The sediment confined nutrients can easily re-suspend in turbid/shallow areas and lead to phytoplankton/cyanobacteria blooms, an increased trophic state, and decreased water quality. Due to their incredible filtering capability, dreissenids can significantly increase water clarity. The increased water clarity can be misleading because zebra and quagga mussels are essentially concentrating the nutrients in the sediment or benthic regions. Not only do they destroy native mussel (Unionoida) populations, but they also effect water quality and lower trophic levels. They directly displace indigenous bivalve communities by outcompeting them for habitat and nutrients.
Threats and Impactsĭreissenids' filter-feeding life style and large populations of up 750,000 individuals per square meter can have many impacts on an aquatic ecosystem. However, their ecological requirements, like calcium concentration, could help keep zebra and quagga mussels from successfully establishing and becoming a nuisance in the some Adirondack waterways. Both of these species' life cycle, high fecundity, and microscopic veliger stage allow for easy dispersal and establishment within and between water bodies. Quagga mussels have yet to reach the inner boundaries of the Park but thrive in waters closely surrounding. Since the mid-1990s zebra mussels have been established on the edges of the Adirondack Park in Lake Champlain and Lake George. Lawrence River, the Mohawk and Hudson River drainages (Mills et al., 1996). Within a few years after initial colonization, the two have spread quickly throughout the Great Lakes, Finger Lakes, St.
As of 1991 the quagga mussel, native to the Dnieper River drainage of Ukraine, has been found in the Erie Canal and Lake Ontario. The zebra mussel is native to waterways of southern Russia, and has been established in North America at St. Native to parts of Europe, Zebra and Quagga mussels have been transported to the Great Lakes basin by ballast water discharge from transoceanic vessels. On the other hand quagga mussels are more associated with soft substrates and deeper, cooler waters (found at depths of 130m), but more frequently quagga mussels have been displacing zebra mussels from the rocky littoral zone within 4-12 years after their establishment. (2000) has found populations on softer strata (sand, silt, mud) adjacent to the original hard strata colony. However ten years after the initial colonization of zebra mussels, Berkman et al. Zebra mussels are most notably associated with a firm attachment to hard substrates because their D-shape and byssal threads. polymorpha and D.bugensis for the most part occupy two different niches, which allow them to initially coexist at depths from 8-110 meters. Both species have two major life stages: planktonic larval and sessile, dioecious adult. polymorpha and D.bugensis are analogous, varying with size and time in the specific developmental phases. Simply if a quagga mussel is placed on their ventral side they would topple over whereas a zebra mussel would remain upright on its ventral side.Īdditionally the life cycle of the D. A quagga mussel's ventral side is convex with the ventral lateral margin lacking an acute angle while a zebra mussel's ventral side is typically flattened with an acute lateral-ventral angle. Anatomically they share shell coloration (black, white, or both), striation, and size (2.3-2.5cm) but have differing shell shape. However, genetic analysis has determined them to be two distinct species. Zebra and quagga mussels are bivalve, filter feeders that negatively affect water related economies and can wreak havoc on aquatic ecosystems. They very similar species that were once considered the same. Zebra Mussels (Dreissena polymorpha) and Quagga Mussels (Dreissena bugensis) Description