Movement Patterns of Coastal Cutthroat Trout (Oncorhynchus Clarki Clarki) in South Puget Sound, Washington 2006-2007

Item

Title

Eng Movement Patterns of Coastal Cutthroat Trout (Oncorhynchus Clarki Clarki) in South Puget Sound, Washington 2006-2007

Date

2008

Creator

Eng Haque, Sarah R

Subject

Eng Environmental Studies

extracted text

Movement Patterns of Coastal Cutthroat Trout (Oncorhynchus clarki clarki)
in South Puget Sound, Washington 2006-2007.

by
Sarah R. Haque

A Thesis
submitted in partial fulfillment
of the requirements for the degree
Master of Environmental Study
The Evergreen State College
June 2008

 2008 by Sarah R. Haque. All rights reserved.

This Thesis for the Master of Environmental Study Degree
by
Sarah R. Haque

has been approved for
The Evergreen State College
by

________________________
Amy Cook PhD
Member of the Faculty
________________________
Paul Butler PhD
Member of the Faculty
________________________
Joseph M. Jauquet, PhD, MES

________________________
Date

Abstract

Movement Patterns of Coastal Cutthroat Trout (Oncorhynchus clarki clarki)
in South Puget Sound, Washington 2006-2007.
Sarah Haque

Few studies have focused on the anadromous life-history form of coastal cutthroat. Migratory
pathways of coastal cutthroat, especially short-distance estuarine migrations, are even less
understood. Previous studies on coastal cutthroat trout primarily focused on freshwater systems
and described spawning and rearing characteristics, population structures, and genetics of the
freshwater life-history forms. This study collected baseline data on movements and nearshore
habitat use of two sample populations (Totten-Little Skookum Inlets and Squaxin/Hope Island) of
anadromous coastal cutthroat trout in South Puget Sound using acoustic tracking technology. A
total of forty cutthroat were captured in their marine environment, surgically implanted with
acoustic transmitters and tracked for eight months via a network of multi-channel acoustic
receivers placed throughout the deep South Sound area of South Puget Sound. Analysis suggested
a difference in movement patterns and distances traveled between sample populations; however,
the overall trend for both sample groups was a movement towards the extreme terminal areas of
the study area. A significant difference (P<0.05) in movements in relation to size-class was found
in both populations. Analysis of associations between movements of coastal cutthroat trout and
chum salmon migrations suggested the Totten-Little Skookum Inlets group displayed movement
patterns that closely followed both adult and juvenile chum salmon migrations. However,
movement patterns displayed from the Squaxin/Hope Island group did not reveal this same
behavior, however, indicating a lack of large-scale movements from broader and deeper-water
areas into more defined inlets in response to temporally discrete chum salmon migrations. Data
also suggested that anadromous coastal cutthroat in South Puget Sound may have a home range
distinct from Central and North Puget Sound and may heavily utilize specific habitats, such as
Skookum Inlet, during the fall and winter months.

Table of Contents
Page
List of Figures..............................................................................................................................vi
List of Tables ...............................................................................................................................vii
Acknowledgments........................................................................................................................viii
Introduction..................................................................................................................................1
Background.............................................................................................................................1
Study Area ...................................................................................................................................4
Methods and Materials.................................................................................................................6
Study Design...........................................................................................................................6
Instrumentation .......................................................................................................................8
Acoustic Transmitters ........................................................................................................8
Acoustic Receivers.............................................................................................................10
Field Procedures......................................................................................................................11
Receiver Locations and Deployment .................................................................................11
Sampling Cutthroat ............................................................................................................11
Surgical Implantation.........................................................................................................11
Results..........................................................................................................................................13
Movements of Sample Groups................................................................................................13
Depth Tag Readings...........................................................................................................13
Totten-Little Skookum Inlets Sample Group.....................................................................18
Squaxin/Hope Island Sample Group..................................................................................20
Comparison between Sample Groups ................................................................................21
Relationship of Movement Patterns to Size-Class of Cutthroat.........................................21
Relationship between Cutthroat Movement Patterns and Chum Run-Timing........................22
Discussion....................................................................................................................................22
Movements of Sample Groups................................................................................................22
Depth Tag Readings...........................................................................................................23
Totten-Little Skookum Inlets Sample Group.....................................................................24
Squaxin/Hope Island Sample Group..................................................................................25
Comparison between Sample Groups ................................................................................25
Relationship of Movement Patterns to Size-Class of Cutthroat.........................................27
Relationship between Cutthroat Movement Patterns and Chum Run-Timing........................27
Limitations ...................................................................................................................................28
Recommendations for Future Research .......................................................................................29
Management Implications............................................................................................................30
Literature Cited ............................................................................................................................32
Appendix 1: Angling protocols....................................................................................................34

iv

Appendix 2: Sampling Data.........................................................................................................35

v

List of Figures
Page
Figure 1: Coastal cutthroat trout distribution in Southern B.C., Washington, Oregon, and
California ....................................................................................................................................3
Figure 2: Study area map .............................................................................................................5
Figure 3: Frequency of time spent at each receiver represented by detections............................14
Figure 4: Geographic representation of Tag ID #54 movements.................................................15
Figure 5: Frequency of time spent at each receiver represented by detections............................16
Figure 6: Geographic representation of Tag ID #56 movements.................................................17
Figure 7: Geographic representation of Tag ID #828 movements...............................................19
Figure 8: Visual representation of cutthroat depth in relation to seafloor ...................................23

vi

List of Tables
Page
Table 1: Locations of the 12 receivers deployed for this study ...................................................6
Table 2: Locations of the existing network of receivers ..............................................................7
Table 3: Overview of acoustic tag type and specifications..........................................................9
Table 4: Acoustic tags used in this study.....................................................................................10
Table 5: Fish-to-Tag Ratio calculations used to determine tag type............................................12
Table 6: Summary table for cutthroat implanted with depth tags................................................13

vii

Acknowledgments
This study could not have been possible without the collaborative efforts of many
individuals and organizations, all of which deserve sincere thanks and acknowledgement.
Funding and support for this study were provided by Fred Goetz of the U.S. Army Corps
of Engineers, Tom Quinn of the University of Washington, the Squaxin Island Tribe’s Natural
Resources Department, the Nisqually Tribe, the American Fisheries Society’s 2005 Coastal
Cutthroat Trout Symposium, and the U.S. Fish and Wildlife Service.
I extend sincere gratitude to Fred Goetz for giving me the opportunity to be a part of such
an exciting endeavor and for having faith in my abilities to coordinate the South Sound Coastal
Cutthroat Acoustic Tracking Study in 2006.
I thank my faculty advisor and first reader, Amy Cook, for her support and assistance
through this process. Her lighthearted spirit and positive attitude helped to inspire me. Sincere
thanks to Joe Jauquet for his technical and emotional support throughout this study. His words of
kindness and wisdom helped guide me through the fog when it was most critical. I also thank
Paul Butler for his thoughtful editing and for his easy going nature, which always eased my mind.
I also sincerely thank and acknowledge Chris Ellings, Florian Leischner, Kyle
Brakensiek, Joe Jauquet and Fred Goetz; the core group of dedicated cutthroat “aficionados” and
scientists who spent their time and energy to help develop the study plan for this project.
Special thanks to all the angling volunteers who spent their weekend to wrangle in the
cutthroat sampled for this study: Shawn Zaniewski, Bryan Thompson, Chris Ellings, Joe Jauquet,
John Means, Florian Leischner, Lance Winecka, Kelly Cunningham, Larry Phillips, Jason
Lundgren, and the random stranger out on the water willing to help out for a few hours.
I thank Levi Keesecker for all of his diligence in creating the GIS maps used in this
document. His humor, support, and patience with me throughout this process should be
acknowledged and praised. It is also my pleasure to acknowledge Colleen Seto for her keen
editing skills, critical eye, and unyielding support.
I extend a very special thanks to Shawn Zaniewski for his unwavering support and
patience from the conception of this project to the end. I credit much of my academic success to
the love and encouragement I received from him through the course of my graduate studies.
Lastly, I would like to thank my parents for their encouragement and support. My
mother’s kind words and my father’s humorous stories of empathy helped me stay the course.

viii

Introduction

Most previous studies on coastal cutthroat trout (Oncorhynchus clarki clarki) have
occurred in freshwater systems and have primarily focused on describing spawning and rearing
characteristics, population structures and genetics of adfluvial or fluvial life-history forms. Few
studies have been conducted on the anadromous life-history form and these studies are limited in
scope. Very little research has examined the extent of coastal cutthroat nearshore habitat use such
as movement patterns and environmental “drivers” (cues), if any, that may dictate these
movements. Studies of migratory pathways of coastal cutthroat, especially short-distance
estuarine migrations, are even less common (Johnson et al 1999). Most of the studies conducted
on anadromous coastal cutthroat have concluded that this subspecies utilizes the marine
environment for feeding from spring through late fall and early winter and that they generally do
not overwinter in the marine environment (Northcote 1997, Trotter 1997).
The objective of this study was to collect baseline data on small-scale movements and
nearshore habitat use of anadromous coastal cutthroat trout using acoustic tracking technology.
The purpose was to observe and describe the temporal and spatial associations between the
movements of anadromous coastal cutthroat trout in South Puget Sound, chum salmon
migrations, and environmental conditions such as tides and daily cycles. Observations of coastal
cutthroat behavioral patterns such as saltwater overwintering activities, habitat use, inlet fidelity,
and migratory distances were key components. This research was an attempt to answer the
following questions:
1) Do anadromous coastal cutthroat trout have directed movement patterns, specifically
in relation to chum salmon migrations, tides, and/or diel patterns?
2) What is the nearshore habitat use of anadromous coastal cutthroat trout, specifically in
relation to overwintering habitat use?

