Coho Life Cycle
Monitoring
Coos Watershed Association  186 N. 8th St., Coos Bay, OR 97420
http://www.cooswatershed.org  [email protected]  (541) 888-5922
Program:
Since 2004 the Coos Watershed Association (CoosWA) has
conducted a life cycle monitoring (LCM) project to study
coho salmon abundance, survival, life histories, and habitat
use in tide gated lowland streams. Palouse and Larson
Creeks were selected as initial study sites, but monitoring
effort was switched from Larson Creek to Willanch Creek in
2015. For many years, the focus of stream restoration has
been in the upper reaches of salmon bearing streams.
However, recent data from this project, as well as other
similar projects, have revealed that juvenile coho thrive in
tidal rearing habitat and exhibit temporal /spatial migration
throughout freshwater and estuarine habitat. Utilization of
tidal habitat for foraging and winter shelter is a previously
undervalued aspect of coho life histories that has been
inhibited by human activity such as channelization, tides
gates, and dike construction. Life cycle monitoring efforts
help highlight the critical importance of diverse habitat and
juvenile fish passage for recovering viable coho populations.
CoosWA’s LCM project uses 5 main methods to monitor
coho: spawning surveys, PIT tags, antenna arrays, rotary
screw traps, and seining.
Spawning Surveys
Spawning surveys are designed to track long-term trends in
population abundance and involve surveyors hiking
upstream to count live fish and corpses of spawned out
salmon. A scale sample is also taken from every 10th salmon
carcass and sent to the Oregon Department of Fish and
Wildlife (ODFW) to be analyzed. Surveys are conducted
every 10 days for the duration of the spawning season.
PIT Tags
PIT tags, or passive integrated transponders, are small
cylindrical chips, similar to the chips used in car key fobs,
which emit a unique identifying code when activated by the
electrical field of an antenna array. Tags are inserted into
the body cavity of young parr as they pass downstream
through the rotary screw trap on their way out to the ocean.
PIT tagging allows fish movement up/ down stream to be
recorded at antenna sites without having to physically
recapture fish, even years after they were initially tagged.
PIT tagging fish
Antenna Arrays
Antenna arrays are used to track migration of PIT tagged
salmon via radio frequency identification (RFID) telemetry
network. Two rectangular antenna circuits spanning the width
of the creek are set up approximately 3-4 yards apart from
each other. As a PIT tagged salmon passes through the
rectangular circuit, its ID, date, and time are logged. Using two
logged points directionality and velocity of the salmon can be
determined. There are currently antenna arrays in both
Palouse and Willanch Creeks.
Rotary Screw Traps
Rotary screw traps (RST) consist of two large pontoons
supporting a spinning screw drum that funnels fish into a
collection reservoir. Staff members check this reservoir, or “live
box” every day and PIT tag appropriately sized coho as they
migrate downstream. Screw traps are installed seasonally,
typically around early March, in both Palouse and Willanch
Creeks to capture this downstream migration.
Seining
Seining nets provide a random, mobile, and cost effective
trapping method off the shore of larger bodies of water or
across streams using two lateral nets. One end of the net is
dragged along the bottom of the stream while the top is
supported by floats, creating vertical net surface in the water
column that prevents fish from escaping. Seining is useful for
sampling larger stream segments and may be used to assess
size, abundance, and boost numbers of PIT tagged fish if RST
capture was insufficient.
Want to know more about these programs or how you can support your watershed? Shoot us an email at [email protected]!
Coho Life Cycle Monitoring
Page 2
Connectivity
Beginning in 1997, coho salmon life cycle monitoring (LCM)
efforts were implemented as part of the Oregon Plan for
Salmon and Watersheds by the Oregon Department of Fish
and Wildlife (ODFW) in 7 coastal subbasins on the Oregon
coast to monitor fish abundance and survival (Suring et al.
2012). LCM efforts conducted by CoosWA in the Palouse and
Willanch subbasins are intended to broaden the scope of the
Oregon Plan projects by including tide gated lowland
habitats that are not captured by other ODFW LCM sites
primarily located in upland settings. This is particularly
important given the extensive conversion of lowland habitat
for agriculture or other human use in the Coos River estuary.
The high degree of land development in lowland habitat
critical to juvenile survival means that finding ways to
connect local stakeholders, policy-makers, and scientists will
be critical for the recovery of coho in the Coos basin and
coastwide.
Coho life cycle diagram showing monitoring effort over the
course of the life cycle
Table 1. Annual LCM monitoring budget categorized by funding
source. Funding varies yearly due to equipment needs. *Award
may be monetary or in-kind. In-kind may include labor costs.
Funding Source
Approximate Annual
Award*
OWEB
$72,000
Nehalem Marine (equipment)
$12,000
Bonneville Envir. Foundation
$2,000
Oregon State University Fish
and Wildlife Dept.
Intern standing on screw trap
Logistics
CoosWA’s LCM efforts are primarily funded by the Oregon
Watershed Enhancement Board (OWEB), Bonneville
Environmental Fund, and Nehalem Marine. All survey data
relevant to this project is submitted to the ODFW Natural
Resources Information Management Program (NRIMP) and
annual updates are made available on the CoosWA
website. Over 50 seasonal interns from local colleges and
AmeriCorps members have provided essential survey and
sample effort, over 12,000 hours since 2012. Additionally,
accepting interns has helped solidify strong partnerships
with South Western Community College (SOCC) and the
Oregon Institute of Marine Biology (OIMB). Finally, staff
involved with the LCM project collaborate with ODFW, the
South Slough National Estuarine Research Reserve
(SSNERR), the Bureau of Land Management (BLM), and
OIMB to coordinate community events and share
resources related to monitoring and restoration.
$6,000
AmeriCorps (interns)
$13,00
BLM (equipment)
$12,000
CoosWA
$4,000
OIMB (interns)
$1,500
SOCC (interns)
$1,500
Total
$124,000
Ed Hughes
Monitoring Program Leader
Coos Watershed Association
186 N 8th St
PO Box 388
Coos Bay, OR 97420
Office: (541) 888-5922 ex. 304
[email protected]
Want to know more about these programs or how you can support your watershed? Shoot us an email at [email protected]!