Is It Hot Stuff?
Know Before
Stream temperature plays a very important role in the health and survival of Brook Trout. Record the temperature for 3 different locations within the stream and compare to the required temperatures for Brook Trout survival.
Get Out The Door
Assess how water temperatures in Twelve Mile Creek may impact Brook Trout health and survival.
Summer: Consistently cool water temperatures are critical to Brook Trout health and survival. The fish will die if water temperatures exceed 22 degrees Celsius for more than several consecutive days.
Fall: Brook Trout select to spawn near cool groundwater upwellings. With elevated temperatures females may choose to delay laying their eggs and can abandon spawning for the year if the temperatures are not suitable within a couple of weeks.
Winter: Protected from freezing air temperatures, groundwater temperatures remain consistent and continually feed into 12 Mile Creek.
Spring: Growth and development of newly hatched alevins can be slowed if water temperatures are high.
Using a pool thermometer, record the stream temperature in several places along the creek. When measuring temperature, hold the thermometer submerged below the surface and take the reading while the sensor remains underwater.
Record temperature, GPS coordinates or what3words location, and provide a brief description of the sampling location.
Compare recorded temperatures with the ranges below to assess how Brook Trout might be impacted.
6°C Lower range of groundwater temperature Brook Trout can survive
17°C - 19° Ideal water temperature for Brook Trout
20°C Brook Trout become stressed and experience delays in development
22°C Lethal to Brook Trout if sustained for several days
Think Some More
Did any of the results indicate temperatures higher than 19°C?
What portion of the lifecycle of the Brook Trout could be affected?
In this location, what are possible causes for heightened water temperatures? What could be happening upstream?
How could you determine the location of a groundwater upwelling within the stream?
Bring Along
water thermometer
GPS or what3words app
pencil and paper