395

THE TROUT FISHERY

IN SHENANDOAH NATIONAL PARK

SPECIAL SCIENTIFIC REPORT-FISHERIES Na 395

UNITED STATES BEPARTMENT^OFJTHE^JNTERIOR^
FISH AND WILDLiTe SERVICE

EXPLANATORY NOTE

The series embodies results of investigations, usually of restricted
scope, intended to aid or direct management or utilization practices and as
guides for administrative or legislative action. It is issued in limited quantities
for official use of Federal, State or cooperating agencies and in processed form
for economy and to avoid delay in publication .

United States Department of the Interior, Stewart L. Udall, Secretary

Fish and Wildlife Service, Clarence F. Pautzke, Commissioner

Bureau of Sport Fisheries and Wildlife, Daniel H. Janzen, Director

THE TROUT FISHERY IN
SHENANDOAH NATIONAL PARK

By

Robert E. Lennon

Special Scientific Report- -Fisheries No. 395

Washington, D. C ,
November 1961

CONTENTS

Page

Introduction 1

The streams 1

Collection of data 2

The status of trout populations prior to 1952 2

Decline of trout populations 4

Drought 4

Water levels 4

Water temperatures 6

Predation 6

Trout spawning 7

Floods 7

Scouring 7

IDamage to aquatic life 7

Population estimates 7

The recovery of trout populations 8

Stocking 8

Population estimates 8

1955 8

1956 10

1957 10

1958 12

1959 12

Growth of trout 12

The sport fishery 13

Season and regulations 13

Creel census 13

Management aspects 13

Summary 14

Acknowledgements 15

Literature cited 15

THE TROUT FISHERY IN
SHENANDOAH NATIONAL PARK

By

Robert E. Lennon
Bureau of Sport Fisheries and Wildlife
Fish Control Laboratory
La Crosse, Wisconsin

ABSTRACT

Populations of brook trout in streams of Shenandoah National
Park were reduced drastically early in the past decade by a succession
of unusually severe droughts and floods. The drying of stream beds,
predation, and scouring were principal factors in the loss of fish. The
park was closed to fishing in 1954 and 1955 to protect survivors.

The small numbers of survivors quickly repopulated the streams
after drought conditions abated. The stocking of hatchery -reared
fingerling trout in selected waters failed to augment the recovery of
populations. Survival and growth of young, wild trout were especially
good. Their redistribution through miles of previously dry streams
was rapid. The park was opened again to fishing in 1956 under regula-
tions which restrict the take but afford an increase in sporting opportunity.
Two streams were placed under fishing-for -fun -only regulations in 1961.

The welfare of the trout populations is dependent mostly on the
weather cycle. Fish may be abundant in wet years but very scarce in
dry ones. Thus, the stream must be managed as marginal for trout.

The brook trout (Salvelinus fontinalis, Wildlife Service to conduct a long-term study

Mitchill) is the principal sport fish in Shenandoah which began in 1952 and continued through 1959.

National Park. Its numbers may fluctuate dras- It was opportune in that it included one of the

tically, however, due to factors other than more critical periods with respect to the fishery

fishing regulations and fishing pressures. With- since the establishment of the park in 1930.
in the past decade the fish has ranged from

abundant to very scarce and back to abundant THE STREAMS

again.

The park is located within the State of

The National Park Service has endeavored Virginia and lies along the crest and slopes of
on several occasions to evaluate the trout popula- the Blue Ridge Mountains between Front Royal
tions and to define the factors which so strongly on the north and Rockfish Gap on the south. It is
affect them. Brief studies were made on the fish approximately 80 miles long and 1 to 13 miles
and the streams by King (1936), Taylor (1941), wide. The steep ridges and peaks rise 1,000 to
Chamberlain (1951), and Henderson (1950)*. The 3,000 feet above the Piedmont Plateau to the east
results were conflicting, due to reasons which and the Shenandoah Valley to the west. The high-
are explained later in this report. Continuing est peak in the park is 4,049 feet above sea level,
problems in the sport fishery indicated the need

for a comprehensive investigation. Accordingly, The 46 trout streams are short, steep,

the National Park Service requested the Fish and and small to medium in size. Their fishable

*

Typewritten reports to the National Park
Service.

lengths range from 0.5 to 7 miles (average: 2.4
miles) and total 108.5 miles. The streams on
the east slopes drain into the Rappahannock and
James rivers. Those on the west slopes drain
into the Shenandoah River. In general, they
cease to be trout streams within a short distance
from the park.

