TROUT MOVEMENTS
ON DELAWARE RIVER SYSTEM TAIL-WATERS IN
NEW YORK STATE
Scott Douglas Stanton
BIOLOGICAL FIELD STATION
COOPERSTOWN, NEW YORK
Occasional Paper No. 34
September 2000
STATE UNIVERSITY COLLEGE
AT ONEONTA
ABSTRACT
In order to detennine the cause of trout movements throughout the Delaware and Beaverkill
river systems, a radiotelemetry study, funded by Trout Unlimited (TU) in cooperation with the New
York State Department of Environmental Conservation (DEC), was undertaken. In the 1995 year
long pilot study, a group of 55 trout, composed of both rainbow and brown trout, were tagged. The
fish tagged were found throughout the Beaverkill River, the East Branch of the Delaware River
below the Pepacton Reservoir, the West Branch of the Delaware River below the Cannonsville
Reservoir, and the main stem of the Delaware River below Hancock, New York. In 1996, 56 trout
were similarly tagged throughout the same system. In 1997, only one more fish was tagged.
The overall goals of this study were to track migration related to seasonal spawning and to
detennine the extent of use of tributaries for this spawning. Seasonal movements were also tracked
during the wanner months of the year, when certain waters become too wann and potentially force
trout to seek cooler thennal refuges present in the river system.
The sections of the East and West Branches of the Delaware River, which lie below the New
York City Watershed Reservoirs, are tailwater fisheries. Trout there are dependent on cold water
releases from these reservoirs throughout the entire year. The West branch receives strong cold
water releases of350-600 cubic feet per second (cfs) periodically throughout the year, compared to
the East branch of the Delaware which only receives 90 cfs (McBride, 1997).
Throughout the summer and fall of 1995, trout movement took place throughout the entire
watershed, as the fish seemed to seek cooler refuges in relation to the wann water temperatures.
Trout tagged in the West Branch of the Delaware remained there throughout the summer, as the cool
water releases from the Cannonsville Reservoir kept the water temperatures suitable for their
survival. Both brown trout (Sa/mo trutta) and rainbow trout (Oncorhynchus mykiss) showed
movement throughout the entire system in the spring and the fall of 1995, and utilized various
tributaries for spawning.
In 1996, tagging was changed with respect to the number of tags placed in each river. With
the West branch fish known to remain stationary throughout the year, fewer tags were used in this
area in the continuation in 1996. A greater number of tags were put out in the lower East Branch of
the Delaware, the main stem of the Delaware, and the Beaverkill River in an effort to study the
movements of the trout as the waters there became wann in the summer months.
The summer of 1996 showed very different water temperatures than those found in the
previous summer. Water levels remained high throughout the season, and trout remained stationary
with only slight movements due to sudden discharge releases. Certain fish did show movements in
relation to highly turbid water associated with steady heavy rain, and the overflow of both reservoir
systems.
Fall 1996 temperatures cooled the waters again. Water levels in both systems were very low
during the months of September and October due to drawdown releases of both the Pepacton and
Cannonsville Reservoirs. Discharges as of mid October were at about 35 cfs out of Cannonsville,
and steady 90 cfs out of the Pepacton Reservoir (McBride, 1997).
11
Brown trout began to move during the fall spawning run with fish from the East branch,
Beaverkill, and Delaware River all utilizing various tributaries throughout the watershed. Brown
trout within the West Branch had moved up the river and into areas of gravel, which provides ideal
spawning habitats.
In 1997, the third year of the study, only one more new fish was tagged. This was a two­
year-old female brown trout. This fish was hatchery raised, and tagged purposely in order to
determine the migratory action of a fish raised in a hatchery environment. As expected, this fish
remained stationary.
..
111
CONTENTS
ABSTRACT
.i
INTRODUCTION
1
SAMPLE AREA
Description
Discharge
2
3
4
METHODS
Tagging ofFish
5
7
RESULTS
Migration ofTrollt.
West Branch of the Delaware River
Movement Related to Water Temperature
Movement Related to Spawning
Main Stem ofthe Delaware River.
Movement Related to Water Temperature
Movement Related to Spawning
East Branch of the Delaware River..
Movement Related to Water Temperature
Movement Related to Spawning
Beaverkill River
Movement Related to Water Temperature
Movement Related to Spawning
12
12
16
16
17
19
19
22
24
24
27
29
29
30
CONCLUSIONS
Thermal Refuges
Spawning Streams
31
33
34
LITERATURE CITED
36
APPENDICES
39
INTRODUCTION
Following a feasibility study from mid April to the end of May 1994, conducted by
NYSDEC, a pilot study was initiated in 1995 on the Delaware River tailwaters and the
Beaverkill River. This study was to determine the causes and timing of trout movements
within this system, encompassing these two rivers. Funded by the New York State
Department of Environmental Conservation (DEC) and Trout Unlimited (TU), the study was
continued in 1996 and 1997. The goal was to gain insight into different aspects of the
migration of the trout species involved. Migration related to seasonal spawning, and the
extent ofthe use oftributaries for spawning was determined, as well as the identification of
critical habitats. Rainbow and brown trout, both hatchery raised and wild, were used in the
study. The extent to which migration is affected by factors such as water temperature and
the urge to spawn was considered.
Both funding organizations, the NYSDEC and TU, were interested in supporting the
study in hopes that a better understanding could be reached regarding the trout resource in order
to manage it more productively and to protect it as a wild fishery. These organizations also
strive to keep the waters bountiful for the many anglers who utilize the watershed for sport
fishing and enjoyment.
The Delaware River tailwaters are located below New York City Watershed Reservoirs,
and are managed and regulated as a world class trout fishery. The goal of this particular study
was to locate prime spawning areas and determine seasonal movements and locations of trout in
the system in relation to water temperature and spawning. By determining the spawning
movements related to fish migration, as well as locating prime spawning areas, the rivers can be
better managed as trout fisheries. By discovering what does, or can, affect the migration of
rainbow and brown trout, we are better able to design regulations to be put into effect in areas to
improve propagation. These regulations should be in areas where they can best protect these
fish, their spawning locations, nursery areas in tributaries, and also cool water refuge areas
during the low summer flows.
Locating prime spawning areas within the river system will allow management practices
to be tailored to protect these areas. It will also document prime spawning locations and allow
yearly recruitment of the young of the tracked rainbow and browns, which can then become the
brood stock for the Delaware River system. By locating these areas, regulations can be created
to protect the tracked fish so that the survival of young trout is insured, or increased. Secondly,
due to the trouts' movement into specific locations, areas of cool water refuge can be determined.
These are the usual places to which trout can relocate in order to survive the hot, dry summer
months. It is during this time that the river is under low discharge conditions requiring releases
from the reservoirs. By locating these refugia, releases can be timed to provide considerable
benefits to the trout.
The Delaware River watershed consists of both the West and East branches of the Delaware
River, the main Delaware River, and the Beaverkill River. This watershed is managed as a trout
fishery. Anglers from across the country fish the Delaware River system because of the number
offish, as well as the quality of the sport of fishing. The West branch and the main stem of the
Delaware River are managed for wild fisheries, without any stocking taking place. The East
branch and the Beaverkill River are both stocked fisheries.
SAMPLE AREA
The sample area included the watershed encompassing parts of the Delaware and
Beaverkill rivers. This complex system covers an area of243.1 km (l51 river miles) and
displays virtually every characteristic that can be found in such a system. By encompassing the
entire watershed, data gathered would be more reliable and cover a broader spectrum of
characteristics and factors. See Figure 3.
N
I
l
I
w
l
E
8
0
L ....
S
10
IS
I
,
!
"'\,Iets
Figure 3.
Salnple Area Used in Study
2
3
The East Branch of the Delaware can most easily be thought of as two river parts, the
upper and lower East branches with the Beaver Kill confluence acting as the dividing line. The
upper East branch flows from the Pepacton Reservoir dam for 27.36km (17 miles) before
meeting with the Beaver Kill. The Beaver Kill runs 24.l5km (15 miles) from its point of
junction with the Willowemoc Creek. The lower East Branch flows for 24.l5km (15 miles)
from the town of East Branch, NY, where the Beaver Kill meets it, to the town of Hancock, NY.
The West branch of the Delaware originates at the Cannonsville Reservoir and runs for 89.76km
(17 miles) before merging with the East branch. At that point it is known only as the main stem
of the Delaware River. The upper l6.42km (10.2 miles) are located in the state of New York
while the lower l2.07km (7.5 miles) of river form the boundary between the states of New York
and Pennsylvania (McBride, 1997).
The waters of these rivers vary in nature. The Beaver Kill is a Catskill freestone. This
means that the stream is a naturally flowing water body without any artificial impoundments,
such as a dam. The lower reaches of the Beaverkill are susceptible to thermal stress during hot
weather. The temperatures here have been known to reach 27 C(80 F). Stream widths average
30.49m (100 ft) near Roscoe and 42.68m (140 ft) at the mouth near East Branch (Sanford, 1991).
Stream gradient is 7.32m/16.09km (24 ftlmi.) between Roscoe and Horton, and is 3.96
m/16.09km (13 ft/mile) from Horton to East Branch (McBride, 1997). Wild and stocked brown
trout populate the Beaver Kill as well as a few rainbow and brook trout. The Upper East branch
tailwater resembles a large spring creek. It is a low gradient stream of 1.98m/16.09 km (6.5
ft/mile) characterized by large stretches of flat water which make for poor trout habitat
(McBride, 1997). It receives a cold bottom release from the Pepacton Reservoir. The river
averages 24.39m (80 ft) near Downsville and 41.54m (135 ft) wide above the confluence at East
Branch (Sanford, 1993a). It possesses a strong wild brown population, as well as a stocking of
yearling browns. Approximately 6,000 brown trout yearlings are stocked into each of the four
reaches of the river, numbering 24,000 (Mc Bride, 1997). There are also small populations of
brook trout and rainbow trout in the Upper East branch.
The lower East branch is very similar in nature to the Delaware's' main stem. The
average width increases from 61.59m (202 ft) below the confluence at East Branch to 87.8m
(288 ft) in Hancock (Sanford, 1993a). It is very susceptible to thermal stress with summer water
temperatures rising into the 27 C (80 F) area. There are tributary inputs, as well as some springs,
which serve as critical cold water refuges. In particular, strong groundwater infiltration between
East Branch and Fish's Eddy creates summer thermal refugia which can sustain the adult brown
and rainbow trout populations on a year- round basis (Sanford, 1989). These fish are thought to
be nomadic, moving away during the hot summer months, and returning when the water cools in
temperature, usually during the fall months.
The West branch consists of 27.3 7km (17 miles) of riffles and pools. It is a low gradient
stream 2.23m/16.09km (7.3 ft/mi.) characterized by long stretches of flat water broken by
moderate flow and riffles around the many islands found within. The average width is about
60.98m (200 ft) near Deposit and 73.78m(242 ft) near Hancock (Sanford, 1993b). It runs cool
throughout its entirety due to large cold water releases from the Cannonsville Reservoir. This
branch has the largest population density of wild brown trout, with rainbow trout in its lower
reaches, and is not stocked.
4
The main Delaware River is a huge expanse of pools and riffles. The Delaware flows for
5l6.7km (321 miles) before entering the Atlantic Ocean. The main stem runs for 43.46km (27
miles) downstream to the town of Callicoon. This is the section referred to in this study. The
width of the Delaware is much larger, and averages 109.76m (360 ft) (Sanford, 1993b). It
experiences thermal stress in the summer months, and depends upon the releases from the
reservoirs, mainly Cannonsville, to allow it to support the trout fishery. The Delaware is not
stocked, and supports a wild rainbow trout fishery.
Discharge:
Discharges of water into the watershed affect the temperature and quality of the waters
throughout the entire Delaware River tailwaters system. Thermal releases from Cannonsville
Reservoir on the West Branch provide cool water year round. This also maintains the quality of
the water. With cool thermal releases, both dissolved oxygen and water temperatures remain at
beneficial levels for optimum trout growth and survival. Water releases throughout the warm
summer months provide suitable conditions for trout to be active and healthy. Cold water
releases also keep baitfish and insect populations active, thereby providing trout with an ample
food supply year round.