Background
The coastal cutthroat trout is an extremely complex organism, and has one of the most
complex life-histories of the Pacific salmonids (Oncorhynchus spp) (USFWS 2002). Save for a
few select studies currently taking place in Puget Sound marine areas (Goetz, University of
Washington pers. comm), the coastal cutthroat remains one of the least studied species of the
Pacific salmon (Ellings 2003).

1

Coastal cutthroat have at least three distinguishable life-history forms, which include
freshwater resident, freshwater migratory, and anadromous forms (Trotter 1997; Johnson et al
1999). Life-history forms can exist without interbreeding within the same geographical range
resulting in several distinct stocks within small streams (WDFW 2000; Garrett 1998.). Research
also suggests that genetic similarities between different life-history forms of coastal cutthroat
trout within the same geographical range are more closely related than similar life-history forms
that are separated geographically (Garrett 1998; Williams et al 1997).
The resident life-history form of coastal cutthroat trout remains in freshwater and is nonmigratory, often remaining in the same stream segment for the duration of its life cycle. The
freshwater migratory life-history form migrates from smaller tributaries to larger tributaries or
mainstem rivers. This life-history form may also make migrations between tributaries, lakes,
ponds, and/or reservoirs (Johnson et al 1999; Federal Register 2002). The anadromous lifehistory form, also known as “sea-run” cutthroat, migrates between marine and freshwater habitats
and has a freshwater rearing period ranging from 1-4 years (DNR 1997). This life-history form is
sometimes referred to as amphidromous due to evidence suggesting that individuals of this form
often migrate between freshwater and marine water habitats for “reasons other than spawning”
(Garrett 1998).
The coastal cutthroat trout’s marine distribution is along the Pacific Coast of North
America and it ranges from the Eel River in northern California, north to the Prince William
Sound in Alaska. Inland distribution ranges from the Alaskan Coastal Range to the crest of the
Cascade mountain Range of Washington and Oregon (Johnson et al 1999; Federal Register 2002).
Although the marine habitat of anadromous coastal cutthroat is generally thought to be
limited to nearshore habitats, data compiled by the U.S. Fish and Wildlife Service (USFWS)
indicate that cutthroat migration patterns and distances traveled offshore are unclear (Trotter
1989; Northcote 1997; Federal Register 2002). Individually marked cutthroat along the
Washington and Oregon Coasts have been reported at distances of 10-45 km offshore of the
Columbia River and 72-290 km offshore of the Oregon coast (Federal Register 2002). Due to the
uncertainty of offshore marine migration patterns, it is not clear whether these fish actually move
offshore in search of food, are transported with prevailing currents, or are forced to deeper
offshore waters to find refuge from the harsh conditions of the surf (Federal Register 2002;
Trotter 1989).
Under the Endangered Species Act, a population is considered an Evolutionary
Significant Unit (ESU) if the population or group of populations is “1) substantially
reproductively isolated from other populations, and 2) contributes substantially to the ecological

2

or genetic diversity of the biological species” (Johnson et al 1999; USFWS 1973). The
Northwest coast supports six distinct populations of coastal cutthroat trout: the Olympic
Peninsula, Oregon Coast, Puget Sound, Southern Oregon/California Coast, Southwest
Washington/Columbia river, and Upper Willamette River, all of which were identified as
Evolutionary Significant Units by the Biological Review Team (BRT) (Figure 1) (Johnson et al
1999).

Figure 1: Coastal cutthroat trout distribution in Southern B.C., Washington,
Oregon and California. Distribution is visually displayed by Evolutionary Significant
Units. (NOAA, 1999).

The population status of coastal cutthroat trout is variable and often inconclusive and the
methods utilized to establish population status are often unreliable (Federal Register 2002).
However, data analysis from various studies indicates that many populations of anadromous
coastal cutthroat have declined from historic levels while freshwater forms tend to remain well
distributed and “at reasonable densities” (Federal Register 2002; ODFW 1997; USFWS 2002).
Research on the diet and stable isotope composition of anadromous coastal cutthroat trout
in South Puget Sound has illuminated the relationship of chum salmon (O. keta) to coastal
cutthroat (Jauquet 2002; Ellings 2003.). These studies found that anadromous cutthroat utilize

3

chum salmon or “salmon derived nutrients” as an important food source when salmon are present
(Ellings 2003). Regardless of the abundance of other food sources, anadromous cutthroat show
indications of altering their diet to one consisting primarily of juvenile chum salmon or salmon
eggs (Jauquet 2002).
In a preliminary study conducted in July 2005, 17 coastal cutthroat trout were captured in
South Puget Sound near Squaxin Island and implanted with ultrasonic acoustic transmitters (tags)
(Goetz, University of Washington, and Steltzner, Squaxin Island Tribe pers comm). The cutthroat
were tracked by a network of submersible multi-channel acoustic receivers. The 2005 study
primarily provided guidance on surgical implantation of acoustic tags in anadromous coastal
cutthroat and also provided some preliminary information about the movement patterns of a
subset population of South Puget Sound coastal cutthroat.

Study Area

The study area for this research was the southern extent of South Puget Sound,
Washington from mid-Pickering Passage south, including Hammersley, Totten, Little Skookum,
Eld, and Budd inlets, and east to Dana Passage (Figure 2). This area of South Puget Sound is
often referred to as the “Deep South Sound” (Steltzner, Squaxin Island Tribe pers comm;
Preikshot et al 2001).

4

Figure 2: Study area map. Receivers deployed for the 2006-2007 acoustic tracking project
are visually represented by red points. Permanent receivers, managed by the Squaxin Island
Tribe, are represented by green triangles. Numbers next to receivers are receiver ID numbers.
All receivers are shown with the 400 m maximum detection radius, represented by a black
ring. Receivers displayed with an “X” are representative of units that were lost or damaged,
resulting in no retrievable data.

5

Two sample areas were chosen, Squaxin/Hope Island vicinity and Totten-Little Skookum
Inlets, to increase data coverage to a larger spatial network of receivers than was previously
established in the 2005 preliminary study (Goetz, University of Washington, and Steltzner,
Squaxin Island Tribe pers comm).

Methods and Materials
Study Design
This acoustic tracking study was a collaborative effort between the author, the University
of Washington, the Squaxin Island and Nisqually Tribes, and other scientists. This study built on
the preliminary 2005 study, with the goal of expanding anadromous coastal cutthroat acoustic
tracking efforts in South Puget Sound.
In this study, 40 coastal cutthroat trout were surgically implanted with acoustic tags and
tracked for 8 months (September 9, 2006 - May 15, 2007) via a network of receivers in the Deep
South Sound (Figure 2). Eleven of 12 receivers were placed in marine water areas and one was
placed in freshwater. The eleven receivers placed in marine waters were placed in nearshore areas
in and around Squaxin Island and Totten-Little Skookum, Hammersley, and Eld Inlets, with the
highest density of receivers placed in Totten Inlet. The receiver deployed in freshwater (receiver
7064) was placed in Skookum Creek (Table 1).
Table 1: Locations of the 12 receivers deployed for this study

Receiver
Number
3345
2113
3371
3364
4475
7064
6978
3350
2117
6972
2118
3347

Location
Southwest shoreline of Squaxin Island
Hammersley Inlet
Southeast shoreline of Upper Totten Inlet
Northwest shoreline of Upper Totten Inlet
Little Skookum Inlet
Skookum Creek
Northwest shoreline of Lower Totten Inlet
Southeast shoreline of Lower Totten Inlet
Hunter Point
Southeast shoreline of Middle Eld Inlet
Southeast shoreline of Lower Eld Inlet
Northwest shoreline of Lower Eld Inlet

6

The sites for the 12 receivers were chosen to gain the most extensive coverage with the
equipment available and to specifically observe the coastal cutthroat trout sample populations in
the Deep South Sound. Receivers were located in spatial relation to an existing network of nine
receivers that were part of studies by the Squaxin Island Tribe, Washington State Department of
Fish and Wildlife (WDFW), and the University of Washington that targeted other Pacific Salmon
populations (Table 2).
Table 2: Locations of the existing network of receivers

Receiver
Number
4479
6154
6160
PL1
6158
4476
5044
4327
4205

Location
Pickering Passage
North shoreline of Hammersley Inlet at mouth
South shoreline Hammersley Inlet at mouth
North Peale Passage
South Peale Passage
North shoreline of South Dana Passage
South shoreline of South Dana Passage
West shoreline of Budd Inlet
East shoreline of Budd Inlet

No data were retrieved from two of the 12 receivers deployed for this study. Receiver
2113 in Hammersley inlet was lost, and receiver 3347 in Lower Eld Inlet was damaged. Receiver
3347 was sent to the manufacturer for data extraction from the flash memory, but no data were
recovered. No data were retrieved from the two receivers in Budd Inlet (4327 and 4205) because
the receivers were not recovered by the Squaxin Island Tribe (Steltzner, Squaxin Island Tribe
pers comm). Due to the exceptional number of continuous detections at receiver 4475 in Little
Skookum Inlet, the memory reached capacity in November 2006. No data were collected at this
site for four months because the receiver was not recovered until March 2007.
The 12 receivers deployed for this study were retrieved in March 2006. A second
deployment of the Little Skookum Inlet and Skookum Creek receivers (receivers 4475 and 7064)
occurred on March 23, 2007 at the original locations and were recovered May 15, 2007. The
Skookum Creek redeployment was in response to detections heard from that location on the day
of retrieval, indicating that tagged cutthroat were still in Skookum Creek. The redeployment of
the receiver in Little Skookum Inlet was based on the assumption that any tagged cutthroat
leaving Skookum Creek and entering marine waters would pass the receiver in Little Skookum
Inlet.

