weather. Under favorable conditions, most of 

 the streams have excellent capacities for sup- 

 porting and producing trout. Brook trout up to 

 14 inches long and rainbow trout over 20 inches 

 long are reported by anglers . On the wet side of 

 the weather cycle, park personnel can expect 

 complaints from fishermen that the streams are 

 becoming over -populated with small, large - 

 headed trout. It must be remembered then that 

 the abundance is temporary, and the populations 

 will be reduced again by the droughts and flash 

 floods which occur during the dry years of the 

 veather cycle. Significant fluctuations in popu- 

 lations will occur also in some streams as a 

 result of short droughts or local floods. Thus, 

 dependent upon the weather, the sport fishery of 

 the park is marginal. 



Demands will be made to stock hatchery- 

 reared trout during periods when the wild popula- 

 tions are small. It was apparent, however, in 

 the present study that the drought and flood 

 conditions which decimated the wild fish would 

 be equally or more inimical to stocked trout . 

 It was apparent also that small numbers of 

 survivors can quickly repopulate the streams as 

 soon as water conditions permit. 



SUMMARY 



The populations of native brook trout in 

 streams of Shenandoah National Park increased 

 from relative scarcity in the late 1930's to 

 abundance in 1950. The National Park Service 

 requested a survey by the Fish and Wildlife 

 Service to answer, in part, the complaints of 

 fishermen that there were too many small, 

 large -headed trout. 



The fishery situation in the park changed 

 radically at the time the survey was undertaken. 

 A series of severe droughts, beginning in 1951 

 and continuing into 1955, curtailed reproduction 

 and caused large losses of trout and other 

 species. Up to 75 percent of the lengths of 

 some streams were dry in the summer of 1954. 

 The drying stream beds, the high temperatures 

 of water in isolated pools, and predation by 

 water snakes contributed to the heavy mortality. 



Two unusually severe flash floods in 

 1954 damaged stream beds and caused further 



losses of fish. The floods appeared to be 

 especially damaging when they occurred as 

 interruptions in a drought. 



The park was closed to fishing in 1954 

 and 1955 to protect the small remnants of the 

 trout populations . 



There was no evidence that any species 

 had been eliminated during the drought years . 



Recovery of the fish populations was 

 rapid despite the small numbers of adult fish, 

 once water conditions improved enough to 

 permit reproduction and good survival. One of 

 the better streams which was surveyed annually 

 contained 8.5 pounds of brook trout per acre 

 in 1954, 34.5 pounds in 1955, and 43.3 pounds 

 in 1956. Within the two years, the trout and 

 other species also distributed themselves 

 throughout long sections of mainstreams and 

 headwaters which were dry in 1954. Among 

 the non-game species, fantail darters made a 

 particularly quick recovery in numbers and 

 distribution. 



An attempt to augment the recovery of 

 brook trout by stocking Appalachian -strain 

 fingerlings in 1955 appeared unsuccessful. 



The growth of trout was relatively rapid 

 during the period of population recovery. Two- 

 year -old trout in one of the principal streams 

 in 1950 ranged from 4 to 8 inches long; fish of 

 the same age in 1956 and 1957 ranged from 6 

 to 11 inches. Age III fish in 1950 were 5 to 10 

 inches long, but those of the same age in 1956 

 and 1957 were 8 to 13 inches. 



The park was reopened to fishing in 1956. 

 The season and subsequent seasons were set to 

 conform more closely with those of the State of 

 Virginia. Legal-size trout (9 inches) are crop- 

 ped closely, but populations have remained 

 good as a result of favorable water conditions. 

 Two streams were placed under fishing-for-fun- 

 only regulations in 1961. 



The welfare of trout populations in the 

 park is dependent to an unusual extent on the 

 weather cycle. The numbers of trout will vary 

 from abundant in wet years to scarce in drought 



14 