Release schedules are set for the reservoirs in an effort to keep water temperature at
optimum ranges for trout growth and survival (McBride, 1997). The West Branch of the
Delaware River originally received release flows of 33 cubic feet per second (cfs) during the
winter and summer flows of 325cfs. Under new release flow programs implemented by the
Delaware River Basin Commission and the City of New York, new flow release schedules took
effect in 1997 (McBride, 1997). The water flow rate was increased from 33 cfs to 45 cfs flow
from mid September to May. The summer release of 325 cfs usually ran from June 15th to
August 15th. It was changed to 160 cfs, and runs from June Ist through September 15th.
The East Branch receives a constant flow from the Pepacton Reservoir of 90 cfs year
round. This allows the upper East Branch to stay cold year round, and trout thrive in this area.
Once water reaches the lower East Branch, flows are too warm for trout survival in the summer
months.
The Beaverkill River System is a freestone river without any cold water releases. Flows
within the Beaverkill are solely dependent on runoff from the watershed. Flow rates are usually
very good throughout the spring and early summer months, but during late summer and fall the
Beaverkill suffers from very low, warm conditions, causing trout to leave the system in search of
cooler water.
5
METHODS
Migratory behavior of the fish in this study was detennined by the use of radio telemetry.
Radio telemetry is well suited for shallow, low conductivity fresh water and also for very
turbulent water. The use of radio telemetry is also excellent for searching large areas to find
highly mobile species, like trout and salmon (Winter, 1983). Though radio telemetry is costly,
involves invasive surgery, and is restricted to those fish captured and put into use, it does enable
an observer to unobtrusively locate fish in most habitats (Winter, 1983).
Small, surgically implanted radio tags were placed into the abdominal cavity of38.1­
50.8cm (15-20 inch) rainbow and brown trout (Ross and Kleiner, 1982). The fish were captured
by either angling or electroshocking. Fish were anesthetized using MS-222 anesthetic, and a
small incision was made just ahead of the ventral fin (Schreck and Moyle, 1990). The tags were
then inserted into the abdominal cavity. The antenna, a 30.5cm (12- inch) long strip of Teflon,
was left trailing out of the fish just ahead of the anal opening. The fish were then revived and
released. (A more detailed discussion follo~.) See Figure 1.
1'ransnli.tter
Fig'Jre l..
A radiotagged trout, sbQwblg placement oCtrausmitter
6
Radio telemetry systems usually operate from 27-300 megahertz (MHz). In an
underwater radio transmitter, an oscillator circuit produces electromagnetic vibrations at a given
frequency determined by a crystal. These vibrations are then transformed into signals which are
transmitted through a loop or straight wire antenna (Winter, 1983). An oscillating, or scanning,
receiver receives the signals (Nielsen and Johnson 1983).
In this particular study, each radio tag was a Model 2 transmitter manufactured by
Advanced Telemetry Systems Inc. Each measured 5.56cm (2.19 inches) long by 1.27cm (0.5
inch) in diameter, weighed ll.34g (0.4 oz), and had a different frequency between 52.0 and
53.999 MHz. A 3-V lithium battery powered the tags. The antennas used were straight wire,
measuring 2.54cm (12 inches) in length. Each fish was implanted with a tag, which had its own
independent operating frequency. The radio tags were activated daily for a ten-hour period and
then shut off automatically for the next fourteen-hour period. The radio transmitters used in
this study were also temperature sensitive, allowing the tag to document the temperature of the
water at each fish's location. Temperature, in degrees Celsius (C), can be determined by timing
a set number of pulses received. In this particular study, an interval often pulses was chosen. A
stopwatch was used to find the time elapsed between the first pulse heard and the beginning of
the eleventh pulse- signaling ten elapsed pulses. This value, when multiplied by 100 finds the
period reading in milliseconds. Once this number is found, a chart is used as a reference, which
contains pre-calculated water temperatures (see Figure 2). The far-left column of the chart is
a listing of temperatures in degree C. The temperature values are shown in tenths, and
continue along the top row of the chart. The body of the chart consists of periods in
milliseconds. To find the temperature which corresponds to the period, you find the period
(or the number closest to the period) in the body of the chart. Next, follow the row to the far
left column. This yields a number. Then, follow the column to the top from the period. This
yields a second number. Adding the two numbers gives you the exact temperature. A
separate chart is used for each transmitter frequency (Advanced Telemetry Systems, 1995).
At each fish location a river temperature was then taken to determine if the fish is in warmer
or cooler water than the temperature determined by the tag. This is called the actual or
ambient river temperature. In order to gather this data, it was necessary to wade out into the
main current in the riffle area, at least 3.05m (ten feet) from shore, and measure temperature
with a hand held, calibrated thermometer.
Temperature sensitive tags such as the ones used in this study provide both
environmental and physiological parameters related to each fish location. This further allows for
understanding animal adaptations and requirements for survival (Winter, 1983).
7
Tagging of Fish
Fish were captured by either angling or electro-fishing. Capture location, water
temperature, date and time of capture, age, sex, length and weight of the fish, and whether it was
wild or hatchery raised were noted (see Figure 4). Each fish was given a specific number suffix,
and a lettered prefix corresponding to the river of origin and capture location, therefore
identifying each specific fish. Appendices A; B, C, and D list specifications of each fish radio­
tagged in the study.
R iva r _ _
Fish Number
...JM--I.I_I\~I"';'V\.l.-_j)""",-.;:o;~;..:I""'_~~..J.I...:::.V_~;;..;Y_---:-
hI! /1-2-
1</
Species
Tag Implanted By
5),IeJ~
_...:..Lf...;;.,b_:l
__
_--lo<Jy.)...;./_5".....1..9....;.
. k,"",--
Collection Method
Comments
Len g t h
.LDYJ Fddt
Location Tagged
D ate Tag 9 e d
Tag Frequency
I
_
Weight
/030
/(jc~0~
/
Time Tagged_~
Water Temperature
30
()
£ltc+yo-HShl")
Fre-o{
rcCLC
of
dorSctl-
Figure 4.
Data Form used for each fish tagged in study
The fish collecting via electro-fishing was done out of a specially equipped boat which
carried a Smith Root variable pulsator which was used to rectify AC (alternating current) to DC
(direct current). It provided 1,061 volts (V) at a pulse rate of60 amperage (amps). Amperage to
the water was typically 3.1 +0.2 amps (McBride, 1997). A probe connected to the pulsator was
then placed into the water, conducting the electricity into the surrounding water. The current
effectively stunned the fish in a 70.87cm-94.49cm (15 to 20 ft) radius. The fish were then
collected with nets. When angling, only artificial lures were used in an effort to minimize stress
and mortality to the captured fish. Had live bait been used, the fish would have swallowed the
bait and been damaged by the hook.
Once the trout were captured, they were placed into a solution oftricaine methane
sulfonate (MS-222) anesthetic. The solution caused the fish to lose their equilibrium. Once this
occurred, they were removed and placed on a measuring board. Data was collected from each
fish. The fish was then placed on a foam surgical table developed for a similar study (Courtois,
1981). SeefigureS.
8
Figure 5.
L.A. Courtois surgical table
A scalpel was used to make a 2.54cm-3.18cm (1.0-1.25 inch) incision into the fish's
abdominal cavity, just anterior of the pelvic girdle and slightly to the right of the fish's ventral
midline. The radio-transmitter was then inserted through the incision. The transmitter's
antennae was then passed out through a .38cm (0.15 inch) incision between the pelvic girdle and
the anal opening, using the shielded needle technique designed by Ross and Kleiner (Ross and
Kleiner, 1982). The antennae trailed under and behind the fish's exterior. The surgical incision
was then closed with a .3cm (0.75 inch) curved needle and a monofilament suture, making four
or five stitches (McBride, 1997).
Throughout the surgery, the gills of the fish were irrigated with a solution of stream
water and anesthetic. After surgery, fish were returned to their capture location in an area oflow
stream current. This allowed each fish to regain its equilibrium and eventually swim away into
deeper water. Actual surgery and recovery time took approximately 15 minutes per fish. See
figure 6.
9
Figure 6.
Trout in place on slirgical table, showing transluitter
placement
Tags were implanted into trout from April through October in 1995, and from March
through June in 1996. The single tag in 1997 was implanted on June 3. Tags were programmed
to transmit continuously for 10 hours when activated, and then shut down for 14 hours every day
(McBride, 1997). From April to October, tags were activated between 8am and 6pm daily.
From November until March, tags transmitted from 7am until 5pm daily.
The radio-transmitters also measured water temperature, as discussed. Each was
individually calibrated by Advanced Telemetry Systems to operate most accurately at
temperatures between 10 C and 26 C (50-80 F). The battery of each transmitter was guaranteed
to transmit a signal for 300 days, although half of the tags were expected to transmit for up to
500 days (McBride, 1997). See figure 7.
10
Figure 7
Author using hand held antennae to locate tagged trout
Trout locations were monitored using a scanning receiver and a loop style antennae. All
of the frequencies were entered into the memory of the receiver, and it was programmed to
continuously scan through all of these frequencies. As the receiver scanned through the
frequencies a pulse was picked up which corresponded with a particular frequency. A signal was
heard through the headphones attached to the receiver. As the antennae got closer to the tag, the
signal became louder, indicating that I was very close to the fish's location. I would get out of
the vehicle and venture closer to the water to locate the fish and take the water temperature.
Once the fish's location was documented, it was deleted from the scanning program in the
receiver. Fish locations and the distances they traveled were monitored two days a week during
the winter months and three or four days a week during the warm summer months and spawning
seasons. The monitoring of the locations of each fish was done by either traveling the roads
adjacent to the rivers, or by floating a river section in a McKenzie style drift boat. The location
of each fish, the date located, discharge flow in the area, temperature of the water, and the time
of day were recorded.
The number of fish radio-tagged in 1995 was 50. Twelve brown trout were tagged in the
Beaverkill River, eight brown trout in the Upper East Branch, and three each of brown and
rainbow trout in the lower East branch. Sixteen brown trout and five rainbow trout were radio­
tagged in the West Branch of the Delaware River, and one brown trout and seven rainbow trout
were tagged in the main Delaware River. Because some of the tags were reused, actual numbers
11
included in the data, total 55 radiotags. If a fish was caught or found, anglers returned the tag to
the DEC and it was reused in a different trout. Scale samples of each fish tagged in 1995 were
taken in order to get an accurate count ofthe numbers of hatchery raised and wild trout within
the sample. Based on this scale sampling collected on the 1995 radio-tagged trout, it was found
that 50% of the Beaverkill fish, 7% ofthe East branch fish, 15% of the West branch fish, and
none of the main stem Delaware fish tagged were of hatchery origin (Langan, 1996).
Of the 55 tags fielded in 1995, 15 rainbow trout were tagged. Seven of these rainbows
were 3 years old, four were 4 years old, and four were 5 years old. All rainbow trout tagged
were wild fish. A total of 40 brown trout were tagged. Three were hatchery-raised 3 year olds,
eight were wild 3 year olds, 11 were wild 4 year olds, four hatchery-raised 4 year olds, eight
wild 5 year oIds, and one hatchery-raised 5 year old brown. Five wild brown trout were 6 years
old.
Of the 56 radio-tagged fish fielded in 1996, 19 were rainbow trout. Six of the rainbows
were 3 years old, ten were 4 years old, and three were 5 years old. All of the rainbow trout
tagged in 1996 were wild fish. 37 brown trout were radio-tagged in 1996. Three of the browns
were wild 3 year olds, six were hatchery-raised 3 year olds, 12 were wild 4 year olds, two
hatchery-raised 4 year olds, ·12 wild 5 year olds, and two hatchery-raised 5 year old fish.
The 1996 radio-tag distribution for the entire study area included six brown and one
rainbow trout in the Beaverkill River. In the Upper East branch, there were six brown and one
rainbow tagged. In the Lower East branch, six brown and four rainbows were tagged, and in the
West branch of the Delaware River, eight brown trout and two rainbow trout were radiotagged.
Three ofthe eight brown trout were tagged directly below the dam to act as a control in cold
water release flow from the Cannonsville Reservoir on the West branch. A total of21 fish were
radio-tagged in the Main Delaware River in 1996, all below Hancock, New York. Eleven
browns and 10 rainbows were tagged, and also marked by removing the adipose fin for
identification as a 1996 fish in the sample. See figure 8.
Only one new fish was radio-tagged in 1997. A brown trout from the Beaverkill Fish
Hatchery was tagged and released into the Beaverkill River below Roscoe, New York. This fish
was the only one in the entire study that was taken directly from the hatchery. It was tagged in
order to determine migration activity of hatchery raised fish, and then stocked into a natural
stream environment. The fish was a 2-year-old female brown trout measuring 15 inches in
length, tagged on June 3, 1997 and then released into the Beaverkill.