7

This study design had two treatment groups of approximately 20 anadromous cutthroat
each, sampled from two locations (Figure 2). A two-sample design was used to observe coastal
cutthroat movement patterns and migratory behavior at differing spatial scales. Observing two
sample groups allowed for a comparison of movement patterns between and among the
subpopulations. It was hypothesized that data from the Squaxin/Hope Island Sample Group
would show whether or not coastal cutthroat made large-scale movements from broad deep-water
areas into smaller, shallower, and more defined inlets in response to temporally discrete chum
salmon migrations, or other factors. It was also hypothesized that the coastal cutthroat data from
the Totten-Little Skookum Inlets Sample Group would provide insight into behavioral patterns,
including inlet fidelity and saltwater over-wintering habitat use.
The sampling time frame was based on known run-timings of South Puget Sound chum
salmon. The various inlets of South Puget Sound have discrete chum salmon run-timings,
providing an opportunity to observe the migratory behavior of coastal cutthroat trout in relation to
the seasonal variation in chum salmon run-timing. It was hypothesized that coastal cutthroat
found in South Puget Sound have distinct movement patterns associated with chum salmon
spawning migrations and out-migrating juvenile chum salmon. Observations should show
whether or not coastal cutthroat trout migrate in and out of inlets to take advantage of different
chum runs, or if they commit to specific chum runs.

Instrumentation
VEMCO Limited (VEMCO) is the leading company in designing and manufacturing
underwater acoustic telemetry equipment. VEMCO-coded Transmitters and VR2 submersible
multi-channel acoustic receivers were the primary data collection equipment used in this study.

Acoustic Transmitters
The acoustic transmitters (tags) use a single frequency (69 kHz) coding scheme allowing
all VEMCO tags to be detected by all VEMCO receivers. Tags are available in a variety of sizes,
power and sensor outputs, and battery life. Several tags are capable of recording
depth/temperature data (Table 3).

8

Table 3: Overview of acoustic tag type and specifications (VEMCO, 2004).

Tag
Family

Minimum

Maximum

Size:

Size:

Diameter Length (mm), Length (mm),

V7

7 mm

V9

9 mm

V13

13 mm

V16

16 mm

Weight in

Weight in

Water (g)

Water (g)

17.5 mm,

20.5 mm,

0.7 g

0.8 g

20 mm,

46 mm,

2g

3.1 g

36 mm,

44 mm,

6g

6.6 g

52 mm,

96 mm,

9g

16 g

Sensors:
Power

T-Temp

Battery Life2 (90

Output (dB)

P-Pressure

second Delay3)

(depth)

136

None

200 days

139-147

T,P,TP

400 days

147-155

T,P,TP

700 days

149-159

T,P,TP

10 years

These tags emit a series of pings, or pulse trains, which contain identification and error checking
information allowing the user to individually track multiple fish. The delay time between “pings”
is randomized and arranged around a nominal point, ensuring that other tags have the opportunity
to be detected by the receivers. The life of each tag depends on the battery size, power level, and
the delay time between pulse trains. Collisions of one or more tag codes occur when multiple tags
simultaneously transmit all or part of their pulse train. When this occurs, the pulse trains overlap
and neither transmission can be detected by the receiver. False detections may also occur from tag
collisions, generating artificial tag ID codes (VEMCO 2004).
Depth measurements are recorded by receivers as pressure readings, interpreted as the
depth of a fish from the water surface. For analysis, the pressure readings are transformed to a
depth measurement, in meters (m), through a regression formula provided by VEMCO. The depth
tags used in the study were programmed for depths up to 100 m. Resolution for a depth tag
programmed for 100 m is approximately 0.5 m with an accuracy of approximately plus or minus
three to five percent (±3-5%) (Webber, VEMCO pers comm).
This study used a combination of tags with varied delay times (Table 4). The study
duration was dependent on the battery life of the tags, which dictated the maximum data
collection period. Due to shared and donated equipment, the types of tags utilized were based on
availability from other scientists.

9

Table 4: Acoustic tags used in this study.

Tag Type

Delay Time

Approximate Battery Life

V9-6L

30-90

400 days

V9P-2L (Depth tag)

20-60

<400 days

V9-2L

20-60

<400 days

V7-2L

20-60

<200 days

Acoustic Receivers
The VR2 acoustic receiver is a single-channel submersible receiver capable of identifying
VEMCO-coded transmitters. The VR2 receivers are equipped with a hydrophone, receiver, ID
detector, data logger, and lithium battery and have a static depth rating of 500 m (730 psi).
Identification numbers (Tag ID codes) and time/date stamp are recorded as a tagged animal
travels within range of the receiver. Depth and temperature data can also be recorded (VEMCO
2006).
The detection range for the VR2 receivers is influenced by the distance of the fish from
the receiver, the power output of the tag, the tag delay time, and the number of fish
simultaneously present. The detection range is also strongly influenced by current, wind,
temperature, salinity, and ambient-and anthropogenic-induced noise conditions around the
receiver. Assuming ideal marine water conditions of low current, low wind, even seafloor
topography, and low noise levels, the maximum detection range of a V9 tag by the VR2 receiver
is approximately 400 m (Goetz, University of Washington pers comm; VEMCO 2007). The
maximum detection range of a V7 tag is approximately 200 m (Goetz, University of Washington
pers comm; VEMCO 2007). Studies have indicated an 80% detection rate for V9 and V7 tags
within a 400 and 200 m radius, respectively (Goetz, University of Washington, pers comm;
VEMCO 2007).
Each receiver can receive a maximum input of 256 coded sensor transmitters
(temperature or depth data tags) or up to 65,536 coded transmitters and is capable of storing over
300,000 valid detections. Receivers are downloaded to a computer running VR2 PC proprietary
software through a magnetic probe and VR PC Interface (VEMCO 2006).

10

Field Procedures
Receiver Locations and Deployment
Receiver locations were selected based on assumed habitats and travel routes of coastal
cutthroat trout. Receiver locations chosen were also in areas easily accessible and where receivers
could be deployed and retrieved without the use of SCUBA diving. Aquatic lands ownership and
critical or sensitive habitats were considered when choosing receiver locations so that receivers
were placed at least 70 m from the shoreline, outside of eelgrass or shellfish bed areas. The
appropriate State permits were obtained and private landowner permission was granted before
receivers were deployed.
Receivers in locations accessible only by boat were attached to a modified anchor and
buoy system and were deployed August 27 and Sept 7, 2006 (Hodgson, Nisqually Tribe pers
comm; Ellings, Ducks Unlimited pers comm). All receiver locations were recorded at the time of
deployment using a Garmin hand held GPS unit with coordinate system WGS 84. Water depth,
tide stage, time, and any additional pertinent notes relating to the site were recorded. Receivers
deployed from land (i.e. accessible by foot) were attached to “permanent” features such as docks
or tree roots. All receivers were attached to a mooring line according to the Cable Tie Attachment
Method specified in the VEMCO VR2 Receiver Manual (VEMCO 2006).

Sampling Cutthroat
Sampling of cutthroat was conducted on September 9 and 10, 2006 by hook-and-line
from boats. Volunteer anglers were used to capture fish. Sampling protocols were written and
strictly followed by all field volunteers in order to minimize stress and mortality of cutthroat trout
during sampling efforts (Appendix 1). Protocols included gear specifications, sampling location,
sampling restrictions, and fish handling instructions. Once cutthroat were safely landed, they
were placed in holding receptacles, transported to a centrally located surgery station, and
transferred to larger holding tanks. To minimize bias, there was no discrimination in ageclass/size sampled; however, no cutthroat less than 32 g was sampled due to tag-size restrictions.
Eighteen cutthroat were sampled from the Squaxin/Hope Island sample area on September 9 and
22 cutthroat were sampled from the Totten-Little Skookum Inlets Sample Area on September 10,
2006, for a total of 40 cutthroat.

