VI 



For convenience of reference tliese statements liave 

 been develox^ed in the accompanyinii' diagram, rnfortu- 

 nately. no reliable records of the lisheries at the head of 

 the Bay and the mouth of the Susquehanna River for 

 the years prior to 1870, could be i)rocured : and, conse- 

 quently, no such comparative diagram, or statement, of 

 the movement of the fish previous to that time can now 

 be made. Before analyzing the diagram let us glance at 

 the tal)le showing the amount of fisli marli'ef'd in Wash- 

 ington and Alexandi'ia during the last iifteen years ; — 

 the records of sales in these two cities indicating, pretty 

 accurately, the yield from the Potomac River, per- 

 haT)s ten or twenty per cent, of the total amount being 

 taken up by the inhabitants of the adjacent country. 



Assuming, then, that the number of lish sold in the 

 two cities named represents the yield of the Potomac, 

 we have a total catch of 10. 6:21. 444 shad for the Iifteen 

 years from 1866 to 1880: giving an average of 870,109 for 

 the first live years; 874.114 for the next five: and 880.06»5 

 for the period from 1876 to 188o ; and showing a very 

 remarkable decrease in the yield from this river. The 

 Yield for the second live years, that is, from 1871 to 1875, 

 although apparently gTeater than the average of the 

 previous five years, was. no doubt, the result of more 

 extended fishing : as comparatively few fish were taken 

 in 1866. in consequence of the lisheries not lia^ing recov- 

 ered from the effects of the war. and of th^ fishermen 

 being without equipment. It ^^ill be observed that this 

 decrease would be even more marked but for the catches 

 of 1879 and 1880 : as, in the last mentioned year, when 

 the results of artificial pro]3agation began to be realized, 

 we have 555,122 — an increase of more than 200.000 over 

 the average yield. 



The average of the preceding live years, again, was 

 enlarged by the exceptional yield of 1873 : l)ut the large 

 catch of this year was probably owing to the jDrevalence 

 of easterly winds and other meteorological influences; as 