The sandstone and shale stream beds
scour badly. The waters are clear, colorless,
and very soft. Tests I made at various times
have ranged as follow: 6.0 to 7.0 in pH; 22,000
to 58,000 ohms in resistivity at 77° F.; 19 to 40
ppm in total dissolved solids; and 0 to 10 ppm in
methyl orange alkalinity.

Twenty-one species of fish occur in the
streams, but the distribution of some is limited
(table 1 ). All but the rainbow trout are native to
the park.

Some of the waters were stocked with
hatchery-reared brook trout or rainbow trout up
to 1950, and with brook trout again in 1955. No
stocking has been done since that time.

It is certain that the scenic streams and
their wild trout populations will increase in im-
portance in years to come. First of all, they
are situated within 100 miles of Washington, D.C,
and other large metropolitan areas. Many at-
tractive trails provide access for fishermen and
hikers. Secondly, the condition of the water-
sheds has improved greatly since the park was
established. Most of the poor, mountain-side
farms and cutover areas which contributed to
silting, pollution, and warming of the streams
have reverted to forest. Thus, the potential for
a greater fishery resource is improving.

COLLECTION OF DATA

The research plan included a survey of
each of the 46 streams . Because of limitations
on the time and manpower which could be de-
voted to this park, the surveys had to be accom-
plished over a period of several years . The
plan also called for intensive observations on 6
of the larger or more important streams, and
quantitative data on their fish were collected
each autumn from 1954 through 1957. Supple-
mentary surveys were made on the same waters

during other seasons of the year from 1953
through 1959.

A large amount of rather diffuse data was
obtained in the surveys. Most of the findings
were furnished to the National Park Service in
periodic and annual reports . Only selected data
are presented in this paper to illustrate important
features of the streams and the fish populations .

Trout and other fishes were collected in
measured areas of streams with cresol compound
(Wilkins, 1955), or with electrofishing gear
(Petty, 1955; Lennon and Parker, 1957 and 1958).
A 230 -volt, AC, alternate -polarity electrode
system, used in conjunction with blocks of cattle
salt, was the means employed most success-
fully to obtain reliable estimates of the numbers
and pounds of trout per acre of stream . These
were the first enumerations of the fish popula-
tions in the park because efficient collecting
tools were not available to the previous investiga-
tors.

THE STATUS OF TROUT POPULATIONS
PRIOR TO 1952

We assume that the brook trout were close
to maximum abundance in 1950 and 1951. A re-
, view of the surveys by King (1936), Taylor (1941),
Chamberlain (1951), Henderson (1950), and the
reports by park rangers in 1951 and 1952 show
the development of the trout fishery.

Many of the streams had been abused
prior to the establishment of the park. King be-
gan his observations on them a few years after
they came under park protection, and during a
period of drought as well. He wrote, for example,
that Madison Run was not a trout stream, but 5
years later Taylor rated it as good. Chamberlain
classed it as exceptionally rich in trout food or-
ganisms, and park rangers considered it good
trout water in 1950. We observed a fine spawn-
ing population in 1952.

Brokenback Run was rated as a possible
trout stream by King, as fair by Taylor, but it
became one of the seven most heavily fished
streams by 1950. Big Run, a large and important
stream, appeared to King to be better suited to
smallmouth bass than brook trout. Taylor

Table 1:- The fishes of Shenar

idoah National Park.

Family and species

Distribution

Abimdance

SALMONIDAE

1. Rainbow trout

limited

rare

2. Brook trout

wide

abundant

CYPRINIDAE

3. Eastern redbelly dace

It

It

k. Rosy dace

It

common

5. River chub

limited

rare

6. Common shiner

tt

11

7- Blacknose dace

wide

abiindant

8. Longnose dace

ti

It

9. Creek chub

limited

rare

CATOSTOMIDAE

10. White sucker

11. Northern hog sucker

12. Golden redhorse

13. Torrent sucker

ICTALURIDAE

Ik. Margined madtom

ANGUILLIDAE

15. American eel
CENTRARCHinAE

16. Rock bass

17. Redbreast sunfish

18. Smallmouth bass

wide

II

common

limited

rare

It

abxmdant

rare

PERCIDAE

19. Fantail darter

20. Johnny darter

coin DAE

21. Mottled sculpin

wide

abundant

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 .

