 Delaware River the maximum run occurs about May 1. It reaches 

 the Hudson River the last of March, and is found in the Connecticut 

 toward the end of April, is most abundant the last of May, and leaves 

 the stream late in July. In the Kennebec and iVndroscoggin Rivers 

 (Me.) it is first taken in April and has left by the middle of July. In 

 the St. John River (New Brunswick) it appears about the middle of 

 May, and in the Miramichi River (New Brunswick) late in May. 



The main body of shad ascends the rivers when the temperature of 

 the water is from 56° to 66°, the numbers diminishing when the tem- 

 perature is over 66°. The movement of the shad up the rivers is not 

 constant, but in waves, causing a rise and fall in the catch. Succes- 

 sive schools enter the Potomac from February to July, the males pre- 

 ceding the females. Of 61,000 shad comprising the first of the run 

 received at Washington, D. C, from March 19 to 24, 1897, 90 per 

 cent were males. Toward the close of the season males are extremely 

 scarce. 



The erection of impassable dams along the rivers and streams was 

 probably the first thing to curtail the natural spawning grounds of 

 these fish and to seriously check their natural increase. 



As shad enter the rivers only for the purpose of spawning, the 

 fisheries are necessarily prosecuted during the spawning season and 

 often upon the favorite spawning grounds. The increase of population 

 has created a larger demand for these fish, and an increased intensity in 

 the fishing has resulted. The number of shad that reach fresh water 

 has therefore been greatly curtailed by assiduous fishing with aU 

 kinds of contrivances in the estuaries and in the mouths and lower 

 parts of rivers. 



From spa^^^ling until their return to the rivers shad eggs and fry 

 are preyed upon oy other fish, so that the majority of the young do 

 not survive their few months' sojourn in fresh water, and of those 

 that leave the rivers each season a very small percentage reaches 

 maturity to deposit its eggs and contribute to the perpetuation of the 

 40113°— 25 2 