Surgical Implantation
Cutthroat brought to the surgery station were transferred to 32-gallon holding tanks.
Fresh seawater was replenished regularly and aeration stones were used to maintain cool,

11

oxygenated water. Stress Coat, a chemical that adds protective coating to fish after handling, was
added to the tanks to minimize stress and the chance of infection following release.
To minimize the post-surgical effects of implantation due to tag-weight, minimum fishsize (weight) for particular sized transmitters was determined based on a weight-of-fish to tagweight-in-air ratio (fish-to-tag ratio). In this study the tag air-weight did not exceed 5% of the fish
weight (Table 5). This ratio was determined based on previous surgical trials from the 2005
preliminary cutthroat study, South Puget Sound Coho and Steelhead smolt tagging efforts and
published data (Steltzner, Squaxin Island Tribe pers comm; Hodgson, Nisqually Tribe pers
comm.; Kintama Research Corporation 2006; Welch et al 2001).
Table 5: Fish-to-Tag Ratio calculations used to determine tag type
(Hodgson, 2006).

Cutthroat weight (g)*
32-65
65-90
91-116

Tag Type
V7-2L
V9-6L,V7-2L
V9-2L, V9-6L, V7-2L
V9P-2L, V9-2L, V9-6L,
V7-2L
117+
*Cutthroat under 32g were not sampled
Cutthroat were sedated using Tricaine Methane Sulphonate (MS222) and surgically
implanted with coded acoustic tags. Surgery techniques and anesthetic doses were based on
USGS protocols and those outlined by Welch et al (2001). Surgical procedures were performed
by certified surgeons. Fork length (mm), weight (g), general location of capture, and release time
were recorded for each cutthroat (Appendix 2). Photographic records were also taken for each
fish.
After the tag was implanted, cutthroat were placed in recovery bins and closely
monitored until they recuperated from anesthesia and were observed swimming upright,
unassisted. Cutthroat swimming freely were held for an additional 15 minutes, but no longer than
30 minutes, before release. Most cutthroat were held 20-30 minutes after recuperation from
anesthesia. Recovery time was based on previous surgical trials on cutthroat trout and Coho and
Steelhead smolts (Steltzner, Squaxin Island Tribe pers comm; Hodgson, Nisqually Tribe pers
comm). Fresh seawater was added to the recovery bins at regular intervals and aeration stones
were used to maintain dissolved oxygen and temperature levels. Stress Coat was also added to
each tank. Cutthroat were released along the same shoreline where they were captured. Returning

12

fish to the exact locations where they were captured was not possible due to limited holding and
recovery space.

Results

Movements of Sample Groups
An original objective of this study included observing environmental factors such as tides
or diel patterns because they influence cutthroat movement patterns. This objective could not be
met due to the limited number and placement of receivers.
Reported results of cutthroat movements were based on cutthroat detected at two or more
receivers. A distinction between types of detection was made to more accurately report on
movement patterns by cutthroat detected at multiple receivers. While it is useful to know how
many cutthroat were detected, there were insufficient data to report on movements of cutthroat
detected by only one receiver (i.e. showed no movement).
The mean length of the 40 tagged coastal cutthroat was 316.9 mm with a range of 200450 mm. Mean weight of tagged cutthroat was 359.25 g with a range of 50-1010 g. Of 40
cutthroat sampled, 37 (93%) were detected at least once and 27 (73%) were detected at two or
more receivers.

Depth Tag Readings
Of the 40 cutthroat tagged, five larger fish across both sample areas were implanted with
depth tags (Table 6).

Table 6: Summary table for cutthroat implanted with depth tags.

Tag ID
code #

Capture site

53

Totten Inlet-North Shore

54

Squaxin Island-Western
Shoreline

55

Little Skookum Inlet

56
57

Hope Island
Hope Island

Sample Group
Totten-Little
Skookum Inlets
Squaxin/Hope Island
Totten-Little
Skookum Inlets
Squaxin/Hope Island
Squaxin/Hope Island

Capture
date

Length
(mm)

Weight
(g)

09/10/2006

360

450

09/09/2006

440

950

09/10/2006

400

670

09/09/2006
09/09/2006

350.5
450

560
1010

Among the cutthroat listed in Table 6, four (80%) were detected at least once and three (60%)
were detected at two or more receivers. Tag ID #57 had no detections. For the four cutthroat

13

detected, mean depth for daylight hours was 1.30 m, variance = 0.34, n = 14693. Mean depth for
non-daylight hours was and 0.63 m, variance = 0.13, n = 21298. A Pooled Two-Sample t-test
showed a significant difference between depths observed during daylight and non-daylight hours
(P<0.001). Distinction between daylight and non-daylight hours was based on the U.S. Naval
Observatory Astronomical Applications Department
(http://aa.usno.navy.mil/data/docs/RS_OneDay.php).
Tag ID #53 was first detected on the day of capture (September 10, 2006) at receiver
4475 in Little Skookum Inlet and continuous detections were recorded through September 13,
2006. This cutthroat was not detected again until November 6, 2006 for approximately one hour.
Tag ID #53 was last detected in Skookum Creek at receiver 7064 on November 8, 2006. Depth
detections recorded averaged 1.32 m. Depth measurements recorded at the freshwater location in
Skookum Creek (receiver 7064) were unusable due to negative depth readings.
Tag ID #54 was first detected at receiver 6160 one day after tag implantation (September
9, 2006) and subsequently detected at receiver 3345 on September 21, 2006. Although not
continuous, detections for this cutthroat were recorded at receiver 3345 through January 2, 2007
with 372 detections spanning 24 days during December. After its long residency time, this
cutthroat was highly mobile, registering detections at receivers 6798, 3350, 2117, 6972, and
2118, consecutively. Tag ID #54 was last detected on February 7, 2007 at receiver 2118. Mean
depth for this cutthroat was 0.72 m.
The frequency of detections Tag ID #54 registered at a given receiver is displayed in
Figure 3. A time budget was not used because the detections were not always continuous.

Figure 3: Frequency of time spent at each receiver represented by detections

All measurements and assumed travel routes for Tag ID #54 were based on the shortest
distance between receivers. A graphic representation of these movements is provided in Figure 4.

14

Figure 4: Geographic representation of Tag ID #54 movements. Arrows represent the
assumed travel routes. First detection recorded was at receiver 6160. Last detection
recorded was at receiver 2118.

15

Tag ID #55 was detected at only receiver 4475 at a mean depth of 0.88 m. Detections
were continuous September 10 through November 4, 2006. The memory for this unit reached
capacity in November; therefore, it was not possible to determine whether this fish moved out of
detection range after the last detection.
Tag ID #56 was first detected at receiver 6160 the day of capture (September 9, 2006)
and 99% of the detections were recorded during non-daylight hours September 9-17, 2006. This
cutthroat was subsequently detected at receivers 3350, 6798, and 7064 during December 15 and
18, 2006. This tag was detected again at receiver 7064 on March 2, 2007. No detections were
recorded at receiver 4475 before this tag was detected on either date at receiver 7064 in Skookum
Creek. This data gap was likely due to that the memory for receiver 4475 reaching capacity in
November 2006. Mean depth for this cutthroat was 0.96 m. Figure 5 describes the number of
detections recorded at each receiver.

Figure 5: Frequency of time spent at each receiver represented by detections

A graphic representation of movements by Tag ID #56 is provided in Figure 6. Assumed
travel routes were based on the shortest-distance between receivers.

16

Figure 6: Geographic representation of Tag ID#56 movements. Arrows represent the
assumed travel routes. First detection was recorded at receiver 6160. Last detection was
recorded at receiver 7064.

17

Totten-Little Skookum Inlets Sample Group
Of the 22 cutthroat tagged from Totten-Little Skookum Inlets on September 10, 2006 ten
were captured from Little Skookum Inlet and 11 were captured in Totten Inlet (Appendix 1). No
capture location was recorded for Tag ID #3123. Of the 22 cutthroat in this sample group,
21(96%) were detected and one, Tag ID #487, had no detections.
Of the 21 tags detected, 20 (95%) were not detected at receivers outside of the TottenLittle Skookum Inlets Sample Area and these 20 were all detected in Little Skookum Inlet at
receiver 4475. Thirteen tags (62%) were detected by two or more receivers. Eight (38%) were
detected only at receiver 4475. Of the 13 cutthroat detected by two or more receivers, 12 (92%)
were detected in Little Skookum Inlet at receiver 4475 and of these tags 8 (67%) were also
detected at receiver 7064, located in Skookum Creek. Of the 13 cutthroat detected at multiple
receivers, 12 (92%) stayed in the sample area.
Only one cutthroat, Tag ID #828, used areas outside of the Totten-Little Skookum Inlets
Sample Area (Figure 7). This cutthroat was detected at receivers 6160 and 6154 at the mouth of
Hammersley Inlet on September 11 and at receiver 2117 located near Hunter Point on September
12-13, 2006. This fish moved back into the Totten-Little Skookum Sample Area on September
13th, approximately three days after release, and remained within the study area for the duration
of the study. This cutthroat was intermittently detected in Skookum Creek at receiver 7064
November 3, 2006 through March 21, 2007 and last detected in Little Skookum Inlet at receiver
4475 on May 10, 2007.

18

Figure 7: Geographic representation of Tag ID #828 movements. Arrows represent the
assumed travel routes. Dashed line represents sample area of Totten-Little Skookum Inlets
Sample Group. First detection was recorded at receiver 6160. Last detection was recorded at
receiver 4475.

