Tips for Making Your Observations
Look for Color Ranges
Because the Mearns Rock photos were taken at different times of day and under different weather and light conditions, they vary in their color and clarity. Watch for four color ranges to identify the marine life:
- Gray areas tend to be bare rock.
- Black areas are often mussels.
- Areas that range from green to gold to brown are often Fucus gardneri (rockweed or popweed). Young Fucus plants are more green in color, mature plants are more brown.
- White or light gray regions tend to be barnacles.
As you look through the photos, you will note that algae or seaweed sometimes cover much of the rock, possibly hiding barnacles and mussels from our view. Before making your estimates, first establish the criteria that you'll follow. For example, consider basing your observations on "what's visible" rather than on your best guess of what might be living underneath something else.
Something to Consider
As you look through these photos, consider the intense competition for space that exists among marine life forms in the intertidal region. For example, if sea otters clear mussels off a section of the rock, that opens space for barnacles, Fucus, or other organisms to "move in" to that space. You'll see several examples in these photos.