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There is no question that large numbers
of fish perished in the drying pools and riffles
because escape was impossible. We had occa-
sion to sample brook trout and other species in
isolated pools which suddenly dried within a day
or two later. As the levels of the pools receded
and the amount of cover was reduced, the larger
trout attempted to move downstream. Their at-
tempts to cross drying or dry riffle areas were
observed in several instances. Between periods
of rest, the trapped fish charged the downstream
edge of their isolated pool seeking an avenue of
escape. The attempts were more than probes
since the fish often threw themselves out of the
water temporarily. It may be significant that
the larger trout, 10 or more inches long, were
quick to disappear from the streams when sec-
tions began to dry up .

Water temperatures:-- The droughts in
the autumns of 1951, 1952, and 1953 were not
complicated by unfavorable water temperatures.
During the summer drought in 1954, however,
temperatures as high as 82° F. were measured
in the isolated pools . The high temperatures
persisted for days at a time, and the trout were
in distress . Adult trout rested upright on the
stream bottom, and made no attempt to support
themselves on pectoral fins. They showed no
movement except a rapid rate of respiration.
Counts of 136 gill movements per minute were
made on 10 -inch trout lying in 76° water. Em-
body (1921) observed that brook trout in stream
water at 83.3° exhibited great distress and a
refusal to eat, but survived.

The trout also showed no fear. One
could wade into the pools and touch them . No
mortalities, however, could be charged directly
to the high temperatures . Rather, the warm
water may have contributed to an increase of
losses by predation.

Predation:-- The drying of the streams
caused the fish to congregate in isolated pools .
As the levels of these pools receded, much of
the usual cover became unavailable, and the
fish were exposed to easy predation. Further-
more, the high temperatures of water in July
and August 1954 made the trout almost helpless
and subject to easy capture. During autumn, ac-
cumulations of fallen leaves served as temporary
cover and the fish hid in them .

Common watersnakes (Natrix sipedon)
killed many trout. This species is abundant in
the park, and in fact, many local fishermen shun
the streams in summer because of their dislike
for the numerous "moccasins" . As many as five
large watersnakes were observed prowling at
once in one shrunken pool. Three individuals
were killing trout simultaneously in another small
pool. One of the snakes, 31.4 inches long, killed
and swallowed a 7.9-inch brook trout. Another
slightly smaller snake killed a 7-inch trout. The
third snake released its still living prey and es-
caped.

Following the random observations on
predation, selected isolated pools were checked
daily. The watersnakes continued to wipe out a
large proportion of the adult trout which were
trapped there. The pools generally contained
greater numbers of blacknose and longnose dace,
common shiners, suckers, sculpins, and darters
than trout. It was surprising, therefore, to find
that the snakes took the adult trout in marked
preference to the other species. The trout may
have been more susceptible to capture than the
other fish because of their lethargy in the warm
water . Also, the trout were larger than the other
species, with the occasional exception of hog
suckers and white suckers. Their size may have
been a factor in attracting the predators since
Lagler and Salyer (1947) reported finding brown
trout up to 8.5 inches long in the stomachs of
watersnakes .

American eels occur commonly in several
streams, particularly on the east side of the park.
On the possibility that they prey on trout, dozens
of specimens from 14 to 33 inches long were cap-
tured and opened. Most of the stomach contents
consisted of crayfish. One eel, 24 inches long,
had eaten an 8 -inch trout.

There was no evidence that other preda-
tors were as damaging as watersnakes to trout
during the summer drought. Herons were ob-
served rarely, but kingfishers were more abun-
dant than usual along the streams . We concur
with Larimore, Childers, and Heckrotte (1959)
that predators can and do remove large numbers
of fish from shallow pools during periods of dis-
continuous flow.

Trout spawning:-- The autumn droughts
in 1951, 1952, and 1953 seriously affected spawn-
ing. Brook trout in the park spawn during the
last week of October and the first week of Novem-
ber . In the years mentioned, many of the riffle
areas were dry or were completely choked with
fallen leaves. The trout in isolated pools made
many redds, most of which were incomplete ,
Those redds at the sides of pools were often left
dry by shrinking water levels . The survival of
ova in some redds may have been jeopardized by
the reduced exchange of ground water . Further-
more, our collections demonstrated that the dis-
tribution of sexes in the isolated pools was very
unequal . Thus, recruitment during the three
successive years was small .

