Meeting Abstract

P3.85  Tuesday, Jan. 6  A comparison of genetic variation between populations of pocketbook and pimpleback mussels above and below the St. Croix Falls dam (Minnesota/Wisconsin, USA) SZUMOWSKI, Suzy C.*; BOYER, Sarah L.; HORNBACH, Daniel J.; HOVE, Mark C.; Macalester College; Macalester College; Macalester College; Macalester College sszumowski@macalester.edu

There are forty-eight species of mussels native to Minnesota, and more than half of them are listed as endangered, threatened, or of special concern. The St. Croix River is a superior habitat for mussels, likely due to relatively light human disturbance in the watershed, although since 1903 there has been a hydroelectric dam at St. Croix Falls. Because the life cycle of mussels involves a larval growth phase in which the mussels are dependent on fish hosts for transportation, this barrier could greatly affect mussel population structure. Both Lampsilis cardium and Quadrula pustulosa are known to have multiple fish hosts, primarily catfishes for Q. pustulosa and sunfishes and perches for L. cardium. It has been observed in previous studies that the mussel assemblages above and below the St. Croix Falls differ, and that this variability is not likely to be a result of variation in microhabitat factors, such as substrate composition and water velocity. To determine the extent to which mussel populations above and below the dam are isolated from one another, small tissue samples from the mantles of 20 L. cardium and 20 Q. pustulosa were collected at four locations; two above the dam and two below the dam. DNA was extracted from the tissue clippings and the mitochondrial gene ND1 was sequenced. Preliminary data indicate the percent of polymorphic sites to be 3.30% for L. cardium and 8.44% for Q. pustulosa. From 42 L. cardium samples, 19 different haplotypes were present, versus 27 haplotypes from 35 Q. pustulosa samples, indicating that for ND1 Q. pustulosa is more genetically diverse than L. cardium.