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Cook Inletkeeper
Salmon Stream
Monitoring Program
Temperature
Cook Inletkeeper and the Homer
Soil and Water Conservation District have collected baseline
water temperature data in lower Kenai Peninsula’s salmon streams
since 1998. Water temperature is one of the most significant
factors in the health of salmon ecosystems. Temperature affects
salmon egg and fry incubation, fish metabolism, resistance to
disease, and availability of oxygen and nutrients. Research has
shown that cold-water fish species cease to migrate or die
un-spawned if exposed to long periods of warmer than usual
temperatures.
Monitoring has revealed that summer temperatures
consistently exceed Alaska’s standards.
Temperatures above 13°C exceed Alaska’s standard for
egg and fry incubation;
temperatures
above 15°C exceed Alaska’s standard for migration
routes.
Water
temperatures have even been recorded above 20°C
which by State Standards “may not be exceeded.”
INLETKEEPER
STRATEGIES
In 2002, the Salmon Stream
Monitoring Program was redesigned to address water temperature
concerns. Temperature loggers (StowAway TidbiTs by Onset Corp.)
were deployed to collect data at 15-minute intervals to quantify
how many hours per day and how many days per season salmon
stream temperatures exceed state standards.
To determine the frequency and
duration of elevated temperatures, temperature loggers were
deployed in the lower reaches of the streams in the summers of
2002 and 2003. Data from these loggers suggest that water
temperatures exceeded 13°C more than 50 days during
2002 and more than 56 days in 2003. On the Anchor and Ninilchik
Rivers, the number of consecutive days with temperatures
consistently above 15°C is increasing and may
influence timing of migration to spawning grounds.
In 2004, twenty temperature
loggers were deployed across the four watersheds. Sites were
selected at major confluences to provide information about the
relative contribution each major tributary makes to overall
stream temperature. This effort revealed that high summer water
temperatures extend throughout the watersheds and is not just a
concern in the lower reaches.
Extensive historical data are
not available so there is no way to be certain if elevated
temperatures are typical in these streams or if they are
responding to climate change. However, a USGS report
(Kyle and Brabets, 2001)
suggests that the Ninilchik River is likely to see a 3°C
increase in coming years. This conclusion is based on a model
that uses air temperature to predict water temperature. In
response to this report, the Homer Soil and Water Conservation
District and Cook Inletkeeper collected air temperature data in
2005 at each water temperature logger site to develop a
regression model to see how much variance in stream temperature
can be explained by air temperature.
Results from the linear
regression analysis suggest a very tight relationship between
water and air temperatures collected in the lower Kenai
Peninsula’s salmon streams. The relationship between air and
water temperature is likely to differ from stream to stream due
to varying degrees of shading, differences in the sources of
water (groundwater, surface runoff) and elevation. Longitudinal
changes are expected but the degree of change will be due to
natural and/or human influences. The degree of change was
greatest in the Anchor River watershed. Monitoring has been
instrumental is identifying this temperature trend and
illustrates the need to consider implications of both climate
change and land use in our land and fish management decisions.
FUTURE WORK
To address temperature concerns
as well as turbidity and habitat-related issues, the Homer
District and Cook Inletkeeper have identified action steps to
manage, protect, restore and monitor watershed health to ensure
healthy salmon populations for future generations. Actions are
aimed at improving protection of stream-side vegetation,
wetlands, and instream flows; increasing fish passage to small
tributaries; and reducing anthropogenic sources of sediment.
Future work will focus on these actions steps which are outlined
in the
Anchor River
Watershed Action Plan,
Deep Creek Watershed
Action Plan, and the
Ninilchik River
Watershed Action Plan.
ADDITIONAL RESOURCES & LINKS
Kyle, R.E.,
and Brabets, T.P., 2001, Water Temperature of Streams in the
Cook Inlet Basin, Alaska, and Implications of Climate Change:
U.S. Geological Survey Water-Resources Investigations Report
01-4109, 24p.
http://ak.water.usgs.gov/Publications/Abstracts/2001.Abstracts/CIBwatertemp.htm
For more
information on StowAway’s TidbiT temperature datalogger, see:
http://www.onsetcomp.com/Products/Product_Pages/temperature_pages/stowaway_tidbit_logger.html
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