Floods

As so often happens, severe flash floods
interrupted the droughts. Furthermore, they
damaged the declining trout populations. Follow-
ing a dry winter, 4 . 5 inches of rain caused flash
floods to sweep the streams on March 1, 1954.
The long, summer drought the same year was
broken on October 15 by the disastrous Hurricane
Hazel which dumped 9 inches of rain on the park
headquarters area. Some watersheds received
up to 17 inches of rain in that storm. Hurricanes
Connie and Etoanne added to the flood damages in
August 1955 with 4.6 and 8.8 inches of rain
respectively.

Scouring: - - The steep watersheds proved
to be hi^ly susceptible to damage by flash floods.
The stream beds were badly scoured, and the
numerous fords on access roads and trails were
washed out. It was impossible to conduct imme-
diate surveys of damages to the streams and
fish until the National Park Service repaired the
impassable roads.

The scouring during the March 1954 flood
was so impressive that we planned to measure
some of the effects of future floods . Boulders of
various sizes in and along the stream beds were
to be marked with paint and their locations plot-
ted on a stream map . Tentative selections
which included very large boulders were made
on Big Run . Before the plan was implemented,
the flood attending Hurricane Hazel swept the
stream, and the selected boulders could not be

found. Indeed, the mile -long section of stream
which had contained the boulders as well as abun-
dant rubble and gravel was scoured to clean
bedrock .

Damage to aquatic life:-- It is known that
floods and scouring cause losses to fish and to
fish food organisms. Quite by accident, flood
pools were discovered in the woods at some dis-
tance from the streams following the March 1954
flood. Sac -fry brook trout, blacknose dace, and
mayfly nymphs were observed in them . The pools
soon dried and the fish and n3anphs were lost.

It appeared that the flash floods are more
damaging to fish and invertebrates when they
follow periods of drought. Then, the fish are
concentrated in pools, and their physical condi-
tion may be poor . Their ability to withstand
floods is thus reduced. The presumption is based
on the fact that water levels and fish were in
better condition in August 1955 when hurricanes
Connie and Dianne struck, and the damages to
the fish were less.

Population estimates

No quantitative estimates of trout popula-
tions were made in 1952 and 1953. Young-of-the-
year brook trout were extremely scarce in seven
streams which were examined in the spring of
1953. The fishing, on the other hand, during the
May 1 - July 10 season that year was fair. Vol-
untary creel census records from 13 streams
showed catch rates which ranged from 0.4 to 1 .0
trout per hour, and the trout averaged slightly
more than 8 inches in length. It was noted, how-
ever, that trout over 10 inches long were less
numerous than in 1952.

The trout were obviously in critical con-
dition in the spring of 1954 following the fall
drought and the March flood. Many appeared
emaciated. Estimates were made of the popula-
tions in seven streams, based on collections ob-
tained with cresol. Only 11 trout over 7 inches
long were collected in 1,500 yards of formerly
excellent trout waters. The estimates ranged
from 1 . 7 pounds of trout per acre in Big Run to
7.7 pounds in Piney Run. Moreover, few young-
of -the -year and yearling trout were found. As a
result, the National Park Service closed all
streams in the park to fishing for the year.

The trout populations were estimated
again in the fall of 1954, shortly after the flood
caused by Hurricane Hazel. The summer
drought and the flood caused demonstrable
losses. There were only 16 trout per acre in
Big Run in contrast with 44 per acre in the pre-
ceeding March. There were losses also among
the smallmouth bass and forage fishes in the
lower section of Big Run . Trout were scarcer in
Jeremys Run and the North Fork Moorman River
than in Big Run, but they were somewhat more
numerous in Hney Run and Rapidan River.

The validity of the estimates of the trout
population in 1954 is, however, subject to ques-
tion. Both the spring and fall surveys immedi-
ately followed flash floods which had terminated
periods of low water . Although the sampling
was extensive, it could not be justified as repre-
sentative of streams which recently had been
largely dry. Furthermore, the sampling gear
an d procedures for soft water streams were
undergoing testing and improvement. We con-
cluded that the estimates for this year were
probably low.