Water temperatures were very high throughout the entire Beaverkill River system in
1997. Flow levels were low because of the hot, dry summer. Water temperatures, approached
27 C (80 F) on the Beaverkill, and had forced most fish to relocate to thermal cool water refuges.
Gender proportions of both brown and rainbow trout were also documented at the time of
capture. It was necessary to know the sex of the fish in order to compare the movement and
migration differences related to sex as well as origin of the fish involved.
In 1995, there were 18 male fish and 37 female fish tagged. Fourteen males were wild
brown trout, two males were hatchery-raised brown trout, and two males were rainbow trout. Of
the female fish, 17 were wild brown trout, seven hatchery-raised brown trout, and 13 were
rainbow trout.
IIA
N
I
o
""I L E s
Figure 8.
1996 Tagging Locations
71
UPPER
EAST BRANCH
LOWER
EAST BRANCH
BEAVER
WEST
BRANCH
<.~/
N
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.
%"~.:\,~~
I
----­
0
MIL ( S
DELAWARE
RIVER
Figure 9.
Map ofTbermal Refuge Areas
KILL
12
In 1996, 14 male fish and 42 females were tagged. Ofthe male fish, 12 were wild
browns and two hatchery-raised. Fifteen females were wild browns, eight hatchery browns, and
19 wild rainbow female trout were tagged. In 1997, the single fish was tagged.
RESULTS
Migration of Trout
Migration of fish is defined as "movement between two or more distinct and usually
separate habitats, which occurs regularly, is fairly predictable, involves a majority ofthe
population of the species, and is active and directed by the fish" (Northcote, 1991). This
movement is generally cyclical, or a return to habitat occupied by the fish in an earlier life stage.
Migration can be used to describe any movement of a fish, including a short distance in search of
food. In the case described and discussed in this text, it is being used to discuss a class of
movement where fish return to the region from which they have migrated for various reasons
(Northcote, 1991).
Different factors, or a combination of them, may actually cause the migration of fish. All
aspects will be addressed. These factors include hormonal urges within the fish, light
stimulation, temperature, and their genetic disposition.
Trout have many hormonal urges, which contribute to their migratory behavior.
Hormones can both initiate and control migration. "Internal physiological changes are presumed
to produce a metabolic stress which forces the fish to move into different waters" (Hoar, 1953).
Hormones released from the pituitary and thyroid glands cause internal sexual stimuli, which can
initiate migration by causing the maturation of the gonads. They can also cause the stimulation
of the movement itself. Craig-Bennett, (1931) and Fontaine & Koch, (1950) found that both
pituitary injections and increased thyroid activity stimulated fish to mature and, in tum, move.
Hoar et aI, (1953) also found that male hormone increases the rate of metabolism and speed of
swimming fish. Both gonadic and thyroid hormones are active during upstream migration, affect
the activity of fish, and may be a source of activation of the nervous center. These hormones set
off the appetitive behavior of the spawning migration (Hoar, 1953). Hormonal changes are a
biological stimuli for trout to gather at the mouth of the river system from where they swam as
juveniles (Northcote, 1991). The ripening of the gonads provides the primary impetus for the
fall migration of trout into tributaries to spawn. Stuart (1953) explained that this internal
stimulus is apparently indispensable because there are no reports of immature or non-ripening
fish entering spawning tributaries in the fall of the year. Many adult fish fail to ripen each year,
but these fish will then remain in the main river without traveling into tributaries.
Light stimulation also affects the migration of trout. Photo-periods are lengths of time
that a fish is exposed to light in its habitat. Changes in photo-periods, or even the intensity of the
light, can directly or indirectly affect the migration. The intensity of the light a fish is exposed to
changes over the course of a day or year. Either will affect the fish. "The dynamics of the light
13
intensity throughout the year detennines the course of the maturity cycle in fish to a considerable
extent. Fishes of temperate latitudes reproduce only at particular times of the year" (Nikolsky,
1963). Light exerts a definite influence on the course of the fish's metabolism and also on the
maturation of its gonads. A fish exposed to intense light for a significant amount of time will
mature faster than one that is not.
The process of homing by fish is not fully understood, and has many different
definitions. As related to this research, homing refers to the choice a fish makes to return to the
spawning ground used by its parents rather than any other equally probable place (Gerking,
1959). Usually, this is a considerable distance for the fish. Homing is a very important part of
population stabilization. It can be caused by unfavorable conditions or by spawning
requirements (Gerking, 1959).
A study done in Scotland by Stuart (1975) on both young and adult brown trout proved
that homing occurred. The young occupied five tributary systems and all migrated to the
Dunalastair Reservoir just before the adult spawning run. The spawning run begins in October,
and the younger fish returned to the streams in May. The adult fish returned to the reservoir in
October and November. Furthennore, homing was supported by the fact that at the mouth of one
of the creeks, at a confluence with a second, a small waterfall blocked one passage. The fish,
previously marked upstream of the barrier, chose the more difficult route over the unblocked,
easier pathway. The study continued for three years, with similar results.
As part of the homing process, it is believed that fish use several senses and remember
cues that guide them along their pathways. Northcote (1991) sunnised that trout, specifically,
may recognize currents and hydraulic conditions, which indicate they have been somewhere
before. Trout also use their senses of sight and smell to identify riverbeds and odors of
tributaries to reach their destinations.
Migration of trout can also occur because ofthennal stress. Water temperature increases
over the distance that the water flows. Trout migration is stimulated when water temperatures
became too wann for survival. When found outside of their preferred temperature range, trout
become less efficient at perfonning life functions. Trout will "exhibit high metabolic demands
leading to growth suppression and early mortality if they remain in water temperatures from 17.2
C to 24 C (63 F to 75 F)" (Neilsen and Lisle, 1994). Temperatures above 20 C (68 F) cause trout
to become physiologically stressed, with body functions altered. Because of the wann water
temperatures, the levels of oxygen available to the trout are depleted. Less oxygen causes the
trout to begin to experience respiratory problems. The trout cannot comfortably perfonn bodily
functions, and are forced to respire more often in an attempt to take in the needed levels of
oxygen. They compete less effectively for food and space with better adapted species and are
generally less vigorous and more susceptible to disease and predation (Hokanson et al. 1977;
EPA 1976; and Spotila et al. 1979).
Once trout are stressed from the high water temperatures, they move to areas of cooler
water, known as cool water thennal refuges. Thennal refugia can be spring holes, mouths of
tributaries, or areas where cold water flow releases take place. Most of the trout in this study
that were radio-tagged in the East Branch of the Delaware and the Beaverkill River system
14
moved downstream to locate the cooler water. This occurred because the fish were stressed and
they could not travel long distances against the current. The fish found it easier to locate cooler
water by drifting with the current until an area of suitable temperature and oxygen level was
reached. Based on my data, I theorized that these fish may have grown up in the river, and
allowed the current to take them to the cooler areas because they had migrated from there
previously, and they recognized the area.
Fish growth and populations, including trout, are affected by warm water flows within
the Delaware River tail-waters. Trout populations suffer because of the warm water flows.
When water temperatures in the Delaware River watershed reached 22 to 26 C (72 F to 79 F),
the trout began to move into thermal refugia. Those temperatures exceeding 22 C (70 F) cause
growth rates to slow and juvenile fish to become physically stressed and lose body weight.
Studies indicate that brown trout that are fed at maximum satiation experience their best growth
rates between 14 and 15 C (54 F to 59 F). Their growth rates actually decline in water
temperatures above 18 C (64 F) (Elliot, 1975). Brown trout juveniles lose weight regardless of
how much food they eat when in these higher temperature ranges. Juvenile rainbow trout data
have shown growth rates that are reduced at temperatures exceeding 19 C (65 F) and that
population biomass cannot be maintained when weekly mean water temperatures exceeds 21 C
(70 F) (Hokanson et aI., 1977).
In general, trout located and tagged in the Beaverkill River remained there until water
temperatures became too warm. The fish exited the lower portion of the Beaverkill system in the
late summer. Fish radiotagged in the upper sections, around Roscoe, NY remained there as the
temperatures in this section remain cool enough for year round trout survival.
Trout that were radi-otagged throughout the East branch of the Delaware reacted very
differently than the previously discussed trout. Fish tagged in the upper section remained there
year round, with very little movement tracked. Water temperatures in the area from Harvard,
upstream to the Pepacton dam at Downsville, remained at an almost constant 10 C (50 F)
throughout the spring, summer, and fall months. In the winter, the temperature fell to freezing,
although this is suitable for fish survival. The trout had suitable water flow conditions and
temperatures for survival and growth. Once the water reaches Harvard, it begins to warm
rapidly for two reasons. First, the distance from the dam is considerable, the cool water
discharges not reaching all the way to Harvard. Secondly, the width of the river is a factor
because the wider the riverbed, the shallower it tends to be. This allows the water to warm faster
from the sun. Temperatures below Harvard, down to the confluence of the main Delaware River
at Hancock, often reach stressful temperatures in the summer months. This causes the trout to
seek out the cooler refuge areas at stream mouths, or to exit the system entirely and locate in
another river - usually the West branch of the Delaware. Radio-tagged trout from the lower East
branch showed migratory movement related to the increased water temperatures. Fish tagged
between Harvard and Hancock tended to seek refuge at the confluence pool of the West branch,
or else entered the West branch itself. Some of the fish originating from the East branch swam
upstream to relocate in areas closer to the dam due to the releases from the Pepacton reservoir
throughout the summer months.
15
The main Delaware River, below Hancock, New York, supports a high quality trout
population. Trout located in the Delaware are ultimately dependent on water released from both
its East and West branch tail-waters to survive. Water releases provide the cool temperatures for
trout growth and survival downstream in the main Delaware River. Trout radio-tagged in the
main Delaware River utilized numerous thermal refuges that were previously unknown. One
known thermal refuge is located where the West Branch enters the main Delaware. The trout
congregate there in response to the cold water flows coming out of the West branch. Trout
radio-tagged most often remained stable throughout the entire summer, with no reason to move.
Trout located in the confluence pool all were released and remained on one side of the river in
response to the cold water flows from the West branch. A distinct line could be drawn where the
East and West branches come together, because the water from the West branch is so much
cooler in temperature. It doesn't mix with the warmer flows from the East branch, and creates a
cooler refuge on the Pennsylvania side ofthe river. Trout located in the confluence pool all lie
on that side of the river where the West branch flows are entering.
Other thermal refuges were discovered in the main Delaware River system, often located
at areas where very cold tributaries enter the main river. The cold water flows enabled trout to
congregate at these tributary mouths. Trout further down river, below Hancock, often traveled to
these areas in response to increasing temperatures. The trout also found "spring holes" located in
the main river. These are deep holes where there may have been a spring in the river, causing
the water temperature to be cooler at these points than in the ambient river. The fish spent the
warm summer months in these "spring holes".
Throughout the radiotelemetry study, both hatchery and wild fish were observed
migrating. Both were radi-otagged and observed for movement related to changes in water
temperature. In general, it is believed that hatchery-raised fish move less than their wild
counterparts. They are also thought to be less hardy, and more easily stressed than a wild fish.
Those born and nurtured in the natural stream environment were thought to be better adaptable
and stronger. "Using the scope for activity, which measures the amount of reserve energy
available at a given temperature, Dickson and Kramer in 1971, and Hochachka in 1961 reported
that domesticated hatchery trout have less energy reserved at higher temperatures than do wild
trout" (Behnke, 1991). Secondly, wild trout will move more often than hatchery- raised trout
because of their natural instinct, when they sense a physiological change in their body (Behnke,
1991). Once the fish detects a change in its body in response to the stress of warmer
temperatures, it will seek cooler waters. In this study, 46 trout were of wild origin, and 10 trout
were hatchery raised. Almost half of the fish tagged in the Beaverkill River were of hatchery
origin. From the data collected in 1995, 1996, and 1997, the wild trout in the Beaverkill River
demonstrated greater movement than the hatchery raised trout. Most ofthe hatchery-raised trout
remained in the pool or run where they were captured and tagged, throughout the entire study
period.
As predicted, trout from hatchery origins were more sedentary, as compared to the wild
trout present in the same conditions. Under stressful warm water flow conditions, wild trout
exited the river more often than did the radiotagged hatchery trout present there. All ofthe wild
fish on the Beaverkill in the 1995 study moved out of the river system to seek cooler water.
