Little is acutally known about the life histories of fresh water mussels. While they are known to be long-lived, scientists are still perfecting easy and reliable dating techniques. The most common form of dating mussels is to examine a cross-section of a shell and count the number of growth rings. Mussels are thought to have a slow growth period (much like a tree) which results in a series of annuli. However, recent studies have shown that mussels can create multiple annuli in a given year, thereby throwing off the aging technique.

Similarly, little is known about the growth of mussels. Do they grow faster when they are younger? Do they reach a maximum length? How much do they grow in a year?

These are all questions we sought to exaimne by experimenting with a labeling survey. By marking mussels, we can measure growth over longer time periods, and better asses these questions. This survey may also answer questions about movement and densities of mussel populations by examining where the mussels have moved over a long time period.

Methods...

This study was conducted on the south shore of Dry Lake, east of site 1. We erected a carin west of the first large cliff to mark our study site.

We collected 40 mussels at four different depths. The mussels were scrubbed, dried, and washed with ethanol. They were then labeled using epoxy cement and a labeling gun. The cement was allowed to dry for 1 min, then we put the mussel back in the water.

We then replaced the mussels at their respective depths. We set up a transect line starting 1m from the cairn, and extending perpendicular to the shore (straight down towards the bottom of the lake). We placed buoys at approximately 1m, 2m, 3m, and 4m.

At each depth site, we set up two adjacent quadrats with a Styrofoam buoy in the middle on the upper corners. Each 1m sq. quadrat had rocks piled at each corner so a 1m quadrat could be replaced there in the future. Four mussels were placed 5 cm from each corner of the quadrat, and 1 mussels was placed in the middle of each quadrat.

Labeling and measuring...

The labels were placed below the umbo. When the width measurement is taken, the top of the caliper should be at the tip of the umbo, and the caliper should be placed so it is right on the left edge of the label. Length and height are the longest length and height you can measure. This way, an accurate measurement of each mussels' growth can be recorded.

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