THE RECOVERY OF TROUT POPULATIONS

The small numbers of surviving brook
trout spawned successfully in November 1954.
This marked the beginning of the recovery of
the populations. Water levels remained favor-
able after the hurricane flood, and it was the
first time since 1950 that spawning conditions
were good.

Park streams remained closed to fishing
in 1955 to afford some protection to the few
adult trout in the event of another prolonged
drought. Fortunately, conditions were less se-
vere than in the preceding year .

Stocking

An attempt was made in 1955 to acceler-
ate the recovery of trout populations in 13 of the
46 streams by stocking fingerling brook trout of
the Appalachian strain. The experiment was
prompted by the good results obtained in stock-
ing the same strain in flood-damaged streams
in Great Smoky Mountains National Park and in
Tennessee streams in 1954. A total of 22,089

fingerlings which averaged 2.7 inches long was
stocked in June. Most of them were fin -clipped
to permit future identification .

The fingerlings appeared to thrive until
hurricanes Connie and Dianne brought flash floods
in August. Thereafter, only a few were found .
The survival in Big Run throu^ the summer was
0.7 percent of the 5,500 fish stocked. In contrast,
wild young-of-the-year brook trout survived the
floods relatively well, despite their smaller
size. The stocking was a failure, and none has
been attempted since .

Population estimates

1955:-- The populations of brook trout in
most of the streams improved greatly in 1955
as a result of better water levels which permitted
spawning and good survival. Piney Run, one of
the good streams in the park, is an example
(table 3). There were 115 trout or 8.5 pounds
per acre in the fall of 1954. A year later the
estimate included 418 trout or 34.5 pounds per
acre.

Whereas most of the increase was due to
young-of-the-year fish, there was significant
improvement in the condition and growth of the
older fish . Reflecting the amelioration of food
and water supplies, the coefficient of condition
( R= W X 10 ; Cooper and Benson, 1951)

of 7- to 11-inch trout increased from 1.41 in
1954 to 1.62 in 1955. The latter compares fa-
vorably with Cooper's and Benson's mean
coefficient of 1 . 65 (range: 1 . 40-2 . 1 1) for a
group of 100 wild brook trout collected in the
Pigeon River, Michigan, in 1949. The lengths
of trout captured in Piney Run in 1954 ranged
from 2.9 to 10.4 inches. In 1955, the fish
ranged from 2.4 to 11.4 inches long, and 25.7
percent of them were over 7 inches long.

Good reproduction occurred in most of
the streams during early November. Many
redds with 8- to 12 -inch trout over them were
located. Fertilized ova in excellent condition
were found in selected redds then, and again in
January 1956.

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Some of the trout in Big Run demon-
strated a preference for spawning in the newly
dug gravel which the National Park Service used
to rebuild the fords washed out by hurricanes
Connie and Dianne during the summer. The
preference was most obvious in sections of the
stream where the natural bottom material is
mostly a shalt-type shale type gravel.

1956: --On the basis of the successful
reproduction in 1954 and 1955 and the improved
survival and growth of trout, the park was re-
opened to fishing on May 1. The fishing season
was lengthened to conform with the State of
Virginia season. The regulations included a
9 -inch minimum size, a daily possession lirhit
of 8 fish, and a requirement that only artificial
lures be used. As expected, anglers quickly
removed most of the trout over 9 inches long.

Despite some low water levels in the
spring, the year was favorable for the continued
improvement of trout populations. The hatch of
brook trout was good, and advanced fry collected
in Big Run and Piney Run in late April ranged
from 1.0 to 1,4 inches long. It was noteworthy
that a successful hatch occurred in North Fork
Moorman River for the first time in several
years. Furthermore, rainbow trout spawned
successfully in Moorman River for the first
time.

The large and attractive North Fork of
Moorman River is perhaps the most marginal
of the park trout streams . It is easily accessi-
ble, however, and it receives heavy pressure
from fishermen who reside in the Charlottes-
ville, Virginia, area. It was stocked repeated-
ly with rainbow trout in the late 1940's on the
assumption that this species would do better than
native brook trout in the relatively warm water.
It appears, however, that the rainbows moved
downstream into the Charlottesville Municipal
Reservoir, a short distance out of the park, and
became established there . None was seen in the
North Fork during the severe drought years.
Some large specimens were observed in the
spring of 1955, but no evidence of spawning
could be found. Rainbows up to 20 inches long
moved upstream again in the spring of 1956, and
some successful reproduction took place . An
estimate made in November included 77

young-of -the -year per acre which ranged from
2.3 to 4.7 inches long.