19

Nine of the ten cutthroat (90%) captured from Little Skookum Inlet were detected at least
once. Tag ID #487 had no detections. Seven of the nine cutthroat (78%) detected were not
detected outside of the inlet or Skookum Creek. Six (66%) were detected only at receiver 4475.
Three (33%) tags were detected at two or more receivers.
Of the three tags detected at two or more receivers, two (67%) of the tags, Tag ID #828
and #3124, were detected outside of Little Skookum Inlet, but were last detected in Little
Skookum Inlet. Tag ID #479 was detected at receivers 4475 and 7064 in Little Skookum Inlet.
All of the cutthroat captured from Totten Inlet were detected at least once and nine (82%)
were detected by two or more receivers. Five (46%) were detected at receivers in Totten and
Little Skookum Inlet, including Skookum Creek and five (46%) were detected only in Little
Skookum Inlet or in Skookum Creek. Of the five tags detected only in Little Skookum Inlet or
Skookum Creek, two (40%) were detected only at receiver 4475. One tag, Tag ID # 821, was
detected only in Totten Inlet at receivers 3350 and 6798. The last detection from this tag was at
receiver 3350 on October 19, 2006.

Squaxin/Hope Island Sample Group
Eighteen cutthroat were tagged from the Squaxin Island and Hope Island vicinity on
September 9, 2006 and 16 (89%) were detected. Fourteen of the cutthroat detected (88%) were
detected by two or more receivers. One cutthroat, Tag ID #826, exhibited temporal and spatial
movement patterns that were not comparable of either sample group. This “outlier” individual
was not used in the analysis.
No data were recovered from receiver 2113 because the receiver was lost. Therefore,
there is not enough evidence to infer that cutthroat detected at receivers 6160 and 6154 at the
mouth of Hammersley Inlet actually entered or remained in the inlet because there was no
indication of movement into the inlet beyond the location of receiver 6154 and 6160. Cutthroat
detected could have simply been within detection range of receiver 6154 or 6160, but still within
open waters of Pickering Passage. However, for this analysis, tags detected at either Hammersley
receiver locations were considered to have utilized the inlet.
The Squaxin/Hope Island Sample Group utilized Totten, Little Skookum, Hammersley,
and Eld Inlets. Two (15%) utilized Eld inlet, six (46%) utilized Totten Inlet, four (31%) utilized
Little Skookum Inlet and/or Skookum Creek, and eleven (85%) utilized Hammersley Inlet. Two
(15%) were detected in Pickering Passage at receiver 4479 and one (8%) was detected in Peal
Passage at receiver 6158.

20

Of the cutthroat detected at two or more receivers 7 (54%) were detected in multiple
inlets and 5 (39%) were detected in only one inlet. One cutthroat, Tag ID# 483 did not utilize any
inlets, registering detections at receivers 6158 and 4479 in Peale and Pickering Passage. Of the
cutthroat that utilized multiple inlets, two (29%) were last detected in Eld Inlet, one (14%) was
last detected at Hammersley Inlet, two (29%) were last detected in Totten Inlet, and two (29%)
were last detected in Little Skookum Inlet/Skookum Creek. Four (80%) of the cutthroat detected
only in one inlet utilized Hammersley Inlet and the waters associated with receiver 3345 and one
utilized Totten-Little Skookum Inlets and the waters associated with receiver 3345.
Eleven (85%) of the cutthroat from this sample group utilized Hammersley Inlet, but only
five (46%) of these fish were last detected at Hammersley Inlet. Of the 11 cutthroat detected at
the Hammersley Inlet receivers, seven (64%) utilized other Inlets besides Hammersley and four
(36%) were not detected in any other inlet. Of the cutthroat detected in other Inlets, only one was
last detected at Hammersley Inlet.

Comparison between Sample Groups
Based on the timing of detections, it appeared all of the tagged cutthroat remained within
the confines of the study area (Figure 2) during the study. Twelve of the 13 cutthroat (92%)
detected at multiple receivers from the Totten-Little Skookum Inlets Sample Group remained
within the sample area. None of the cutthroat detected at multiple receivers from the
Squaxin/Hope Island Sample Group remained within the sample area.
Mean travel distance for the Totten-Little Skookum Inlets Sample Group was 11 km with
a maximum travel distance of 37 kilometers (km). Mean travel distance for the Squaxin/Hope
Island Sample Group was 17 km with a maximum travel distance of 53 km. Seventeen out of the
26 cutthroat (65%) detected at multiple receivers from across both sample groups crossed open
water (i.e. moved across inlets or passages).
Sixteen of the 26 cutthroat (62%) detected by two or more receivers (i.e. cutthroat that
utilized multiple habitats) were found to have utilized Skookum Inlet at some point during the
study. Frequency of Skookum Inlet utilization ranged from less than two days to over three
months.

Relationship of Movement Patterns to Size-Class of Cutthroat
Data analysis using a single factor ANOVA test showed a significant difference between
size class of cutthroat (≥200 to <300 mm; ≥300 to <400 mm; ≥400 mm), the distances traveled,
and the number of receivers the tags were detected (P<0.05). There was not an equal

21

representation of each size-class among or between the sample groups, which may have skewed
the analysis. Seventeen (63%) of the cutthroat detected were in size-class ≥300-<400 mm, eight
(30%) were ≥200-<300 mm, and two (7%) were ≥400 mm.

Relationship between Cutthroat Movement Patterns and Chum Run-timings
Run-timings were based on data provided by the Squaxin Island Tribe (Peters, Squaxin
Island Tribe pers comm). Juvenile out-migrations were estimates based on the escapement timing
provided by the Squaxin Island Tribe.
Over 92% of the cutthroat from the Totten-Little Skookum Inlets Sample Group
exhibited directional movements towards the extreme terminal areas and associated freshwater
habitats of Totten and Little Skookum Inlets during known chum run-timing. Over 60% of the
tagged cutthroat from this sample group exhibited directed movements towards the extreme
terminal areas either earlier than the known chum run-timing or during the earliest known runtiming.
At least 50% of the tagged cutthroat that entered Skookum Creek during the fall or winter
months (2006) and during known chum run-timing also exhibited movements out of Skookum
Creek into the marine habitat of Little Skookum Inlet in the spring, March-May 2007, during
known chum fry out-migrations.
Fifty percent of the Squaxin/Hope Island Sample Group exhibited movement patterns
that tracked chum run-timing and 50% of this sample group exhibited movement patterns that
either clearly did not reflect chum run-timings or, due to gaps in the data, were unknown. Of the
cutthroat that followed known chum run-timing, approximately 71% were associated with
Hammersley Inlet and 29% were associated with Totten-Little Skookum Inlets. None of the
cutthroat that followed known chum run-timing were associated with Eld Inlet, which has active
chum spawning in two terminal streams (Perry and McClane Creeks). Eighty percent of the
cutthroat last detected at receivers 6160 or 6154 at the mouth of Hammersley Inlet were detected
earlier than the known chum run-timing for either the Summer or Fall chum runs known to utilize
Hammersley Inlet.

Discussion

Movements of Sample Groups
Coastal Cutthroat detected at one receiver for long durations of up to three months may
have been an indication of territorial behavior or site fidelity (Goetz et al 2004). For example, Tag

22

ID #54 remained in close proximity to receiver 3345 for three months before making migrations
into Totten and Eld Inlets. Conversely, continuous detections observed at one receiver may have
been an indication of mortality (Goetz, University of Washington pers comm; Steltzner, Squaxin
Island Tribe pers comm.).
Some cutthroat registered detections at only one receiver, but for a few days. These types
of detections may have resulted from the randomization of pulse trains programmed for each tag
and cutthroat swimming speeds. There was also the likelihood fish swam past a receiver without
being detected (Goetz, University of Washington pers comm.; VEMCO 2007).
A cutthroat may have gone undetected by more than one receiver by utilizing habitats
outside the detection range of a receiver. For example, tag ID Code #3114 was only detected in
the first week of March at receiver 3371, which was located along the Southeast shoreline of
upper Totten Inlet. These “delayed” detections indicated that this fish had gone undetected for the
previous 6 months.

Depth Tag Readings
Data from the four depth tags detected indicated these cutthroat had a strong tendency to
remain closer to the surface during non-daylight hours than during daylight hours. Data indicating
that cutthroat were closer to the water surface during non-daylight hours could have been a result
of adjusting to shallower depths or simply utilizing shallower habitats (Figure 8). Thus the
recorded depths were not indicative of habitat, but merely the depth of the fish from the water
surface.

Figure 8: Visual representation of fish depth in relation to seafloor.
This figure illustrates the depth recorded for a fish is not indicative of the habitat it is occupying. In Both
diagrams the fish is at a depth of 2.0 m from the water surface. In the image on the right, the fish is at a
depth of 2.0m while occupying shallow habitat. The image on the left depicts a fish at the same depth, but
occupying a deep-water habitat.

