Tips on taking temperature

Most modules require taking the temperature, so it is important to understand the standard procedure for doing this.
Temperature is very important to aquatic life. Most aquatic organisms are cold blooded, so their body temperatures are the same as the water temperature. table 1 describes the kinds of stream life at various temperatures. Water temperature increases when the sun shines directly on a stream. Shading from trees, water surface area and volume, turbidity, stream bed colour, and orientation to the sun all affect the amount of sunlight absorbed by water. Table 2 has photos showing how to (and how not to) take temperature.

Table 1
Optimal Stream Life At Various Temperatures
20-25 C warm lots of plant life; high fish disease risk; warm water fish (bass, carp, crappie, catfish, bluegill); caddisflies, dragonflies
13-20 C (cool) plant life; moderate fish disease risk; trout, salmon, sculpins; stoneflies, mayflies, caddisflies, water beetles, water striders
5-13 C (cold) plant life; low fish disease risk; trout, salmon, sculpins: stoneflies, mayflies, caddisflies

Table 2
Air Temperature
To take the air temperature, hang the thermometer on a branch over the stream. Leave it there for at least 2 minutes
Water Temperature
Set the thermometer in the flow, be sure the bulb is not resting on a rock. Bright flagging tape reduces the risk of stepping on it, or leaving it behind. Leave the thermometer in the water for at least 2 minutes, and try to read it while it is still in the water
DO NOT hold the thermometer by the bulb, as it will give you a false reading