Hogcamp Branch, a remote tributary of
the Rose River, contained a contrasting abun-
dance of trout. It was one of the very few streams
in the park which escaped the damaging effects
of the droughts and floods . Furthermore, it had
a good population of brook trout before the fish-
ing seasons were closed for two years . There
were 2,679 trout or 165 pounds per acre in the
fall of 1955. They ranged from 2.4 to 10.4
inches long, and 15 percent were over 7 inches
long (table 4). This was, by far, the largest
population which has been found in the park .

Hogcamp also provided an example of
the impact of heavy fishing pressure on a small
stream. The stream was fished hard in 1956,
and the larger fish were removed. Most of
the 2,125 trout found per acre in the fall were
young-of -the -year and yearlings, and the weight
of trout per acre had dropped to 50.8 pounds.
Less than 3 percent of the fish were over 7 inches
long, despite the fact that the minimum legal
size was 9 inches.

The population estimates for 1956 in
table 3 are misleading in one respect. We at-
tempted as far as possible to base the estimates
on collections which were made at the same sur-
vey stations year after year. Supplemental
surveys in the fall of 1956 disclosed that brook
trout were again present in the extensive areas
of mainstream, headwaters, and tributaries
which had been dry in 1954 and barren in 1955.
Thus, we concluded that the populations had im-
proved greatly in numbers and distribution even
though the estimates do not demonstrate the
fact. Big Run, for example, shows a decline
in 1956, part of which is attributable to fishing.
There was, however, a large movement of trout
into the barren headwaters and tributaries which
reduced the numbers and pounds of trout in the
mainstream .

1957:-- The over -winter survival and
growth of trout was checked in several streams
in April. The survival of fingerling brook trout
was good, but their growth since the previous
November was small. The survival and growth
of fingerling rainbow trout was very good in the

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11

North Fork Moorman River. They averaged
3.5 inches long on November 29, 1956, and 5.5
inches on April 12, 1957.

The eastern seaboard region from Vir-
ginia northward experienced another drought
during the summer and early fall (table 2).
Streams in the park once again became very
low or intermittent, and water temperatures
were high.

The surveys made in December demon-
strated that the numbers of trout had decreased
(table 3). On the other hand, the weight of trout
per acre had increased in some streams and
decreased in others. An examination of the
length-frequency distribution of trout disclosed
that there were far fewer young-of -the -year
trout than in 1956 (table 4). The smaller num-
bers were the result of poor survival conditions
in the summer and the fewer spawners in the
fall of 1956. As mentioned previously, the lar-
ger adult trout responsible for the abundant
reproduction in 1955 were cropped during the
1956 fishing season.

1958:-- Estimates of the fish populations
were made only in the spring, and the surveys
included 22 streams which were not studied pre-
viously. We sought to determine whether the
trout had recovered from the disastrous droughts
and floods. One or more survey sites were
located on each stream . Where only one site
was possible, it was located on the lowermost
section or most accessible section. We assum-
ed that if trout were found at these sites, they
would be present in equal or greater numbers
upstream or in the more inaccessible sections.

The numbers of brook trout in 16 of the
22 streams ranged from a few to 851 fish per
acre. Young-of-the -year trout, 0.9 to 1.5
inches long, were observed in most of them .
Although no trout were seen or collected in 6
streams, it would be unsafe to conclude that
they do not exist in the upper waters.

1959: --Sixteen new streams were in-
cluded in the surveys. Three were barren of
trout, and the estimates for the others ranged
from 16 to 1,744 trout per acre. The populations
were relatively good in the 5 streams which

had been surveyed in previous years . The data
indicate that of the larger and more heavily
fished streams. Big Run, Piney Run, and Rapidan
River are better producers of trout than the North
Fork Moorman River .

Growth of trout

The growth of brook trout was relatively
rapid during the period of population recovery.
Henderson (1950) listed the ages of brook trout
which he collected in Shenandoah streams in the
fall of 1950. The trout were abundant at that
time, and their growth was slower than that of
trout we collected in 1956-57. For example,
among the trout sampled in Big Run, age II fish
ranged from 4.0 to 7.9 inches long in 1950 and
from 6.0 to 10.9 inches long in 1956-57. Age III
fish ranged from 5.0 to 9.9 inches in 1950 and
from 8.0 to 12.9 inches in 1956-57.