The negative depth readings from freshwater receiver 7064 may have been caused by
various factors such as temperature because changes in temperature can affect the readings of the

23

tags (Webber, VEMCO pers comm). Smaller waterbodies and shallower depths, like those
observed in Skookum Creek at receiver 7064, are more susceptible to ambient temperature
changes than are larger and deeper waterbodies. Channel morphology may have also influenced
the depth readings, in that detections may have been skewed or interrupted by the structure of the
streambed. Narrow channels, organic material, and uneven terrain can all create interference with
acoustic signals (Fred Goetz, University of Washington pers comm).
Detections observed for Tag ID#54 and #56 indicated these cutthroat crossed open water.
Analysis of detections from Tag ID #54 indicated this cutthroat traveled distances of up to 14 km
within 25.5 hours. The detections observed for Tag ID #56 at receiver 7064 on December 18,
2006 and March 2, 2007 may indicate freshwater overwintering or spawning activities.
Totten-Little Skookum Inlets Sample Group
Data indicated that the Totten-Little Skookum Inlets Sample Group overwhelmingly
stayed within the sample area and for the most part did not utilize other inlets. There was no
conclusive evidence that the Totten and Little Skookum Inlet Subgroups behaved in the same way
that the Totten-Little Skookum Inlets Sample Group behaved.
The results of the Totten-Little Skookum Inlets Sample Group seem to indicate inlet
fidelity among this sample group during the fall and winter months. This behavior supports
current literature that anadromous cutthroat trout are divided into distinct populations, or stocks,
within the South Puget Sound ESU, at the stream or tributary level (Northcote 1997; Trotter
1989; Trotter 1997; Johnson et al 1999; Williams et al 1997). However, as shown in the
Squaxin/Hope Island Sample Group results one fish could utilize multiple inlets. Therefore inlet
fidelity may be applicable only during certain seasons or specific to certain behaviors such as
spawning.
Detections recorded at receiver 4475 and 7064 indicated a strong migratory link between
the extreme terminal area of Little Skookum Inlet and the freshwater habitat of Skookum Creek.
However, there was no definitive evidence to conclude that all tagged cutthroat utilizing the
freshwater habitat of Skookum Creek during the winter months also overwintered in this
freshwater habitat. Anomalies, gaps in the data, and inconsistent detections in freshwater from
multiple tags may indicate saltwater overwintering behavior by cutthroat. For example, Tag ID
#3119 registered detections at receiver 7064 on two days in November 2006, and on February 22
and March 2, 2007, but this fish was detected at multiple receivers in the marine water after the
detections were recorded at receiver 7064 in November. These detections indicated short-term
freshwater residency during the winter months.

24

Tag ID #3121 was detected at receiver 7064 in March 2007, but registered no detections
at this location during the winter months. These detections indicated this cutthroat could have
overwintered in saltwater. Detections may also reflect amphidromous behavior in relation to a
specific food source such as the downstream migration of chum fry in Totten-Little Skookum
Inlets during the spring months of March-April.

Squaxin/Hope Island Sample Group
The majority of cutthroat from the Squaxin/Hope Island Sample Group utilized the
habitat within 200-400 m of receivers 6154 and 6160 (located in Hammersley Inlet) at some point
during the study. Regardless of the duration or frequency of detections, no other inlet was so
heavily utilized by cutthroat from this sample group. Although the majority of the cutthroat from
this sample group utilized Hammersley Inlet at some point during the study, most did not commit
to one inlet over another and tended to “roam” between Hammersley, Totten, Little Skookum,
and Eld Inlets. Despite the lack of inlet preference, there was a trend in movement towards the
extreme terminal areas (inlets) of the study area, rather than to remain in the open waters of
Squaxin, Pickering, or Peal Passages.
Multiple cutthroat from this sample group were detected at receivers in marine waters
during the winter months, December 2006 – February 2007, indicating these cutthroat most likely
overwintered in marine waters. However, due to a lack of receivers in freshwater areas and the
coarse scale of the marine receiver network, no definitive conclusions could be drawn about
saltwater or freshwater overwintering behaviors for this sample group.

Comparison between Sample Groups
Analysis revealed a difference in movement patterns and distances traveled between
sample groups. There was a trend within the Totten-Little Skookum Inlets Sample Group to
display intentional or directed movements within the inlet with short overall travel distances.
The trends displayed among the Squaxin/Hope Island Sample Group were: 1) greater
accumulative travel distances and; 2) less discrete movements, or roaming travel patterns,
between inlets. Regardless of the distances traveled or the observed inlet preference of individual
cutthroat, the overall trend for both sample groups was a movement towards the extreme terminal
areas (inlets) of the study area, rather than to remain in the open waters of Squaxin, Pickering, or
Peal Passages.
The differences in observed movement patterns and travel distances may indicate
different life-history strategies among anadromous coastal cutthroat trout of South Puget Sound.

25

Some individuals may be closely associated with discrete habitats, while others may be more
pelagic, taking maximum advantage of food and habitat found throughout the study area. This
behavior may also simply support existing literature on the adaptability and opportunistic
behavior of coastal cutthroat trout in a shifting environment (Johnson et al 1999; Northcote 1997;
Trotter 1989; Trotter 1997).
Data indicating that none of the tagged cutthroat moved outside of the study area may
suggest that anadromous coastal cutthroat in South Puget Sound have a discrete home range
distinct from Central and North Puget Sound. This finding may also indicate that the coastal
cutthroat populations in South Puget Sound are distinct from Central and North Puget Sound
populations.
Contrary to current literature, data in this study indicated that cutthroat representative of
all size-classes sampled crossed open waters (Jones 1978; Trotter 1989; Trotter 1997); however,
tidal stage and time of day during which cutthroat crossed open water were unknown due to the
limited number and placement of receivers. Acoustic data collected from studies conducted on
anadromous coastal cutthroat trout in Hood Canal, Washington corroborated anadromous coastal
cutthroat do cross open waters of various depths and widths (Goetz, University of Washington
pers comm).
The Totten-Little Skookum Inlets Sample Group tended to stay “centralized” or within
the sample area for the duration of the study while the Squaxin/Hope Island Sample Group tended
to “roam” outside of the sample area, moving between inlets. This behavior may indicate that
overwintering anadromous coastal cutthroat prefer habitat types and conditions found in inlets
and the extreme terminal areas associated with these inlets over open water habitats.
Contrary to the more local movements observed for the Totten-Little Skookum Inlets
Sample Group, cutthroat sampled from the Squaxin/Hope Island Sample Area were not
specifically associated with one inlet over another inlet. This behavior may simply highlight that
cutthroat take advantage of food sources, refugia, or other conditions found in particular inlets
prior to committing to a specific inlet or associated freshwater habitats during the fall and winter
months. Utilization of multiple inlets may also indicate opportunistic strategies in habitat
selections based on food source, competition, or other environmental factors.
There was a noticeable similarity between the sample groups in the utilization of Little
Skookum Inlet. This finding may indicate a preferred or critical habitat for coastal cutthroat in
South Puget Sound during fall and winter months.

26

Relationship of Movement Patterns to Size-Class of Cutthroat
Both sample groups indicated a significant difference (P<0.05) in movements in relation
to size-class. Larger size-class of cutthroat had a tendency to travel farther distances than the
smaller size-classes. Also, the larger size-class of cutthroat tended to be detected at more
receivers than the smaller size-classes. These findings suggest larger cutthroat do not have
discrete territorial ranges and are opportunistic in their habitat utilization. Findings may also
indicate morphological constraints of smaller cutthroat to traveling long distances.

Relationship between Cutthroat Movement Patterns and Chum Run-Timings
It was unclear whether the movement patterns of the Totten-Little Skookum Inlets
Sample Group were in response to chum run-timing or a coincidence of shared habitat utilization
because the sample group overwhelmingly stayed within the sample area. However, analysis of
the Totten-Little Skookum Inlets Sample Group movement patterns indicated a positive
relationship between the directional movement patterns of cutthroat trout and run-timing for
chum salmon.
Data also indicated that the relationship between the Totten-Little Skookum Inlets
Sample Group movement patterns and chum run-timing may be an inherent behavior pattern of
cutthroat rather than a conditional response. Directional movement patterns of the tagged
cutthroat appeared to reflect proactive behavior to adult chum run-timing rather than a reactive
behavior to chum moving into the inlets/freshwater habitats.
In Totten-Little Skookum Inlets, chum salmon fry migrate out of freshwater habitats
primarily during March and April. These out-migrants then remain in relatively protected,
sheltered, and low-energy nearshore areas, such as the habitat found in Little Skookum Inlet, for
the first few months after migrating. This sample group of cutthroat indicated some individual
cutthroat may not only take advantage of a high protein food source by utilizing temporally
discrete adult chum runs but they may also utilize the chum fry life-history stages. When they are
present, chum salmon fry are an important food source for anadromous cutthroat (Jauquet 2002).
The detections observed at receiver 7064 in Skookum Creek and receiver 4475 in Little Skookum
Inlet during the spring months, and the known predator/prey interaction between species
indicated a positive relationship between anadromous cutthroat movement patterns and juvenile
chum salmon migrations.
Some cutthroat registered detections in salt water during the winter months, indicating
marine overwintering behavior, but also exhibited movement patterns reflective of both adult and
juvenile chum migrations. For example, Tag ID#3119 registered detections at the Skookum Creek

27

receiver (7064) during peak adult chum run-timing in November, 2006; and during chum fry outmigration in March, 2007. This tag was also detected at receiver 4475 in Little Skookum Inlet in
April 2007, approximately 11 days after being detected in Skookum Creek.
Of the tagged cutthroat from the Squaxin/Hope Island Sample Group, 50% exhibited
movements reflective of adult chum run-timing which suggests a proactive behavior to chum runtiming versus a reactive behavior. However, unlike the Totten-Little Skookum Inlets Sample
Group, the Squaxin/Hope Island Sample Group as a whole did not clearly exhibit directional
movement patterns relative to chum run-timing. Fifty percent of the tagged cutthroat from this
sample group did not exhibit movements reflective of chum-run timings or their movements were
unknown. Therefore, there was no strong indication of large-scale movements of coastal cutthroat
from broader and deeper-water areas into smaller, shallower, and more defined inlets in response
to temporally discrete chum salmon spawning migrations. Data did not support nor negate a
relationship between the Squaxin/Hope Island Sample Group movement patterns and chum fry
out-migrants.