Previous radiotelemetry studies such as the data collected in 1995 indicated that most hatchery
fish stay in the same general area where they were tagged. One fish tagged in 1995 at the
16
Ferdons pool, just below Roscoe, was a hatchery raised male brown trout. It remained in the
same spot not even moving when it experienced increased water temperatures close to 27 C (80
F), as well as stressful low flow conditions. This fish was thought to have died from the
increase in water temperature. A hatchery raised, female brown trout, also in the Beaverkill in
1995, was radio-tagged in the Cemetery Pool. It did not move at all during the time it was
tracked.
West Branch of Delaware River:
Movement Related to Water Temperature: Data collected from the ten trout radio-tagged
throughout the West branch of the Delaware River indicates that conditions within this system
are suitable for the growth and survival of the trout. Because of the cold water flow releases
within the river system, trout are provided with temperatures rarely exceeding 19 C (65 F), and
adequate oxygen. Three trout, tagged just below the release area of the Cannonsville Reservoir,
acted as a control group. All remained in the area throughout most of the study period. Three
fish dropped downstream to just before the weir dam, after the tagging process. One fish, WB 5­
2, remained there until the late summer or early fall when it was believed to be creeled just
before the closing of trout season in 1996. A second fish, WE 6-2, remained throughout all of
1996 and stayed through early April 1997, when it was caught and creeled by an angler. The
third fish, WE 7-2, was creeled in late August 1996. These fish remained in the area just below
the weir dam because of the cold water release flows from the Cannonsville Reservoir during the
summer months. Other trout radio-tagged farther downstream from the reservoir remained there
throughout the warmer months as well. Water temperatures throughout the length of the West
branch, below the Cannonsville Reservoir, remained suitable for the trout.
Trout radio-tagged at the release dam in Deposit, four miles downstream from Stilesville,
remained here throughout the study period, moving only to spawn. Temperatures at this location
rarely exceed 12 C (55 F), even in the warmest summer months. Two fish tagged in the large
pool below Deposit, in the "no kill" area, remained there during 1996. WE 3-2 is a hatchery­
raised, three-year-old brown trout, and remained stationary in the 1997 study period as well.
WE 4-2, a wild, four-year old brown trout was stationary until June of 1997. It then moved
downstream 14 miles to Balls Eddy. This new location is very popular with anglers, and when
the fish could not be located later, it was assumed that it was creeled and not reported. West
branch fish 8-2 was a wild, 5-year-old brown trout, which was tagged about 12 miles below the
release dam. After tagging, it moved downstream slightly, and then remained just above Balls
Eddy throughout the entire two-year study period.
One fish was tagged 14 miles below the release dam, at Balls Eddy, on the West branch.
This fish did not move at all, except to spawn. It was a 5-year-old wild brown trout, WE 2-2,
and remained in this location because the water temperatures here never exceeded 16 C (60 F)
throughout the summers of 1996 and 1997. Another fish tagged at this location, WE 10-2, was a
4-year-old wild brown trout. It exited the West branch entirely to relocate in the main stem of
the Delaware River 9.66km (six miles) from where it was radio-tagged. It then remained at the
new location throughout the study period, returning to the West branch only to spawn in one of
its tributaries in both 1996 and 1997.
17
Lastly, two rainbow trout tagged in the West branch showed different movement
patterns. A 4-year-old rainbow, WB 1-2, was tagged at Balls Eddy in the early spring of 1996,
and exited the system entirely. This movement, from the West branch to the main stem of the
Delaware, was believed to be due to the time of season that the fish was tagged. It was assumed
that this fish was originally a main stem resident trout, tagged during its migration to spawn.
After the tag was implanted, the fish returned to its residence in the main Delaware River, and
remained there throughout the remaining study period. The second fish, WB 9-2, was a 4-year­
old wild rainbow trout, which was radiotagged in the West branch. The location of the tagging
procedure was 16 km (ten miles) below the release dam in June of 1996. The fish remained
where it was tagged in 1996 and early 1997. The fish moved downstream to a West branch
tributary to spawn, then relocated, and remained at the stream mouth after spawning took place.
Movement Related to Spawning: Brown and rainbow trout located within the West
Branch, either spawn within the West branch, or utilize its tributaries for this purpose. Trout
radio-tagged in the West branch migrated both upstream and downstream to select spawning
sites.
Of the two rainbow trout tagged in the West branch, one spawned in a tributary. WB 9-2,
the 4-year-old, wild rainbow, moved 6.4 km (four miles) downstream from its tagging habitat,
and spawned in Balls Creek, a major tributary to the West Branch. This fish began its journey
downstream in late March of 1997 and then entered the creek. It selected a gravel area and redd
almost immediately. This fish remained in the creek for 20 days, before exiting and relocating
just off of the creek mouth for the remainder of the study period. The second rainbow trout was
the 4-year-old, wild fish tagged WB 1-2. It traveled upstream from the Delaware River system,
and into the West Branch in the spring of 1997. This fish relocated near Balls Eddy on the West
Branch for the entire spawning season, but never entered a tributary. The following chart
summarizes the spawning activity.
Rainbow Trout Spawning Activity in the Spring of 1997 on the West Branch
Date
3/25/97
Tag Frequency(MHz) Fish 10#
52.681
WB9-2
Spawning Location
Balls Creek WBDR
Sex
Time Spent in Tributary (Days)
F
Brown trout radiotagged in the West branch utilized both the main river and its
tributaries for spawning. Of the eight brown trout tagged in the West branch, four of them
utilized some of the tributaries to spawn in the fall of 1996 and of 1997. In the fall of 1996, fish
WB 10-2 and WB 2-2 used these tributaries. WB 10-2 was a wild, 4-year old brown, which
migrated upstream from the main Delaware and spawned in Sands Creek in the lower end of the
West branch. The fish traveled up the creek 3.2km (two miles) and spawned on a gravel area in
the creek bed. WB 10-2 remained in the creek for 6 days before returning to the area where it
was prior to spawning time. Spawning migration ofWB 10-2, lasted about four weeks, with
20
18
migration upstream beginning in late September and the fish entering the creek on October 29th,
1996. WB 10-2 exited Sands Creek on November 4th, 1996 and returned to the Delaware River.
The second brown trout utilizing a tributary of the West branch for spawning was fish
WB 2-2. This was a 5-year old, wild fish. It migrated 402.4m (1/4 mile) upstream from its
tagging location, and spawned in Balls Creek on the West branch. The fish traveled another
402.4m (1/4 mile) up the creek and spawned on a gravel area. The fish entered the creek on
November 12th, 1996 and exited on November 19th, 1996. All other brown trout radiotagged in
1996, showed upstream mi gration to known spawning areas within the West branch of the
Delaware River itself, for the 1996 spawning season.
Fall Brown Trout Activity in the Spring of 1996 on the West Branch
Date
Tag Frequency
Fish 10#
Spawning Location
Time Spent in Tributary(DAYS)
Sex
10/29/96
52.611
WB 10-2
Sands CreekWBDR
M
7
11/12/96
53.681
WB 2-2
Balls CreekWBDR
F
7
Of the eight brown trout radio-tagged in 1996, four remained active tags in the following
year of 1997. Of these four fish able to be tracked again, three of them utilized tributaries of the
West branch for their 1997 spawning. WB 3-2 was a 3-year old hatchery male, which spawned
in Oquaga Creek, below Deposit, NY. It was radio-tagged in the West branch 1.6km (one mile)
below the creek. It began its upstream migration in mid October 1997, and actually entered the
creek on November 3rd , 1997. This fish was observed spawning with a female, and entered the
creek two days later. Another brown trout, WB 8-2 migrated upstream 1.6km (one mile) to
spawn in Roods Creek, another tributary to the West branch. This fish was a wild 5-year-old
male which entered the creek on November 4, 1997, and swam 402.4m (1/4 mile) up the creek
where it was observed on a redd with a female brown. After spawning, it exited the creek on
November 10,1997.
The last brown trout which utilized a tributary to spawn was WB 10-2. This fish, a 4­
year old, wild male, entered the same tributary in 1997 as it did in 1996, and followed almost the
exact spawning migration pattern in both years, except for the timing. This was attributed to the
tributary flow, which was greater in October 1996 than in 1997. WB 10-2 did not enter Sands
Creek until November 25, 1997 after a fairly heavy rainfall. The fish swam upstream to the
exact spawning location as previously, spawned, and then exited one week later. The fish then
relocated to its prior location in the main part of the Delaware River system.
Brown Trout Activity on West Branch in the Fall of 1997
19
Date
Tag Frequency(MHz) Fish ID#
Spawning Location
Sex
Time Spent in Tributary(DAYS)
11/3/97
53.563
WB 3-2
Oquaga CreekWBDR M
2
11/4/97
52.651
WB 8-2
Roods CreekWBDR
M
6
11/25/97
52.611
WB 10-2
Sands CreekWBDR
M
7
Main Delaware River:
Movement Related to Temperature: Data collected from radio-tagged brown and
rainbow trout in the main Delaware River indicates that the trout are ultimately dependent upon
cold water releases from the West branch for growth and survival. Trout in the system migrate
to thermal refuge areas. When water temperatures become too warm, these trout become
physiologically stressed.
Radio-tagged rainbow and brown trout moved both upstream and downstream to locate
thermal refuge areas. Once ambient river temperatures reached 22 C (70 F) or above, fish
searched out areas of cooler water. Rainbow trout seemed to react quicker than brown trout to
warming water temperatures. The rainbows seemed to have moved further in a shorter time
period than the browns, whether up or downstream.
DR 1-2, a 3-year-old wild rainbow trout, was tagged about l2.9km (8 miles) below
Hancock, NY at the Buckingham access site. It showed movement from there in mid June of
1996, when water temperatures reached 19 C (66 F). DR 1-2 traveled 9.66 km (six miles) and
relocated at a thermal refuge off of the mouth of the Bouchouville Brook. This fish remained
there throughout the summer of 1996 while water temperatures remained a nearly constant 16 C
(60 F). Moving upstream only to spawn, DR 1-2 followed almost the same pattern in 1997,
relocating to the refuge area in mid June to spend the entire summer, fall and winter there.
DR 2-2, a 3-year-old wild rainbow trout, was also tagged at the Buckingham access. It
moved downstream in the summer of 1996 when the water temperatures approached 21 C (70
F) at the tagging location. This fish moved close to 64.4 km (40 miles) downstream in late June
of 1996, to relocate near a spring hole present off of the mouth of Ten Mile Creek, below
Narrowsburg, NY. DR 2-2 remained there all summer until starting a migration back upstream
in late September when the river temperatures cooled in the fall. The fish then wintered at the
area where it was tagged, and in the spring migrated upstream to a gravel bar in the main
Delaware below Hancock, NY to spawn. Subsequently it moved back downstream. The fish
spent the summer of 1997 and the rest of the study period, 1.6 km (one mile) upstream from its
tagging location. The water temperatures never exceeded 18 C (65 F) there because of cold
water releases.
20
DR 3-2 was a 5~year-01d hatchery-raised brown trout, which was also tagged at
Buckingham access. This fish moved constantly upstream during the summer of 1996. It spent
most of the summer off of the mouth of Read Creek on the East branch of the Delaware. Local
water temperatures never exceeded 20 C (68 F). DR 3-2 moved back downstream in the fall to
its original position. After spending the fall and winter at the Buckingham access, the fish
moved in mid June 1997 to a large known thermal refuge pool at the Junction Pool of the East
and West branches in Hancock. DR 3-2 located there, on the coldwater side where the cool west
branch release waters enter the Delaware River. The fish remained there throughout the rest of
the study period.
The last fish tagged at Buckingham access was DR 4-2. This fish was a four-year-old,
wild rainbow trout. It moved downstream in early summer of 1996, traveling 9.66 km (six
miles) to locate off the mouth of Abe Lord Creek below Lordville, NY. Water temperatures
never exceeded 19 C (66 F) during the summer. DR 4-2 remained through the fall, winter, and
early spring 1997. It then moved upstream in late spring of 1997 to spawn in the East branch
tributary, then relocated back to the tagging location at Buckingham to spend the summer of
1997. Water temperatures there stayed a constant 17 C (64 F).
A 5-year-old wild brown trout, DR 5-2, was tagged at Lordville, NY. It moved upstream
3.2 km (two miles) when water temperatures reached 25 C (76 F) in July of 1996. This fish
relocated the 3.2 km (two miles) to the mouth of Equinunk Creek where flows entering the river
are at a constant temperature of 18 C (65 F) throughout the summer months. DR 5-2 then
returned to Lordville, NY to its tagging location. The fish remained throughout 1996 and most
of the 1997 study period, until the tag was recovered along the bank in August of 1997.