In general, the growth of brook trout was
more rapid in the warmer streams. Thus, trout
in the North Fork Moorman River and Big Run
grow slightly faster than in Piney Run. Rainbow
trout also grew well in the North Fork . The
1956 year class averaged 3.5 inches in November
of that year and 7.8 inches long in December
1957.

Furthermore, two-year-old brook trout
in park streams in April 1957 ranged from 6.0
to 12.9 inches long whereas 35 wild trout of the
same age from a productive New Hampshire
stream in July 1957 ranged from 6.0 to 9.9
inches . Most of the Shenandoah fish were in the
9.0-9.9-inch group and most of the New Hamp-
shire fish were 7.0-7.9 inches.

Among 86 legal size, brook trout
(9.0-12.9 inches long) which were captured by
anglers or during surveys on Big Run and Piney
Run in 1956 and 1957, 23 trout were beginning
their third summer; 57 their fourth summer;
and 6 their fifth summer. No 5 -year -old fish
were taken by us at any time.

12

THE SPORT FISHERY

Creel census

Season and regulations

Upon the reopening of fishing in 1956,
the season was lengthened to correspond to that
of the State of Virginia. It now opens in early
April on the same date as the State, and it
closes on the same date as the State, or on Oc-
tober 15, whichever is the earlier.

A Virginia license is required in the park
and, until recently, the high cost of a non-
resident permit deterred many tourists from en-
joying the fishing. Now a short-term permit
is available to non-residents at a lower cost.
Only artificial lures are permitted; the daily
bag limit is 8 trout; and the minimum legal size
is 9 inches.

A 9-inch minimum size was adopted as
a compromise between recommendations for
fishing-for-fun-only and the renewal of the pre-
vious 7-inch limit. It was applied primarily to
protect the spawning potential, especially during
the recovery years . It also serves to improve
the sporting aspects of trout fishing, as demon-
strated on the North Branch of the Au Sable River
in Michigan (Cooper, 1951). Although the high-
er size restriction cuts down the yield of trout
to fishermen, such yield is, and must continue
to be, of secondary importance in Shenandoah .

The trout resources and the sport fishery
can be preserved best by applying a fishing-for-
fun-only program on the streams such as has been
tested on selected streams in Great Smoky Moun-
tains National Park (Lennon and Parker, 1960).
The program would be especially appropriate in
Shenandoah, and a start in this direction was
made in 1961. Under terms of an agreement be-
tween the park and the State of Virginia, the
headwaters and tributaries of the Rapidan and
Staunton rivers were opened to fishing-for-fun
(Sheridan, 1961). All trout captured must be
returned to the water immediately . Although
only months old, the program has been called a
success from the standpoint of angler participa-
tion and fishing quality (Birchfield, 1961 and
Yeager, 1961).

The streams in the park are not subject
to the fishing pressures which are typical of
northern trout waters. In general, the pressure
is relatively heavy during the first several days
of the season. Thereafter, the drop is so sharp
that one must search for fishermen. For ex-
ample, there were 38 fishermen on the 5 -mile
long Big Run on May 1 and 2, 1956, when the
park was reopened to fishing. On Memorial Day,
there were only 7 anglers on the stream . On
opening day in 1957, 28 fishermen were counted
on the stream . On the same day, park rangers
counted only 191 fishermen on 17 streams.
Within a few days after the openings, fishermen
were also scarce on the State -managed trout
waters beyond the park boundary.

It appears that the average fisherman in
the Blue Ridge region fishes for trout several
times immediately after the season opens and
then devotes his efforts to the abundant warm
water fisheries in larger waters. Only the rel-
atively few avid trout fishermen frequent the
mountain streams throughout the season.

Limit catches of 8 trout are rare. We
checked anglers during their fishii.g who had up
to 6 legal trout. Most of the fishermen expressed
approval of the 9-inch minimum size and satis-
faction with the quality of fishing. They stressed
that fewer 9- to 14 -inch wild trout in the creel
were preferable to several more 7 -inch wild
trout .