Limitations

Several key limitations were identified in the results and discussion above. The following
is a more detailed record of the limitations encountered and recommendations for addressing
them in future studies.
One of the determining factors of receiver placement was assumed habitat utilization.
Receivers were placed in areas assumed to be utilized by cutthroat trout and would therefore be
ideal locations for capturing cutthroat movements; however, the areas identified were located
within nearshore areas. Consequently, this design did not allow for capturing movements in or
across open waters of the inlets or passages.
The influence of tidal cycles and diel patterns on cutthroat movements was a study
objective. While time of day and tidal cycle could be related to the time of detection, the distance
between receivers resulted in coarse resolution of the data, thus the relationship of these factors to
cutthroat movement patterns could not be analyzed.
The limited number of receivers in extreme terminal areas and associated fish-bearing
stream habitats led to inconclusive data on cutthroat overwintering habits and the inability to infer
directional moment of cutthroat once they entered the freshwater habitat. For example, it was not
possible to assess if tags detected at receiver 7064 in Skookum Creek remained in freshwater

28

during the winter months or if they utilized protected marine areas between receiver 4475 in
Little Skookum Inlet and the mouth of Skookum Creek.
A limited number of receivers within large areas caused some cutthroat to go undetected
for months at a time before being detected at a given receiver, making for difficult analysis of the
habitat types being utilized by cutthroat during fall and winter months. These apparent gaps in
detections may suggest critical habitats utilized by cutthroat that were not identified in the study
design.
There was insufficient data to adequately examine inlet fidelity among the tagged
cutthroat because of a lack of comparative data, the limited number of receivers, and the study
time frame.
Instrument limitations such as range detection of tags, collisions of multiple tags, and
memory capacity were known prior to the study, and are noted. Multiple tags from the
Squaxin/Hope Island Sample Group registered detections at receivers in terminal areas of an inlet
without being detected at receivers at the mouth of the inlet. Some tags were not detected for
months at a time. Missed detections may have been the result of the detection radius for the VR2
receivers, the tag delay time, or collisions (see Methods and Materials).
The high habitat use of Skookum Inlet by tagged cutthroat was not expected. This high
frequency of habitat utilization caused multiple collisions and the artifact of false detections.
Receiver 4475 in Skookum Inlet was filled to capacity before the end of the study. Both collisions
and memory storage capacity resulted in missed detections and data gaps.
During the study, receiver 2113 was lost, receiver 3347 was damaged, and receivers 4327
and 4205 were not retrieved due to environmental conditions (e.g. water clarity, storms), all
resulting in lost data. This loss affected the ability to determine directional and temporal
movements. The lack of data from either receiver 4327 or 4205 also reduced the size of the study
area and lessoned the ability to determine habitat use, if any, of Budd Inlet.

Recommendations for Future Research

Studying the behavior of a species about which little is known and tracking populations
within a large geographic range pose multiple challenges. Careful consideration should be given
to future research design when studying coastal cutthroat trout in their marine environment.
Restricting the study area to a smaller geographic scale and setting receivers in closer proximity
may help in closing gaps in data and improve understanding of directional and temporal
movements.

29

Longer study time frames and additional data such as, genetic sampling, multiple sample
groups from multiple inlets, and a larger network of receivers within inlets would be beneficial to
answer questions about population structure of anadromous cutthroat and distinct stocks within
the South Puget Sound ESU. Additionally, replicate sampling, sampling cutthroat from other
inlets, and sampling out-migrating cutthroat from freshwater systems would allow for in-depth
analysis of inlet fidelity among cutthroat populations in South Puget Sound.
Additional receivers in the extreme terminal areas of inlets and upstream in associated
freshwater habitats would help reduce the data gaps on coastal cutthroat overwintering behaviors
and clarify freshwater and saltwater habitat use during the fall and winter months. A network of
receivers, or “listening lines”, across inlets or passages would allow for analysis of tidal and diel
influence on cutthroat movements across open water.
To further investigate the relationship between anadromous cutthroat and adult chum
salmon run-timings, increasing sample size and the number of receivers would allow for more
complex analysis and reduce data gaps. Future studies might also sample outside the chum runtiming window to gather data on cutthroat movements before adult chum salmon begin their
migrations into a given inlet and the associated freshwater. This additional data may aid in
distinguishing between non-specific movement patterns and those relating to chum run-timing.
Future studies that identify high-use habitats, set longer delay times, and utilize higher
power tags would reduce the chance of missed detections. Downloading receivers at more
frequent intervals, using receivers with greater memory storage capacity, and checking equipment
function during the study will also reduce the chance of missed detections and help prevent data
loss. Creating an aggregate database with existing and ongoing acoustic studies would expand
analysis capabilities.

Management Implications

The existence of distinct populations among Pacific salmon species is an evolutionary
adaptation that has enabled populations to persist in shifting environments (Hendry et al 2004).
Data suggest distinct populations or stocks within the South Puget Sound ESU and these
collectively may be distinct from Central and North Puget Sound populations. Management
should take these possibilities into consideration when implementing policy directives. Adopting
a management approach that reflects the varied life-history strategies of anadromous coastal
cutthroat populations will help to maintain genetically robust and diverse populations of coastal
cutthroat in Washington.

30

Predator-prey interactions are essential to maintaining balance within any ecosystem.
These complex relationships are what drive the natural balance between population growth and
the carrying capacity of a given environment. Existing literature has established a predator-prey
relationship between anadromous coastal cutthroat and chum salmon in South Puget Sound, and
observations from this study support that relationship. To appropriately manage anadromous
coastal cutthroat and promote properly functioning estuarine ecosystems, the predator-prey
relationship between coastal cutthroat and chum salmon should be further examined.
Management strategies that support this relationship should be considered.
Nearshore habitat degradation, such as shoreline armoring and removal of vegetation for
development, is a threat to anadromous cutthroat populations. South Puget Sound is one of the
fastest growing areas in Washington State, and protection of critical estuarine habitats, like
Skookum Inlet, are essential to the continued existence of coastal cutthroat trout in this region.
Managers must begin to explore the role these habitats play in the perpetuation of anadromous
coastal cutthroat in South Puget Sound. By identifying how cutthroat utilize estuarine nearshore
habitats land management decisions and strategies to protect this subspecies can be appropriately
established.

31

Literature Cited

DNR (Washington State Department of Natural Resources). 1997. Final Habitat Conservation
Plan, September 1997. State of Washington Department of Natural Resources. Olympia,
Washington. p. III:55.
Ellings, C.S. 2003. The influence of spawning pacific salmon on the stable isotope composition,
feeding behavior, and caloric intake of coastal cutthroat trout. Master’s thesis. The Evergreen
State College, Olympia, Washington.
Federal Register, July 05, 2002, Vol. 67, No. 129. 2002. Endangered and threatened wildlife and
plants; withdrawal of proposed rule to list the southwestern Washington/Columbia River distinct
population segment of the coastal cutthroat trout as threatened; proposed rule. Department of the
Interior; Fish and Wildlife. p. 44934-44961.
Garrett, A.M. 1998. Interstream movements of coastal cutthroat trout (Oncorhynchus clarki
clarki) in the Clearwater River, Jefferson County, Washington. Master’s thesis. The Evergreen
State College, Olympia, Washington.
Goetz, F.A., E. Jeanes, E. Beamer. 2004. Bull trout in the nearshore-preliminary draft. U.S. Army
Corps of Engineers, Seattle District, WA.
Hendry, P.A., V. Castric, M.T. Kinnison, T.P. Quinn. The evolution of philopatry and dispersal
homing versus straying in salmonids. Pages 52-91 in A.P Hendry and S.C. Stearns editors,
Evolution illuminated: salmon and their relatives. Oxford University Press, New York.
Jauquet, J.M. 2002. Coastal cutthroat trout (Oncorhynchus clarki clarki) diet in South Puget
Sound, Washington 1999-2002. Master’s thesis. The Evergreen State College, Olympia,
Washington.
Johnson, O.W., M.H. Ruckelshaus, W.S. Grant, F.W. Waknitz, A.M. Garrett, G.J. Bryant, K.
Neely, and J.J. Hard. 1999. Status review of coastal cutthroat trout from Washington, Oregon,
and California. NOAA Technical Memorandum NMFS-NWFSC-37.
Jones, D.E. 1978. Life-history of sea-run cutthroat trout. Alaska Department of Fish and Game,
Anadromous Fish Studies, Completion Report 1971-1977. Projects AFS-42 (AFS-42-5-B):78105.
Northcote, T.G. 1997. Why sea-run? An exploration into migratory/residency spectrum of coastal
cutthroat trout. Pages 20-26 in J.D. Hall, P.A. Bisson, and R.E. Gresswell, editors, Sea-run
cutthroat trout: biology, management, and future conservation. Oregon Chapter, American
Fisheries Society, Corvallis.
ODFW (Oregon Department of Fish and Wildlife). 1997. Backgrounder: Oregon’s coastal
cutthroat trout. Retrieved January 30, 2005 from http://www.dfw.state.or.us/fish/
Pearcy, W.G. 1997. The sea-run and the sea. Pages 29-34 in J.D. Hall, P.A. Bisson, and R.E.
Gresswell, editors, Sea-run cutthroat trout: biology, management, and future conservation.
Oregon Chapter, American Fisheries Society, Corvallis.