A wild rainbow trout tagged at Lordville, NY moved upstream in the early summer of
1996 and spent the summer months near the mouth of Equinunk Creek, where water
temperatures never exceed 18 C (65 F). This fish was never documented again after August
1996, and it is thought that the fish was creeled because the tag was never located after scanning
the entire watershed area.
Another 4-year-01d, wild rainbow, tagged .8 km (one- half mile) below Lordville, NY,
moved downstream 4.03 km (2.5 miles) in the early summer of 1996 when the water
temperatures at Lordville reached a stressful 22 C (72 F). DR 9-2 relocated to a thermal refuge
downstream, near the mouth of Bouchouville Brook. This fish spent the entire fall and winter
there as well, moving upstream to spawn in a main stem tributary, and then returning to the same
location in 1997. The fish remained there through the summer, fall, and early winter when the
study period ended in December of 1997.
DR 10-2 was a four-year-01d wild brown trout, tagged .8 km (one-half mile) below
Lordville, NY in the early spring of 1996. In the first part of June, the water temperatures
approached 21 C(70 F), and DR 10-2 started moving upstream and reached Hancock by mid
June. On June 25, 1996, the fish entered the West branch where water temperatures were cooler.
It then swam up the length of the West branch to the large poo110cated just below Deposit, NY.
It spent the summer months there, until late September, when it returned to the tagging location
21
in early October. DR 10-2 followed the same pattern in 1997, relocating in the West branch
around the Balls Eddy area until late September and then returned to the tagging location.
DR 11-2 was a wild, 5-year-01d rainbow tagged at Long Eddy, NY in early March 1996.
Soon after tagging, DR 11-2 moved 16.1 km (10 miles) upstream to an area near Lordville,
where it was documented in late April. The fish remained there until late June, when water
temperatures approached 24 C (74 F). It then quickly moved 37 km (23 miles) upstream, in 8
days, to relocate in the large pool below Deposit, NY. This pool is in the West branch and the
water temperature was 11 C (54 F). DR 11-2 spent the summer months there, and remained
through the fall and winter of 1997. In the spring of 1997, the fish moved downstream to spawn,
returning to the pool and remaining there through the end of the study period.
A 5-year-01d, hatchery-raised brown trout, DR 14-2, was tagged 3.2 km (2 miles)
upstream of the Buckingham access in late May of 1996. The fish moved upstream in late
August of 1996, in response to river temperatures of 22 C (70 F). It relocated to a riffle below
Hancock, NY where the water temperature was 12 C (62 F) in response to West branch release
flows. This fish spawned in an East branch tributary in October of 1996 and then could not be
located after that. An angler in the vicinity of the area where DR 14-2 was originally tagged
recovered the radio-tag.
DR 15-2, a wild, 4-year-old brown trout, was radio-tagged 3.2 km (2 miles) above the
access site at Buckingham. During the summer of 1996, this fish traveled upstream to the
junction pool in Hancock. The water temperature was 16 C (60 F) throughout the summer
months. The same pattern was followed in 1997 by DR 15-2, with the fish traveling from
Buckingham to the refuge located on the side of the river where the West branch enters the river.
Another fish tagged at this same area above Buckingham, DR 16-2, was a wild, 4-year­
old male brown trout. The temperature in the Delaware River at the tagging location was 21 C
(69 F). This fish traveled upstream during the summer of 1996 to Hale Eddy, NY located on the
West branch of the Delaware, where water temperatures were a cold 14 C (56 F) throughout the
entire system. DR 16-2 spent the summer months in the West branch, moved back to its tagging
location in the late fall, and in the following summer months of 1997, migrated back upstream to
the large thermal refuge in the junction pool of the Delaware river below Hancock.
DR {7-2 was a wild', rain60w tagged .[5 KIn (one-ha((mde) 6e(ow the guckingham
access. It never showed any movement at all during the two year study period. Numerous
attempts were made at trying to move the fish by wading into the river and locating it. The fish
was not found. It could have died from complications resulting from the surgery, and the tag
was never recovered. Temperatures in this area often reached stressful temperatures of near 24
C (73 F) during the summers of 1996 and 1997, with no reaction from this fish.
A 3-year-old, hatchery- raised female brown trout was tagged below Hancock, NY in
June of 1996. DR 18-2 never moved out of its tagging location, except to spawn, because
temperatures never reached above 18 C (65 F). This fish was radio-tagged close to the known
thermal refuge located where the cold water releases from the West branch enter the system. DR
22
19-2, a wild rainbow tagged in this same area responded in the same manner, moving only to
spawn.
DR 20-2 was a wild, 4-year-01d rainbow trout tagged at Lordville, NY. This fish stayed
close to the area of spawning, moving downstream about .8 kIn (one-half mile) to the mouth of a
small brook, called Abe Lord Brook, in the summer months. Temperatures at its tagging location
reached 24 C (74 F), while at Abe Lord Brook, temperatures were a cooler 16 C (61 F). This
same migratory pattern was followed in the summer of 1997 as had been in 1996.
The final fish radio-tagged in the Delaware River, DR 21-2, was a wild, 4- year-old
brown trout, which was tagged .8 kIn (one-half mile) below Buckingham access site in June of
1996. Soon after tagging, the river temperatures reached near 21 C (70 F), forcing DR 21-2 to
migrate to cooler water. It traveled nearly 16 kIn (ten miles) upstream to the large thermal
refuge located at the junction pool below Hancock. It spent the summer there and moved back
downstream in the fall. DR 21-2 spent the winter and spring below Lordville. In the summer of
1997, the water temperatures at Lordville were near 21 C (70 F), and DR 21-2 migrated
downstream to cooler water off of Bouchouville Creek mouth, and spent the remainder of the
study period there.
Movement related to Spawning: Both brown trout and rainbow trout in the Delaware
River system spawn in the main river or utilize the tributaries of the West, East, or main
Delaware rivers itself in which to spawn. Trout radio-tagged in the Delaware River system
often traveled great distances of up to 48.3 km (30 miles) to enter tributaries to spawn.
In the spring of 1996, five out of seven rainbows tagged before spawning utilized
tributaries for their spawning activities. Tributaries of the East branch, West branch, and main
Delaware River were all used by rainbows in spawning in 1996.
Rainbow Trout Activity in the Spring of 1996 on the Main
Delaware
Data
Tag Frequency(MHz) Fish ID#
Spawning Location
Sex
Time Spent in Tributary(DAYS)
3/31/96
52.571
DR 9-2
Abe Lord CreekDR
F
8
4/2/96
52.382
DR 1-2
Balls CreekWBDR
F
6
4/5/96
52.641
DR 8-2
Shehaw CreekWBDR F
14
4/29/96
52.551
DR4-2
Read CreekEBDR
F
12
6/28/96
52.54
DR 2-2
Callicoon CreekDR
F
14
23
Of the ten rainbows radio-tagged in 1996, six utilized tributaries for spawning in 1997.
Out of these six fish, three of them; DR 9-2, DR 1-2, and DR 4-2 returned to the same tributaries
that they used in 1996. During the springtime, other rainbows tagged in the Delaware River did
show migratory movement, toward areas of spawning gravel which were located in the main
Delaware system.
Rainbow Trout Spawning Activity on the Main Delaware in theSpring of
1997
Data
Tag Frequency(MHz) Fish ID#
Spawning Location
Sex
Time Spent in Tributary(DAYS)
3/31/97
52.571
DR 9-2
Abe Lord CreekDR
F
8
4/1/97
52.622
DR 11-2
Balls CreekWBDR
F
6
4/1/97
52.382
DR 1-2
Balls CreekWBDR
F
6
4/1/97
52.752
DR 20-2
Abe Lord CreekDR
F
7
4/21/97
52.561
DR 19-2
Read CreekEBDR
F
7
5/6/97
52.551
DR4-2
Read CreekEBDR
F
14
Eleven brown trout were radiotagged in the Delaware River in 1996. Five ofthese fish
utilized the tributaries to spawn in during the fall of 1996. Tributaries of the East branch, West
branch, and Delaware River were all used for brown trout spawning in 1996.
Brown Trout Activity on the Main Delaware in the Fall of 1996
Date
Tag Frequency(MHz) Fish ID#
Spawning Location
Sex
Time Spent in Tributary(DAYS)
10/22/96
52.72
DR 14-2
Cadosia CreekEBDR F
14
10/23/96
53.611
DR 16-2
Sands CreekWBDR
M
10
10/28/96
52.601
DR 10-2
Abe Lord CreekDR
M
14
10/29/96
52.711
DR 18-2
Oquaga CreekWBDR F
6
11/11/96
53.6
DR 15-2
Shehaw CreekWBDR F
32
24
In the fall of 1997, three Main Delaware River fish used tributaries for spawning. DR
10-2, DR 15-2, and DR 16-2 used the same tributaries in 1997 where they had spawned in the
fall of 1996. Spawning in 1997 was almost a month later due to low water conditions, which
lasted until late October. Then, heavy rains brought the stream flows back up, allowing the fish
to enter the tributaries. The length of stay in the tributaries varied from days to months. Other
brown trout in the Delaware River utilized the main Delaware for spawning activity, and began
to show movements towards their spawning locations at the predicted time.
Brown Trout Activity on the Main Delaware in the Fall of 1997
Date
Tag Frequency(MHz) Fish ID#
Spawning Location
Sex
Time Spent in Tributary(DAYS)
11/24/97
52.601
DR 10-2
Abe LordCreekDR
M
7
11/25/97
53.6
DR 15-2
Shehaw CreekWBDR F
30
11/25/97
53.611
DR 16-2
Sands CreekWBDR
32
M
Four fish radio-tagged in 1996 in the main Delaware River system were also creeled in
1996. Of these four tags, two were re-implanted into different fish in the system. The fish
creeled in 1996 were all caught within three months of tagging. DR 6-2, DR 8-2, DR 12-2, and
DR 14-2 were all creeled in early summer 1996.
East Branch Delaware River:
Movement Related to Temperature: Both brown and rainbow trout radio-tagged in the
East Branch of the Delaware River in 1996 showed migratory movements towards areas of
cooler water in the warm summer months. These were located in the East branch itself, or they
moved all the way out of the East branch and into the large refugia located where the West
branch empties into the main Delaware river at Hancock, NY. Fish radiotagged close to the dam
at Downsville, and just downstream, remained throughout the entire year, moving only to spawn.
Water temperatures in this region are a near constant 10 C (50 F), which is related to the 90 cfs
release flows from the Pepacton Reservoir.
EB 1-2, a wild, four-year-old female brown trout, was tagged 3.2 km (two miles) below
the Pepacton release dam. She never moved from the tagging location except to spawn. Water
temperatures there remained at near 12 C (52 F) throughout the summers of 1996 and 1997.
EB 2-2, a five-year-old, wild brown trout was tagged 1.6 km (one mile) below Harvard,
NY. Water temperatures here vary, often reaching 21 C (68 F) during the summer months,
because the river is quite wide and shallow at this point. River widths average 30.5 m (100 feet),
and depths average 25.4 em (10 inches). EB 2-2 swam upstream in early summer 1996, toward
25
the release dam, and relocated there for two weeks near Shinhopple which is 8 km (5 miles)
above the release dam. EB 2-2 slowly worked its way back downstream by midsummer and
relocated once again to below Harvard at a large known thermal refuge. This refuge is located in
a large deep pool, fed with multiple cold water springs.
Another fish, tagged 1.6 km (one mile) below Harvard, NY, was EB 3-2. This rainbow
trout relocated to the known thermal refuge just upstream from its tagging location, and spent the
entire summer, fall, and winter of 1996 here. EB 3-2 was then creeled in the early summer on
June 9, 1997.
A fish tagged in the lower East branch, EB 4-2, was a wild, four-year-old brown trout.
Its tagging location was 8 km (five miles) above Hancock, NY. This fish migrated upstream in
the summer of 1996. Water temperatures in the lower East branch often reach near 23 C (70 F)
in summer months. By late June 1996, water temperatures had reached 25 C (72 F) at the
tagging location ofEB 4-2. This fish migrated upstream nearly 32.2 km (20 miles) to relocate at
the cold water refuge area just below Harvard, NY where water temperatures were a cool 15
C(60 F). EB 4-2 spent the summer months in the refuge until late September. At this time, EB
4-2 disappeared. The fish could have been creeled and not reported. The radiotag was never
recovered.
