Field Procedures

-In this survey quadrats constructed from PVC piping were used to limit searches. (Quadrats were 1 m2 and joined together in a grouping of four, allowing divers to search 4 meter2 at each location)

-Survey sites in each area the Cannon River were found using a Bushnell laser sighter and marked with flags.

- Upon reaching a given site via a flat-bottom work boat, anchor was dropped and search preparations were made.

-The temperature of air and the water were measured.

-Two divers wearing SCUBA gear entered the water, placing the quadrats on the substrate of the river.

-The quadrats were stabilized at the corners by small mushroom anchors; in areas of rapid current, anchors with ropes were dropped in front of the quadrats to support the divers while searching.

-Divers throughly searched all 4 m2 quadrats by hand and sight. Any mussels found were removed from the sediment.

-Specimens were put in mesh bags and given to a worker in the boat who quickly measured the mussels and returned them to the divers.

-Mussels were replanted in their quadrat of origen by inserting them in the substrate with the umbo facing downstream and the siphons up.

Note: Permits are required for this type of survey work. Ours was acquired from the Minnesota DNR through Bonita Eliason

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