SHAD FISHERIES OF THE ATLANTIC COAST. 113 



ascending above that point, and as they strayed about in tlie river 

 below the obstruction they were taken in greater abundance than 

 lornierly. At the Parsonage tisliery, near the mouth of the river and 

 40 miles below the dam, the shad yield during the twenty years pre- 

 ceding the erection of the obstruction averaged 9,854 annually; during 

 the live years following 1849 the annual catch averaged 19,490; during 

 the next ten years it was but 8,304, and for the following six years, 

 1805-1870, the annual average was but 4,48l* shad, less than one-half 

 the former yield. The record of the catch on the Connecticut from 

 1853 to 1890 shows that the total yield below the dam decreased from 

 nearly 500,000 annually to an average of less than one- tenth of that 

 number. In a few rivers the development of water-power has resulted 

 in completely exterminating the anadromous fishes, this being the case 

 in the Thames, the Blackstoue, the Merrimac, the Saco, and other 

 rivers. However, instead of the employment of a few hundred persons 

 in taking fish each spring, the water-power on those streams affords 

 employment to thousands of mill operatives. 



The utility of the spawning areas below the dams has also been 

 impaired by chemicals, sawdust, and other refuse from mills and towns 

 on the river banks. In a number of small streams these have almost 

 completely destroyed the spawning and breeding areas, but regulations 

 against this practice now exist in many States. 



Another factor having some effect on limiting the range of shad up 

 the rivers is the increased agricultural operations. At the time of the 

 settlement of the river valleys most of those areas were covered with 

 forests, and the ground was carpeted with leaves and moss, which 

 checked the surface liow of water and restricted its evaporation, thus 

 tending to constancy in the flow of rivers, and freshets were rare and 

 of insignificant proportions. With increase of population the forests 

 were cleared away and large areas of land brought under cultivation, 

 causing injurious meteorological changes and more numerous and 

 destructive floods. During heavy rains the plowed soil upon the hillsides 

 is easily washed into gullies through which the cold water is quickly 

 conveyed to the rivers, filling them beyond their capacity and bringing 

 into them masses of earth and other debris, thus covering the spawning- 

 grounds. The freshets are soon over, and the flow of water in the 

 streams becomes so small that shad are not induced to proceed so far 

 up as formerly. 



On some of the Southern streams decreased navigation has resulted 

 in reducing the length of shad range. This is especially true of the 

 Combahee, the Ashepoo, the Edisto, the Chickahominy, the Matta- 

 poni, and the Pamunkey, the channels of which are now encumbered 

 with drifting logs, overhanging trees, brushwood, and shoals of loose, 

 shifting sand, through which a passageway for the ascent of fish was 

 formerly maintained by navigation and the rafting of timber. 



The most important factor in reducing the inland range is the exten- 

 sive fisheries near the coast. In the first half of the present century 

 F. R. 98 8 