EB 5-2 was a three-year-old, wild brown trout tagged in the lower East branch around
Peas Eddy. This fish exited the entire East branch system in the summer of 1996 in response to
the warm water temperatures. EB 5-2 swam 8 km (five miles) downstream to the Junction Pool
in Hancock, then entered the cooler West branch water, swimming the entire length of the West
branch to relocate in the 12 C (54 F) waters below Deposit, NY. This fish slowly moved back
downstream throughout the summer months, but stayed solely in the West branch of the
Delaware. EB 5-2 spawned in a West branch tributary in the fall of 1996, and was assumed to
have perished there. The tag was never recovered.
Another radio-tagged fish in the East branch, EB 6-2 was a three-year-old female
hatchery raised brown trout tagged about 1.6 km (1 mile) above Hancock, NY. This fish
remained in its tagging location until early July of 1996. When the water temperatures rose to
25 C (72 F), it moved about 16 km (ten miles) upstream to just above the bridge at Fish's Eddy.
Water temperatures here were 20 C (68 F). EB 6-2 remained there throughout the rest of 1996
and the early spring of 1997. In late June, 1997, the temperatures reached 26 C (74 F) and EB
6-2 moved back downstream. Leaving the East branch entirely, the fish located in a thermal
refuge area on the West branch side of the Junction pool near Hancock.
EB 7-2 was a four-year-old, wild brown trout tagged in the same location, 1.6 km (one
mile) above Hancock. It followed a similar migratory pattern to EB 6-2. EB 7-2 moved
downstream to Hancock in the summer months of 1996, then relocated back to its tagging
location for the fall, winter and early spring of 1997. When stressful thermal conditions
occurred once again in the summer months, it returned to the thermal refuge at the Junction Pool
near Hancock in the Delaware River.
26
East branch fish EB 8-2, a four-year-old wild brown trout, was radio-tagged 9.66 Ian (six
miles) below the release dam in Downsville. Water temperatures at the tagging location never
exceeded 17 C (60 F) throughout the entire two year study period. EB 8-2 responded by never
moving from the tagging location, except to spawn 1.6 km (one mile) upstream. EB 9-2
followed the same pattern. This fish was a wild brown trout tagged about 6.4 Ian (four miles)
below the Downsville release dam, and moved only to spawn.
EB 10-2 was a wild, five-year-old brown trout. This fish was tagged just above Harvard,
NY. EB 10-2 spent the summer of 1996 at the tagging location where the water temperatures
never exceeded 17 C (64 F). EB 10-2 then moved 40 Ian (25 miles) downstream, to spawn in a
tributary of the Main Delaware. This fish also utilized another large thermal refuge at the mouth
of Bouchouville Brook in the summer of 1997. Temperatures of the water in the pool were a
cool 15 C (60 F). EB 10-2 remained here throughout the rest of the study period.
EB 11-2 was also radio-tagged in the cooler waters of the upper East branch. This three­
year-old brown trout was a hatchery raised female, tagged about 12.8 Ian (eight miles) from the
release dam at Downsville. EB 11-2 moved upstream to reach 12 C (55 F) water throughout the
summer of 1996. This fish spent the summer, fall, winter, and early spring 1997 there, until it
was creeled in early June of 1997. EB 12-2 was radio-tagged at the junction of the Beaverkill
and the East branch in late May of 1996. It swam upstream in the East branch directly to the
dam in Downsville, and was creeled there in the middle of June, 1996.
A four-year-old, wild brown trout was tagged in late May of 1996 and identified as EB
13-2. This fish was radio-tagged in the large riffle of the lower East branch just below where the
Beaverkill enters the river. EB 13-2 remained at the tagging location until mid June of 1996.
Water temperatures reached 22 C (70 F). EB 13-2 then migrated downstream 1.6 km (one mile)
until finding a spring hole in the East branch just below the Shad Pool. EB 13-2 relocated there,
where water temperatures remained a near constant 15 C (60 F) throughout most of the summer
and fall. In late fall, this fish moved back to its tagging location, which could have been its
spawning migration. EB 13-2 spent the fall, winter, and spring in the same location. In 1997,
the fish then dropped back downstream to the same location as 1996 until late July. This was the
last documentation on the position ofEB 13-2 and it was assumed that the fish was creeled and
never reported as the radio-tag was never recovered.
Another fish tagged in this same location, just below the confluence of the
Beaverkill, was EB 14-2. This was a wild, three-year-old rainbow trout. After tagging, this fish
immediately swam upstream into the Beaverkill4.8 Ian (three miles) to Pork Eddy and stayed
there all summer in a large deep pool in 18 C (64 F) water. EB 14-2 moved back downstream to
spawn in an East branch tributary the following spring. Soon after spawning, the fish relocated
to the same location in the Beaverkill until the water temperatures there reached 23 C (74 F) in
early June 1997. EB 14-2 next moved 38.4 Ian (24 miles) downstream, exited the East branch
system entirely and relocated in the large thermal refuge at the Junction Pool in the Delaware
below Hancock. EB 15-2 was tagged in the same location, and was a wild, four-year-old
rainbow. This fish remained stable through the summer months until late August of 1996.
Temperatures then reached 23 C (75 F) on hot, sunny days. EB 15-2 could not be documented
after this time, and was thought to have been creeled, or the radio-tag malfunctioned.
27
East branch rainbow trout EB 16-2, a wild, three-year-01d female, was tagged in the riffle
of the East branch just below the confluence of the Beaverkill River. This fish moved into the
cooler waters of the upper East branch in the summer of 1996, and in the summer of 1997 swam
40 km (25 miles) downstream to utilize the large thermal refuge area below Hancock on the
West branch side of the river.
Another fish tagged at this location, EB 17-2 exited the East branch entirely in the
summer of 1996 and entered the cold water flows of the West branch. The fish swam all the way
up the West branch to the "no kill" area located just below Deposit, NY and remained there
throughout the rest of the study period.
The last fish radio-tagged in the East branch, EB 20-2, was four-year-01d, wild
rainbow trout tagged 1.6km (one mile) above Fish's Eddy. Soon after tagging, it went
downstream to Peas Eddy, which is 8 km (five miles) above Hancock. EB 20-2 remained there
all winter, and migrated back upstream to spawn in an East branch tributary near to where it was
tagged. After spawning, EB 20-2 returned downstream to Peas Eddy, until the water
temperatures there reached 26 C (77 F) in early June of 1997. It then exited the East branch and
spent the rest of the summer below Hancock in the large thermal refuge in the Delaware River
on the West branch side.
Movement Related to Spawning: Brown and rainbow trout radio-tagged in the East branch of
the Delaware River migrated to spawning locations within the river system, or utilized tributaries
of the East branch to spawn in. There were two exceptions; one brown, radio-tagged in 1996,
spawned in the fall in Little Equinunk Creek, which is a tributary to the Main Delaware River.
Another brown trout, tagged in 1996, spawned in the fall of 1996 in Shehawken Creek, which is
a tributary of the West branch of the Delaware River.
In the fall of 1996, six of the twelve brown trout tagged spawned in tributaries.
Of the other five brown trout that were active in the fall of 1996, all showed migratory
movement during late October through December to spawning areas in the East branch. In the
fall of 1997, only one brown trout, EB 1-2 utilized a tributary. This was the same tributary that it
used in 1996, Trout Brook. This fish actually used the same gravel area in the stream for
spawning both years.
Brown trout, which spawned in tributaries in the fall of 1996, stayed in the tributaries for
varying lengths oftime. EB 1-2 spent only six days in Trout Brook, while another brown trout,
EB 5-2, never exited Shehawken Creek after spawning there in late October. Generally, in 1996,
brown trout remained in the tributaries six to fourteen days before they exited and headed back
to the river.
Brown Trout Activity on the East Branch in the Fall of 1996
Date
Tag Frequency(MHz) Fish ID#
Spawning Location
Sex
Time Spent in Tributary(DAYS)
28
10/1/96
53.802
EB 10-2
Little EquinunkDR
M
15
10/21/96
53.631
EB 11-2
Trout BrookEBDR
F
6
10/23/96
53.66
EB 5-2
Shehaw CreekWBDR M
10/28/96
53.671
EB 1-2
Trout BrookEBDR
F
6
10/28/96
53.572
EB 2-2
Harvard BrookEBDR
M
14
11/11/96
52.772
EB 7-2
Cadosia CreekEBDR M
7
unknown
Brown Trout Activity on the East Branch in the Fall of 1997
Date
Tag Frequency(MHz) Fish ID#
11/25/97
53.671
EB 1-2
Spawning Location
Time Spent in Tributary(DAYS)
Sex
F
Trout BrookEBDR
14
Six rainbow trout were radio-tagged in the East branch in 1996. None of these fish
migrated to tributaries to spawn. This was most likely due to the fact that most of the tags were
implanted following the spring spawning season. In the spring of 1997, four of the six rainbows
spawned in tributaries. All of the fish used tributaries in the East branch for spawning. EB 3-2
spawned in Morrison Brook below Harvard, and EB 14-2, EB 16-2, and EB 18-2 all spawned in
Read Creek between Fish's Eddy and East Branch, NY. Length of stay in the streams varied
from six to ten days. Rainbows migrated both upstream and downstream to select spawning
sites, and entered tributaries from late March through the end of April.
Rainbow Trout Activity on the East Branch in the Spring of 1997
Date
Tag Frequency(MHz) Fish ID#
Spawning Location
Time Spent in Tributary(DAYS)
Sex
3/25/97
52.671
EB 3-2
Morrison BrookEBDR
F
10
4/21/97
52.742
EB 18-2
ReadCreekEBDR
F
6
4/21/97
53.651
EB 16-2
ReadCreekEBDR
F
7
4/22/97
52.522
EB 14-2
ReadCreekEBDR
F
6
29
Beaverkill River:
Movement Related to Temperature: Both rainbow and brown trout were radio-tagged in
the Beaverkill River in 1996. Only one rainbow trout was radio-tagged in the Beaverkill River
tagged just below Pork Eddy on the lower Beaverkill. This sole rainbow, BK 6-2, was released
after the surgery, never be documented again. It is assumed that the radio-= tag malfunctioned.
Brown trout tagged in the Beaverkill showed migratory movements toward cold water
areas in the warm summer months when the water in its lower reaches often reach near 27 C (80
F) in the summer months. The width of the stream, and its shallow streambed characteristics help
account for this high temperature. Trout tagged here exited the system to seek cold water
thermal refuges elsewhere.
BK 1-2 was a wild, three-year-old female, brown trout tagged about 4.8 km (three miles)
downstream of Roscoe, NY. This fish moved further downstream in early summer of 1996, to a
deep pool in Cooks Falls, NY. In late June, this fish could no longer be documented. BK 1-2
was believed to have been creeled and never reported. The area where the fish was located is a
very popular with local anglers in the community.
Beaverkill radio-tagged brown trout BK 2-2, a five year old wild female was tagged in
the world famous Cairns Pool, one of the two "no kill" sections present on the Beaverkill River
system. Temperatures there reached 22 C (70 F) by late June 1996, and BK 2-2 migrated
upstream to the Junction Pool in Roscoe, NY. The Upper Beaverkill and the Willowemoc Creek
come together at this junction pool. This area is a cold water refuge, and BK 2-2 spent the entire
summer in the large deep pool. After spawning in the fall, the fish returned to their tagging
locations for the winter and spring, and then followed the same migratory patterns in the summer
of 1997.
BK 3-2, a five year old, wild, male brown trout, was tagged in the lower Beaverkill in
Cemetery Pool, about 1.6 km (one mile) upstream of Horton, NY. Stressful water temperatures
of near 23 C (75 F) in both the summers of 1996 and 1997, forced BK 3-2 to seek cooler water
present at the mouth of Horton Brook, downstream of the tagging location. This is a large, well
known thermal refuge area, where many trout congregated in warm summer months. Water
temperatures coming out of Horton Brook, are often up to 9 C (15 F) cooler than ambient river
temperatures, creating a known thermal refuge area in the summer.
BK 4-2, a three-year-old, hatchery raised, brown trout, was tagged about 3.2 km (two
miles) downstream of Horton, NY in late May of 1996. Two weeks after tagging, BK 4-2
disappeared. If this fish were creeled, it was never reported.