Management aspects

Wild brook trout occur in at least 37 of
the 46 streams . No trout were found at the sites
surveyed on 9 streams, but we cannot conclude
that they are barren of trout. The exotic rainbow
trout is established in the North Fork Moorman
River, but the population is small. Smallmouth
bass and redbreast sunfish are found in the lower
courses of a few streams, but in such small num-
bers that they are of no importance in the sport
fishery . Thus, management should be directed
almost exclusively to the brook trout.

The outstanding factor which influences
the trout populations and the sport fishery is the

13

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

years. The short, steep streams are partic-
ularly vulnerable to drying during droughts and
to severe scouring during flash floods . These
factors influence the sport fishery much more
strongly than fishing regulations or fishing
pressures. Thus, from a long-range point of
view, the streams are considered marginal for
trout, and they must be managed as such.

ACKNOWLEDGEMENTS

The assistance of the following persons
in the planning, conduct, and reporting of the
study is gratefully acknowledged: Dr . Willis
King and Mr. Phillip S. Parker, U.S. Fish and
Wildlife Service; Superintendent Guy Edwards
(retired). Superintendent R. Taylor Hoskins,
and Mr. O. L. Wallis, Aquatic Biologist, Na-
tional Park Service; and Mr. Robert G. Martin,
Chief, Fish EJivision, and fishery biologists of
the Virginia Commission of Game and Inland
Fisheries.

I am grateful also to Messrs. Robert G.
Piper, Howard N. Larsen, and Donald F. Mairs,
U.S. Fish and Wildlife Service, for their critical
review of the manuscript.

LITERATURE CITED

Birchfield, Jim

1961. No fishing for keeps. TTie Washing-
ton Star Sunday Magazine, May 28,
pp. 4-5.

Cooper, Edwin L.

1951 . Every trout a trophy. Michigan
Conservation, March -April, pp.
14-18.

Cooper, Edwin L., and Norman G. Benson

1951. The coefficient of condition of brook,
brown, and rainbow trout in the Pigeon
River, Otsego County, Michigan.
The Progressive Fish-Culturist, vol.
13, no. 4, pp. 181-192.

Embody, G. C.

1921. Concerning high water temperatures
and trout. Transactions of the Amer-
ican Fisheries Society, vol. 51, pp.
58-64.

Kendall, William C, and Wilford A. Dence
1927. A trout survey of Allegany State
Park in 1922. Roosevelt Wild Life
Bulletin, vol. 4, no. 3, pp. 289-482.

Lagler, KarlF., and J. Clark Salyer, II
1947. Food and habits of the common
watersnake, Natrix s. sipedon, in
Michigan. Papers of the Michigan
Academy of Science, Arts and Letters,
vol. 31, 1945, pp. 169-180.

Larimore, R. Weldon, William F. Childers,
Carlton Heckrotte

1959. Destruction and re -establishment
of stream fish and invertebrates
affected by drought. Transactions of
the American Fisheries Society,
vol. 88, no. 4, pp. 261-285.

Lennon, Robert E . , and Phillip S . Parker

1957. Electric shocker developments on
southeastern trout waters. Trans-
actions of the American Fisheries
Society, vol. 85(1955), pp. 234-240.

1958. Applications of salt in electrofish-
ing. U.S. Fish and Wildlife Service,
Special Scientific Report - Fisheries
no. 280, 11 pp.

1960. The fishing-for-fun program on
trout streams in Great Smoky Moun-
tains National Park. Proceedings,
Society of American Foresters, Wash-
ington, D.C., pp. 106-112.

Petty, A. C.

1955. An alternate -polarity electrode.
New York Fish and Game Journal,
vol. 2, no. 1, pp. 114-119.

Sheridan, Jack

1961. Fish for fun. Virginia Wildlife,
Virginia Commission of Game and
Inland Fisheries, vol. 22, no. 5,
pp. 16-17.

Wilkins, L. Price

1955. Observations on the field use of
cresol as a stream survey method.
The Progressive Fish-Culturist,
vol. 17, no. 2, pp. 85-86.

15

Yeager, Lee E.

1961 . Virginia's trout are headwaters
fish. Virginia Wildlife, Virginia
Commission of Game and Inland
Fisheries, vol. 22, no. 7, pp. 8-9.

INT. DUP.,D.C. 61-1 01-0 61

16

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