considered it as fair trout water; Henderson 

 found trout up to 12 inches long plentiful in 1950; 

 and Chamberlain called the bottom fauna rich. 

 We observed numerous trout up to 14 inches long 

 in 1952. 



A few of the large streams, such as the 

 Rapidan, Hazel, Hughes, and Staunton rivers, 

 were Listed as good trout waters by King or 

 Taylor and as excellent by Henderson or park 

 rangers about 10 years later. On the other hand, 

 several streams remained relatively poor for 

 trout through the years . 



The improvements in the trout popula- 

 tions were the result, in large degree, of the 

 continuous and various efforts of the National 

 Park Service. Before 1950, the larger and more 

 accessible streams were stocked annually with 

 fingerling and legal size brook trout. The North 

 Fork of Moorman River was also stocked with 

 rainbow trout. Fishing seasons were only slight- 

 ly more than 2 months long; a 7-inch minimum 

 size restriction was imposed; and the use of 

 natural bait was prohibited. Furthermore, the 

 streams were well protected, and the erosion of 

 roads and hillsides into the streams was reduced. 



These efforts, in addition to favorable 

 weather and water conditions, contributed to 

 an overabundance of small trout by 1950-1951. 

 Henderson reported that many of the trout were 

 only 2 or 3 inches long at the end of their second 

 summer, and that many sexually mature fish 

 were only 4 or 5 inches long. Fishermen com- 

 plained to park rangers about the abundance of 

 large-headed, sublegal trout. This situation was 

 a large part of the reason that the National Park 

 Service requested the Fish and Wildlife Service 

 to perform a survey of the fishery . Before the 

 survey could be started, however, the trout 

 population began to decline. 



DECLINE OF TROUT POPULATIONS 



Ehrougftt 



A series of severe droughts began in 

 Shenandoah in the autumn of 1951 and continued 

 into 1955. They were related to the widespread 

 drought conditions which affected central and 

 southwest States from 1952 to 1955 (Larimore, 



Childers, and Heckrotte, 1959). The dry periods 

 in the park in 1951 and 1952 occurred during the 

 fall months. In 1953, the drought persisted from 

 August until late fall, whereas in 1954 it lasted 

 from June to October. Less damaging conditions 

 occurred during the summer and fall of 1955, 

 The record of rainfall for the July -October period 

 each year from 1945 through 1959 illustrates the 

 succession of drougjits (table 2). 



Water levels:-- Stream flows were quick- 

 ly and strikingly affected by the droughts . Many 

 riffle areas, especially in the headwaters, were 

 dry during the autumns of 1951 and 1952. The 

 longer drought in 1953 caused most of the streams 

 to become largely dry between their sources and 

 the park boundary . Shrunken pools were widely 

 isolated. Temperature and pH readings in adjacent 

 but isolated pools disclosed that the flow of ground 

 water between them was small. The temperatures 

 differed up to 3° F. between pools and pH ranged 

 from 6.0 to 7.0. 



Increases in acidity were greatest in tiie 

 fall and they were believed to be due to heavy 

 accumulations of fallen leaves in the water. 

 Kendall and Dence (1927) reported a similar sit- 

 uation which adversely affected trout of certain 

 New York streams. The concentrations of dis- 

 solved oxygen and carbon dioxide remained with- 

 in favorable limits for fish, however, because 

 the low temperatures prevented rapid decompo- 

 sition of the leaves. 



The most critical effects of drought on 

 water levels were observed in 1954. Beginning 

 in June, stream flows decreased rapidly. The 

 conditions on Big Run were considered typical of 

 those on many of the streams . The normal flow 

 of 5,400 gallons per minute at a station located 

 midway between the source of the stream and the 

 park boundary was reduced in July to 14 gallons 

 per minute and in August to 10 gallons per minute. 

 It was estimated that 75 percent of the length of 

 the stream was dry by late August. In fact, the 

 entire headwater section which previously con- 

 tained numerous trout was completely dry. 



The majority of the streams during the 

 summer flowed at less than 0.2 cfs. The larger 

 Rapidan River and Hughes River had only 5.5 and 

 2.0 cfs respectively in mid-August, representing 

 only small fractions of normal flows . 