A four-year-old hatchery brown trout, BK 5-2, was tagged on the lower Beaverkill in
Horton, NY. It remained there for a couple of weeks after tagging in late May of 1996. After
temperatures in late June of 1996 reached 23 C (70 F), BK 5-2 started to migrate upstream
toward Roscoe, NY, moving constantly upstream throughout the Beaverkill River during the
summer of 1996. By late July of 1996, BK 5-2 was 4.8 km (three miles) above Roscoe, NY in
the cold 16 C (60 F) waters of the upper Beaverkill River, where it remained until late
30
September. It migrated back downstream to Mountain Pool near Cooks Falls, NY. Water
temperatures there were cooling rapidly through the fall season. BK 5-2 remained there over a
spring hole, for the entire 1997 study period, and never moved. Water temperatures at Mountain
Pool, ranged from 14 to 16 C (58 to 60 F).
Another brown trout, a four-year-old hatchery fish, BK 7-2 was tagged about 6.4 km
(four miles) below Horton, NY on the lower Beaverkil1. This fish moved 1.6 km (one mile)
upstream to cooler water near Horton. Water temperatures at the tagging location reached 23 C
(72 F) in the summer of 1996, and BK 7-2 moved to an area where temperatures were near 20 C
(68 F), and stayed there. The fish spawned in a Beaverkill tributary in the fall of 1996, and
could not be documented after that time.
Movement Related to Spawning: Brown trout utilized tributaries of both the Beaverkill River,
and Willowemoc Creek to spawn in the fall of 1996. BK 3-2, and BK 7-2 utilized Horton Brook
on the lower Beaverkill to spawn in 1996. BK 2-2 migrated from Junction Pool in Roscoe, NY
upstream into the Willowemoc Creek, and onward into Stewart Brook to spawn.
Brown Trout Spawning Activity on the Beaverkill in the Fall of
1996
Date
Tag Frequency(MHz) Fish ID#
Spawning Location
Sex
Time Spent in Tributary(DAYS)
9/30/96
52.792
BK 3-2
Horton BrookBK
M
98
10/21/96
53.642
BK 2-2
Stewart BrookWC
F
7
12/24/96
53.771
BK 7-2
Horton BrookBK
F
unknown
In the fall of 1997, only BK 3-2 utilized a tributary, Horton Brook, to spawn. This was
the same behavior as in the fall of 1996.
Brown Trout Activity on the Beaverkill in the Fall of 1997
Date
Tag Frequency(MHz) Fish ID#
10/13/97
52.792
BK 3-2
Spawning Location
Sex
Horton BrookBK
M
Time Spent in Tributary(DAYS)
8
8
31
Most fish that spawned in the Beaverkill system migrated upstream to either a tributary
or a gravel area located in the main river system there. Most did so in a short time, usually one
week, while BK 3-2 in 1996 spent a month in the creek before exiting back to the river to spend
the winter.
CONCLUSIONS
Trout are migratory in the Delaware River and its East and West branches, as well as the
Beaverkill River. Migratory movements, due to stress caused by low warm water flows and
spawning, force trout to move. Migratory movement prior to spawning was noticed in both
species. Some ofthe fish in the Delaware River system moved upstream, while others moved
downstream. Most ofthe fish radiotagged in this study showed some type of post spawning
movement as well. Once the fish had spawned, they would either stay near the spawning area, or
immediately return to the place that they occupied before the spawning migration occurred.
Movement also occurred after the tag was implanted. Most fish either moved upstream
or downstream soon after the surgery. This can be attributed to many factors, including the
lingering effects of the anesthesia on the fish's' balance and equilibrium, and the weight of the
tag in the body cavity. Most ofthis movement, which took place after the tagging, ranged from
183 m-457 m (200-500 yards) from the tagging site.
Brown trout in the radio-tagging project utilized both of the main rivers to spawn, as well
as the tributaries. The trout spawned in the tributaries of the East branch, West branch,
Beaverkill, and the main Delaware River stem. The changing photoperiods, or the length of
daylight, influenced the pre-spawning movements ofthese brown trout. In the fall the shorter
days stimulate brown trout to migrate to spawn (Arnold et al. 1987). This movement generally
begins in late September, with peak spawning periods from late October through late November.
Fish generally moved upstream to spawn in the fall, and then remained in their spawning
locations for a period of time. The period ranged from 7 days to 4 months. One brown trout,
BK 3-2 remained in the spawning tributary until mid winter, when it then exited the tributary and
swam downstream. Meyers et al. (1992) explains that post -spawning brown trout often make
long, rapid movements downstream directly following their spawning activity.
Brown trout radio-tagged in this study also showed homing movements during spawning
activity. Four brown trout tagged in 1996 spawned in tributaries and these same four fish
utilized the same locations in 1997. It is possible that these fish were natives to these streams,
and then naturally returned there as adults to have their young. Arnold et al. (1987) explains that
brown trout "home with an astonishing precision" and can distinguish exact stream locations
and return to them year after year. Brown trout in this study exhibited homing in the main
Delaware River, the Beaverkill, and both the East and West branches ofthe Delaware. All ofthe
fish that showed homing instincts in the radiotelemetry study were wild fish, which is consistent
with other studies, and what one would expect. Hatchery-raised fish should not have had these
tendencies, and those tagged did not. Stuart (1957) and Tilzey (1977) explain that brown trout
32
populations in both lentic and lotic environments (Wetzel, 1983) exhibit homing behavior into
spawning tributaries from its main stem stream. Lentic environments are those in which the
waters stand still, and lotic environments are those in which the water is constant movement
(Wetzel, 1983). In a population, like the one in the Delaware River, wild fish born in tributaries
of the main river are subsequently raised in the system. They become acclimated to their
surroundings, and when they become adults, they return to their natal stream to produce their
offspring.
Rainbow trout radio-tagged in this study showed migratory movements as well. Those
tagged throughout the entire Delaware River system migrated to cool water locations, whether
upstream or downstream. Locations of cooler water, thermal refuges, were found at tributary
mouths, deep pools in the system, and also spring holes located in the Delaware waters. Refuges
were also found where the West branch releases cold water throughout the summer months.
Many rainbow trout moved downstream from the East branch of the Delaware River, and the
Beaverkill to locate at the large thermal refuge located below Hancock. Many of these fish were
hatched as young in tributaries, then were raised in the Delaware River. As young adults, they
migrated upstream into both the upper and lower East branch to continue their growth and
maturity. It is during this stage, that these fish become accustomed to the cold water summer
releases from the Delaware's West branch. When water temperatures in the East branch become
too warm, these wild rainbows returned to the main Delaware at the point where the West branch
enters it. They generally spend the warm summer months there in the cool waters of the refuge.
In the fall, these fish will then return to the East branch and the Beaverkill as the waters there
return to a cooler temperature. They remained through the winter months, until a stimulus
causes them to move again.
Many of these rainbow trout that are native to the Delaware River system grow up in the
main stem, or a tributary. Once these fish become adults, they move throughout both of the east
and west branches of the river system. As young fish, these rainbow trout become accustomed
to the entire system. The locations of the thermal refuge areas are imprinted into the fish, which
means that they possess the knowledge when they are born. The rainbow trout also learn where
the mouths of the tributaries are, and that this is where there is adequate cold water to survive.
The rainbows from the main stem of the Delaware River learn that the cold water inflows from
the West branch keep the water cool enough in the summer months for survival. The fish will
recognize the area, and instinctively know to go there if they are somewhere where the water
becomes too warm for their comfort or survival. This temperature related movement is
imprinted with smell into these fish at a juvenile stage of development, as they grow into
adulthood (Phelps, 1994).
Many of the rainbow trout radio-tagged in this study also showed homing instincts while
spawning. Most of the rainbow trout tagged in the spring of 1996 spawned in tributaries. Of the
fish tagged, five of the seven spawned in tributaries. Three of these five spawned in the same
location in the spring ofthe next year, 1997. This homing instinct, particularly noticeable in
rainbow trout, is a genetic trait carried out by migratory strains present in the Delaware River
system. The rainbow trout in the Delaware River system spawn in the tributaries of the Main
Delaware River. As adults, they lay their eggs in these tributaries. The young juveniles mature
in these streams for two to three years. In this juvenile stage, they imprint different stream
33
characteristics, such as stream smell and flow, in relation to their body functions. These fish
learn where the cold water flows are from and become accustomed to these areas (Phelps, 1994)
. Once these small trout reach three years of age, most exit these tributaries to grow to adulthood
in the main Delaware River. Once these fish reach brood adult age, when they are mature
enough to bear young, they return to the tributaries to spawn. This homing process is solely
driven by imprintation of the tributary smell into the fish at a young age, which remains there,
for life in the adult fish (Phelps, 1994).
In the Delaware River system, specific homing characteristics of the rainbow trout are
most noticeable during the spring spawning migration. Fish tagged in the Delaware River
showed homing instincts into the tributaries of the Delaware, as well as those tributaries of the
East and West branches. Read Creek, an East branch tributary, is a particularly important
spawning creek for rainbow trout. This creek has particularly good gravel areas, as well as cover
for fish to spawn in the streambed. A secondary tributary used by many of the rainbow trout
repeatedly was Balls Creek located on the West branch. Homing instincts are very important,
because the trout return to the same specific area during spawning which also allows us to locate
nurseries for the young wild trout. These nurseries are located at the same areas year after year,
and are the locations upon which the entire trout populations of the river are dependent. As the
adult trout enter these nursery areas, they are carrying and delivering the offspring of the future
populations, which must produce a large juvenile trout base if the species is to continue. If the
juvenile base is depleted, the resulting brood age adults will suffer, and the species will struggle
to survive. The rainbow trout that are present throughout the entire river system are genetic
offspring of the wild rainbow trout patterned around the main Delaware. These trout may have
relocated while growing to adulthood, but were originally born and raised in one of the small
tributaries. These tributaries are important nursery areas for the Delaware River trout
population, and should be protected during spawning seasons.
The rainbow trout present are especially familiar with the changing conditions that
frequent the Delaware River system. They become accustomed to the cold water thermal
refuges, know where they are located, and migrate to them at the first signs of thennal stress to
insure their greatest chance of survival. The rainbow trout of the Delaware river system,
particularly those located in the lower reaches of the Beaverkill River and the lower East branch,
were raised in a tributary. They imprint, and recall, these tributary locations by smell, so that
under warm water conditions, they often move up or downstream seeking a cold water tributary
mouth or a large cold water refuge area. Many rainbow trout that are residents of the East
branch swim upwards of24 km (15 miles) downstream to the main Delaware branch to the large
thermal refuge located where the cold west branch waters enter the main stem.
Thermal Refuges:
The fish that were tagged used many known thermal refuges. Through the study, other
thermal refuges were discovered throughout the system. Many fish travel large distances to
relocate to these areas in search of the cooler temperatures.
34
The largest known thermal refuge is where the West branch of the Delaware enters the
main stem. The entire 27.2 km (17 miles) of river acts as a large refuge because of the cold
water, bottom release flows from the Cannonsville Reservoir throughout the summer months.
These releases provide the quality water needed for trout growth and survival. A second known
refuge in the Delaware system is located just below Hancock, NY on the Pennsylvania side of
the river where the West branch empties into the Delaware. This area is an important summer
thermal refuge area for both brown and rainbow trout from all areas. They come from the lower
Beaverkill, the lower East branch, and the main Delaware River during the warmer summer
months. Another known refuge being utilized in the system was located in the Beaverkill River.
Cold water mountain stream flows from Horton Brook, a tributary to the Beaverkill, enter it just
above Horton, NY. Large numbers of trout from the Beaverkilliocate there during the summer
because the water levels become quite low and warm.
Many fish traveled to areas previously unknown as thermal refuges. They included the
mouths of tiny streams, which entered the main Beaverkill. Lehmberg (1998) explains that
warm water temperatures often force trout to move, and they often relocate at the mouths of
colder tributary streams. Many small tributary streams such as Abe Lord Creek, Bouchoville
Brook, Hankins Brook, and the mouth of the Equinunk Creek, all provided the trout with cold
flows throughout the summer. Other refuges were also discovered, shown in figure 7. Other
trout migrated to areas within the main Delaware and the East branch to congregate. Deep pools,
like the one located just below the town of Harvard on the East branch, provided trout with the
necessary cold water due to springs in the riverbed.