32

Preikshot, D.; A. Beattie. 2001. Fishing for answers: analysis of ecosystem dynamics, trophic
shifts and salmonid population changes in Puget Sound, WA, 1970-1999
UBC Fisheries Centre Research Reports. Vol. 9:No. 6.
Trotter, P.C. 1989. Coastal cutthroat trout: a life-history compendium. Transactions of the
American Fisheries Society. 118: 463-473.
Trotter, P.C. 1997. Sea-run cutthroat trout: life-history profile. Pages 7-15 in J.D. Hall, P.A.
Bisson, and R.E. Gresswell, editors, Sea-run cutthroat trout: biology, management, and future
conservation. Oregon Chapter, American Fisheries Society, Corvallis.
USFWS (U.S. Fish and Wildlife Services). 1973. The Endangered Species Act of 1973.
USFWS (U.S. Fish and Wildlife Service). 2002. Columbia River Fisheries Program Office:
coastal cutthroat program. Retrieved January 30, 2005 from http://columbiariver.fws.gov/
USFWS (U.S. Fish and Wildlife Service). 2002. Coastal cutthroat trout population does not need
ESA protection. Dept. of the Interior, U.S. Fish and Wildlife Service, Portland, Oregon.
VEMCO. 2006. VEMCO VR2 receiver manual: operating manual; version 1.13. A division of
AMIRIX Systems, Inc.
VEMCO. 2007. Understanding the performance of VEMCO 69 kHz single frequency acoustic
telemetry. AMIRIX Systems, Inc. Technical White Paper doc #XDOC-004372 Version 04. May
3, 2007.
WDFW (Washington Department of Fish and Wildlife). 2000. 2000 Salmonid stock inventory:
coastal cutthroat volume Summary. Retrieved on January 30, 2005 from
http://wdfw.wa.gov/fish/sassi/cutthroat.htm
Welch, D.W., S.D Batten, B.R. Ward. 2001. Growth, survival, and tag retention of surgically
implanted acoustic tags in steelhead trout (O. mykiss).
Williams, T.H., K.P. Currens, N.E. Ward III, G.H. Reeves. 1997. Genetic population structure of
coastal cutthroat trout. Pages 16-17 in J.D. Hall, P.A. Bisson, and R.E. Gresswell, editors, Searun cutthroat trout: biology, management, and future conservation. Oregon Chapter, American
Fisheries Society, Corvallis.

33

Appendix 1: Angling Protocols

South Sound Coastal Cutthroat Acoustic Tracking Project; September 9 & 10, 2006
Angling Protocols
To minimize stress and mortality of cutthroat trout during sampling efforts the following steps
must be followed.
Gear Specifications:
• Single barbless hooks only
• Max hook size: #4 (although hook size should be relative to anticipated fish size!)
• Artificial lures only
• Landing nets used must be constructed of either rubber or soft, knotless mesh
Sampling Location:
• For both sampling days there will be a set sampling location that all anglers will be
restricted to. Maps will be distributed on sampling day.
Fish Handling:
• Keep fish in the water while removing hook and until ready to transfer to
transport/holding receptacle
• If fish is hooked deeply, cut the line as close as possible to the fish’s mouth. Do not
attempt to remove the hook. Once line is cut, fish should be safely released. It will not be
used in the sample.
• Once fish is removed from the water it will be put immediately into the transport/holding
receptacle.
• Seawater must be replaced regularly (and often) while fish are being held in transport
receptacle.
• No one fish will be held longer than 15 minutes in transport receptacle.
• Fish should only be handled by experienced anglers.
Additional Notes on Handling:
• Do not set fish on dry or hot surfaces while handling. Many surfaces, especially metal,
can become very hot in the sun. Fish skin is very prone to injury or burns and
skin injuries can decrease resistance to diseases.
• Avoid dropping fish onto the bottom of boats or other hard surfaces as this can cause
internal organ damage.
Imperative Sampling Actions:
• Minimize the time spent to land the fish. Long fights on light tackle unduly stress fish
and lead to lower chance of survival.
• If a fish caught is injured in any way (whether through angling or existing injuries) the
fish should be handled as little as possible and safely released. No surgeries will be
performed on injured fish.
• If a fish is hooked too deep and the line needs to be cut the fish must immediately be
safely released. No surgeries will be performed on these fish.
• Transport/holding receptacles will only be filled at the time a fish is captured.
Receptacles will never have standing water in them if they are not being used to hold and
transport fish.
• Fish caught must be brought to the surgery station within 15 minutes of capture where it
will be placed in a holding tank equipped with a circulating water supply and aerators.

34

Appendix 2: Sampling Data (page 1 of 3)

COASTAL CUTTHROAT ACOUSTIC TRACKING PROJECT: Sampling Data
Site: SQUAXIN AND HOPE ISLAND VICINITY
Date: SEPT 9, 2006
Wx: PARTLY CLOUDY, UPPER 60s - LOWER 70s (F)

High Tide
Stage (ft): 14.1
Time: 7:15am

Surgeon: SAYRE HODGSON (NISQUALLY TRIBE)_
Assistant: Sarah Haque

Low Tide:
Stage (ft): 1.2
Time: 1:39pm

Tag Serial #
P:0824
P:3114
P:3113
3139H
P:3112
3137H
5427H
5424H
5428H
P:0826
9861G
9850G
3140H
5425H
P:3116
9859G
P:0798
P:0820

Surgery
End
Time

Tag Code ID
824
3114
3113
56
3112
54
4088
4085
4089
826
483
472
57
4086
3116
481
798
820

11:40
12:10
13:10
14:30
14:45
15:00
15:15
15:35
15:40
16:05
16:40
16:55
17:15
17:25

Fork
Length
(mm)
360
210
220
350.5
275
440
310
300
410
340
260
315
450
310
270
270
315
340

Weight (g)
500
70
140
560
220
950
270
270
700
430
160
330
1010
350
210
200
360
460

Comments
SQUAXIN
HOPE
HOPE
HOPE
SQUAXIN
SQUAXIN
SQUAXIN
SQUAXIN
HOPE (Bleeder)
SQUAXIN
SQUAXIN
SQUAXIN
HOPE
HOPE
SQUAXIN
SQUAXIN
SQUAXIN
SQUAXIN

35

Appendix 2: Sampling Data (page 2 of 3)

COASTAL CUTTHROAT ACOUSTIC TRACKING PROJECT: Sampling Data
Site: TOTTEN AND SKOOKUM INLET
Date: SEPT 10, 2006
Wx: CLEAR, SUNNY, UPPER 70s - LOWER 80s (F)

High Tide
Stage (ft): 14.0
Time: 8:17am

Surgeon:_ SCOTT STELTZNER (SQUAXIN ISLAND TRIBE)
Assistant: Kyle Brakensiek, Sarah Haque

Low Tide:
Stage (ft): 2.8
Time: 2.:24pm

Tag
Code
ID

Surgery
End
Time

Fork
Length
(mm)

Weight
(g)

9857G

479

9:45

280

170

P:0827

827

9:55

250

130

3138H

55

11:08

400

670

P:0762
3136H
P:3127
5426H
P:3121
P:3122
P:3119
P:0795
9854G
9864G
P:3124
P:0821

762
53
3127
4087
3121
3122
3119
795
476
486
3124
821

11:22
11:27
11:45
11:58
12:08
12:14
12:20
12:30
12:52
13:00
14:10
14:35

300
360
370
310
380
330
340
330
270
240
340
290

280
450
460
300
460
320
420
380
180
140
330
230

Tag Serial #

Comments
SKOOKUM: NORTH
SHORE
SKOOKUM: NORTH
SHORE
SKOOKUM: NORTH
SHORE
SKOOKUM: NORTH
SHORE
TOTTEN: NORTH SHORE
TOTTEN: NORTH SHORE
TOTTEN: NORTH SHORE
TOTTEN: NORTH SHORE
TOTTEN: NORTH SHORE
TOTTEN: NORTH SHORE
TOTTEN: NORTH SHORE
TOTTEN: NORTH SHORE
TOTTEN: NORTH SHORE
SKOOKUM
TOTTEN: SOUTH SHORE

36

Appendix 2: Sampling Data (page 3 of 3)
P:0828
9855G
P:0819
P:3123
9865G

828
477
819
3123
487

14:40
16:20
16:30
16:45
16:55

330
240
300
340
200

420
130
240
430
50

P:3117

3117

17:20

320

320

SKOOKUM
TOTTEN: NORTH SHORE
(WINDY PT).

P:0775

775

18:00

410

670

SKOOKUM

SKOOKUM
SKOOKUM
SKOOKUM

37

Media

Haque_SRMESThesis2008.pdf