An Analysis of Factors Potentially Limiting the Abundance of the Zebra Mussel (Dreissena polymorpha) in Salmon Creek, Monroe County, New York

Abstract

First reported in the Great Lakes basin in 1988, the zebra mussel (Dreissena polymorpha) has spread throughout the Great Lakes and central U.S. With a direct connection to Lake Erie, the New York State Erie Barge Canal was colonized by zebra mussels as early as the spring of 1989. Salmon Creek flows northeast from southern Monroe County to Braddock Bay, and Erie Barge Canal water is used to supplement creek flows north of the canal. At the beginning of the canal outfall channel to the creek is a dense bed of zebra mussels which has existed since at least 1990. After the outfall channel merges with the creek, within 75 meters downstream adult densities drop to less than one mussel per square meter. In the summer of 1993 veliger counts in the canal were on average 52 times greater than they were in Salmon Creek. Water quality in the creek and the canal were similar. pH ranged from 7.5 to 8.2 in Salmon Creek and from 7.3 to 8.3 in the canal, both well within the established range of zebra mussels. Temperature in Salmon Creek did not exceed 30°C, the maximum tolerated by zebra mussels, and calcium concentrations did not fall below 40ppm, the minimum tolerated by zebra mussels. Particulate organic carbon in the creek (21. 6 ± 1.8 ppm) did not differ from that in the canal (21.5 ± 2.3 ppm). Current in the creek (0.03 - 0.16 m/sec) did not exceed ranges that impair zebra mussel settling and growth. Given these appropriate physical habitat and water quality conditions and an abundant source of veligers, the factors limiting zebra mussel colonization in Salmon Creek appear to be 1) detention of zebra mussels by the wetland through which the canal discharge flows, 2) filtering of phytoplankton and veligers by the dense bed of adult zebra mussel at the beginning of the canal outfall channel, or 3) inappropriate food quality in the creek.