A second large spring was found near Lordville, on the main Delaware, at the bottom of a
large pool. Another deep pool was above Long Eddy on the Delaware River. This pool provided
the trout with plenty of cool water because of its depth as well as springs seeping into the pool.
Many trout congregate in this pool during the warm summer months.
Spawning streams:
Documentation of spawning streams was done throughout the radiotelemetry study. In
the wild trout population, brown or rainbow, spawning or natural reproduction is crucial to
population growth. By knowing where these fish spawn, we are able to find out which areas need
protection in order to insure succession of the species. Almost all of the tributaries that enter
into the Delaware River system serve as spawning streams and therefore nursery areas for the
juveniles. Some streams receive more fish during spawning runs solely because of size or
streambed characteristics. Some streams are simply too small, and don't allow large runs of fish
to find suitable substrate to spawn.
Brown trout radiotagged in this study utilized tributaries in both the fall of 1996 and the
fall of 1997 for spawning purposes. Brown trout utilized tributaries of the Beaverkill, East
Branch, West branch, and the main Delaware River to spawn during the falls of 1996 and 1997.
Both male and female fish selected spawning streams in the study period. Some streams
received more fish than others. Major spawning tributaries that were documented in the study
were Sands Creek, Shehawken Creek, Roods Creek, and Balls Creek on the West branch of the
35
Delaware. Horton Brook was a major spawning tributary for brown trout on the Beaverkill
River. Abe Lord Creek was a major spawning tributary for the Main Delaware River.
Rainbow trout radio-tagged in this study utilized tributaries to spawn in both the springs
of 1996 and of 1997. In the spring of 1996, radio-tagged rainbows were observed in tributaries
of the East, West and Main Delaware River branches.
Balls Creek and Shehawken Creek are both tributaries of the West branch that were
utilized by rainbow trout for spawning activity. Abe Lord Creek and Callicoon Creek, both
tributaries to the Main Delaware River were used in the spring of 1996. In 1996, radio-tagged
trout utilized Read Creek, an East branch tributary, as a spawning stream. In 1997, most ofthese
same streams saw fish return to them to spawn the following spring. One major stream that was
previously unknown as a major spawning tributary was Read Creek on the East branch ofthe
Delaware River. This creek is a spawning area and nursery stream for most of the rainbow trout
in the entire Delaware River system. Five radiotagged fish entered this tributary to spawn in the
spring of 1997. Numerous others were observed spawning in both 1996 and 1997. This is a
very important spawning tributary to the whole river system and should be protected. Because
so many of the tributaries are used as spawning areas by fish throughout the entire Delaware
system, these areas should be closed to fishing to protect future generations ofthe trout
populations in the Delaware River system.
36
LITERATURE CITED
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9267.
Arnold, D.E., 1.T. Nichols, and R.A. Bachman. 1987. Potamodromous spawning migrations of
brown trout, with a case study from Pennsylvania. Pennsylvania State University Cooperative
Fish and Wildlife Research Unit, Final Report 280, University Park.
Behnke, R. 1. 1991. The Species, p. 220-222, p. 310 in 1. Stolz and J. Schnell, eds. Trout.
Stackpole Books. Chicago.
Courtois, L.A. 1981. Light weight, adjustable, and portable surgical table for fisheries work in
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Craig-Bennett, A. 1931. The reproductive cycle of the three-spined stickleback(Gasterosteus
aculeatus), Linn. Phil. Trans.B, 219,197.
Elliot,1.M. 1975. The growth rate of brown trout (Salmo trutta L.) fed on maximum rations.
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Fontaine, M. and Koch, H. 1950. Les variations d' euryhalinite et d' osmoregulation chez lez
poissons. F. Physiologie, Paris, 42, 287.
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Hoar, W.S. 1953 Control and Timing ofFish Migration. Biol.Rev.28:437-452
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diel temperature fluctuations on specific growth and mortality and yield ofjuvenile rainbow
trout(Salmo gairdneri). Journal of the Fisheries Research Board of Canada. 34:639-648.
Langan, David A. 1997. Trout Movements in the Beaver Kill- Delaware Watershed. TROUT
on internet
Lehmberg, V. 1998. A Deadly Warming. Pages 36-38 IN FLYFISHER, Magazine of the
Federation of Fly Fishers. Winter Issue.
McBride, N.D. 1997.Progress Report 1995 Delaware Tailwaters Radio Telemetry Study. Region
4 DEC Fisheries Office, Stamford, NY.p.1-27.
Meyers, L S., T.F. Thuemler, and G.W. Kornely. 1992. Seasonal Movements of Brown Trout in
NortheastWisconsin. North American Journal of Fisheries Management 12:433-441.
37
Nielsen, J. L. and T. Lisle.1994. Thennally Stratified Pools and Their Use By Steelhead in
Northern CA Streams. Tran. of Am. Fish Soc. 123:613-626.
Nielsen, L. A, and D. L. Johnson. 1983. Fisheries Techniques.p. 371-379. Southern Printing
Company, Inc, Blacksburg, Virginia.
Nikolsky, G.V. 1963. The Ecology of Fishes. p. 44-56. Academic Press, London and New York.
Northcote, Thomas G. 1991 Migration. p. 84-89 in 1. and 1. Schnell,eds. Trout. Stackpole
Books. Chicago.
Phelps, Steve. 1994. Genetic Conservation Management. Washington Department ofFish and
Wildlife, Washington Genetic Diversity Unit. Annual Publication update.
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frequency transmitters in fish. Progressive Fish Culturist 44(1):41-43.
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river during 1987. NYSDEC, Region 4 Fisheries Office, Stamford,NY:32pp.
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and on the WestBranch of the Delaware river downstream of Cannonsville Reservoir in
1989,1990, and 1991. NYSDEC, Region 4 Fisheries Office, Stamford, NY:108pp.
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Fisheries Society, Library of Congress.
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fishes from eastern Lake Erie and the upper Niagara River: a review of the literature.
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Stuart, T.A. 1953. Spawning migration, reproduction and young stages ofloch trout (Salmo
trutta L.). Sci. Invest. Freshw. Salmon Fish. Res. Scotl. Horne Dep. 5:1-39.
Tilzey, R.D. 1977. Repeat homing of brown trout (Salmo trutta L.) in Lake Eucumbene, New
South Wales, Australia. Journal of the Fisheries Research Board of Canada. 34(8):1085-1094.
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Michigan.
38
Winter,lD. 1983. Underwater biotelemetry. p. 371-395 in Fisheries Techniques. American
Fisheries Society, Bethesda, Maryland.
39
Appendices
Appendix A
Table of fish tagged in 1996 on the West Branch of
the Delaware River
Appendix B
River
Table offish tagged in 1996 on the Main Delaware
Appendix C
Table of fish tagged in 1996 on the East Branch of the
Delaware River
Appendix D
Table of fish tagged in 1996 on the Beaverkill River
4
Data for trout radlotagged In East Branch Delaware River In 1996
Fish ID # Frequency (MHz)
EB1-2
53.671
EB2-2
53.572
EB3-2
52.761
EB4-2
53.621
EB5-2
53.66
EB6-2
52.702
EB7-2
52.772
EB8-2
53.892
EB9-2
52.801
EB1o-2
53.802
EB11-2
53.631
EB12-2
52.681
EB13-2
52.811
EB14-2
52.522
EB15-2
52.781
EB16-2
53.651
EB17-2
53.581
EB18-2
52.742
Tagging Date
4/11/96
4111/96
4/11/96
4/25/96
4/25/96
4/25/96
4/25/96
5/9/96
5/9/96
5/9/96
5/9/96
5/16/96
5/31/96
5/31/96
6/5/96
6/5/96
6/5/96
8/12/96
Collection Method
electrofishing
eJectrofishing
electrofishing
eJectrofishing
electrofishing
electrofishing
electrofishing
electrofishing
electrofishing
electrofishing
electrofishing
angling
angling
angling
electrofishing
eJectrofishing
electrofishing
angling
Species Sex
BT
F
BT
M
RT
F
BT
F
BT
M
BT
F
BT
M
BT
F
BT
M
BT
M
BT
F
BT
F
BT
F
RT
F
RT
F
RT
F
RT
F
RT
F
length (mm) Age (yrs) Origin
414
4
wild
497
5
wild
403
3
wild
440
4
wild
435
3
wild
408
3
hatcherY
431
4
wild
405
4
wild
493
5
wild
493
5
wild
450
3
hatche
446
5
wild
423
4
wild
391
3
wild
435
4
wild
410
3
wild
435
4
wild
435
4
wild
Appendix C
Data for trout radiotagged in Beaverkill River in 1996
Fish 10# Frequency (MHzj
BK1-2
53.59
BK2-2
53.642
BK3-2
52.792
BK4-2
52.591
BK5-2
53.692
BK6-2
53.791
BK7-2
53.771
Tagglng Date
3/19/96
3/19/96
4/3196
5/8/96
5117/96
5/17/96
5/18/96
Collection Method
electrofishing
el ectrofishing
electrofishing
electrofishing
angling
angling
electrofishing
S~iesSex
BT
BT
BT
BT
BT
RT
BT
Appendix D
F
F
M
M
F
F
F
length (mm)
400
475
510
455
492
470
411
Age (yrs) Origin
3
wild
5
wild
5
wild
3
hatchery
4
hatchery
5
wild
4
hatchery
40
Data for trout radlotagged In West Branch Delaware River In 1996
Fish ID#
WB 1-2
WB2-2
WB3-2
Freguency(MHz) TgggIng Date
53.782
4/5/96
53.681
4/5/96
53.562
4/15/96
WB4-2
53.813
4/15/96
WB5-2
WB6-2
WB7-2
WB8-2
WB9-2
WB10-2
52.632
52.67
52.742
52.651
52.681
52.611
5/29/96
5/30/96
5/30/96
6/18/96
6/18/96
6120/96
Collection Method Species Sex Length(mm) Age(yrs)
Origin
electrofishing
RT
F
406
4
wild
electrofishing
BT
F
403
5
wild
electrofishlng
BT
M
460
3
hatchery
eledrofishing
BT
M
422
4
wild
angling
BT
F
416
4
wild
angling
BT
F
387
3
hatchery
angling
BT
F
396
3
wild
electrofishing
BT
M
470
5
wild
electrofishlng
RT
F
427
4
wild
electrofishing
BT
M
424
4
wild
Appendix A
Data for trout radiotagged In Main Delaware River In 1996
Fish ID#
DR 1-2
DR 2-2
DR 3-2
DR 4-2
DR 5-2
DR 6-2
DR 7-2
DR 8-2
DR 9-2
DR 10-2
DR 11-2
DR 12-2
DR 13-2
DR 14-2
DR 15-2
DR 16-2
DR 17-2
DR 18-2
DR 19-2
DR 20-2
DR 21-2
Frequency (MHz)
52.382
52.54
52.531
52.551
52.692
52.661
52.581
52.641
52.571
52.601
52.622
52.711
53.702
52.72
53.6
53.611
52.731
52.711
52.561
52.752
52.661
Tagging Date
3/13/96
3/13/96
3/13/96
3/13/96
3/14/96
3/14/96
3/14/96
3/14/96
3/14/96
3/14/96
3/15/96
3/15/96
5/15/96
5/21/96
5/21/96
5/21/96
5/24/96
6/3/96
6/11/96
6/11/96
6/11/96
Collection Method
e1ectrofishing
e1ectrofishing
electrofishing
electrofishing
electrofishing
electrofishing
electrofishing
electrofishing
electrofishing
electrofishing
e1ectrofishing
electrofishing
electrofishing
eJectrofishing
eJectrofishing
electrofishing
electrofishing
electrofishing
electrofishing
electrofishing
electrofishing
Species
RT
RT
BT
RT
BT
BT
RT
RT
RT
BT
RT
BT
BT
BT
BT
BT
RT
BT
RT
RT
BT
Appendix B
Sex
F
F
F
F
F
M
F
F
F
M
F
F
F
F
F
M
F
F
F
F
F
Length (mm) Age (Yrs) Origin
376
3
wild
411
wild
3
462
hatchery
5
422
4
wild
460
5
wild
506
5
wild
454
5
wild
456
4
wild
446
4
wild
461
4
wild
462
wild
5
440
wild
5
503
wild
5
475
hatchery
5
415
4
wild
445
4
wild
413
4
wild
461
hatchery
3
390
wild
3
412
wild
4
445
wild
4