7790

• UCREFRP Catalog Number: 7790
• Author: Tyus, H. M., W. P. Dwyer and S. Whitmore.
• Title: Feasibility of Preventing Further Invasion of the Zebra Mussel into the Western United States.
• USFW Year: 1993.
• USFW - Doc Type: \
• Copyright Material: NO

WATER PATHWAYS AND VECTORS
~`~~~ater pathways have probably been the most common means of spreading the zebra mussel in the United States. The mussels
are spread downstream as the veligers drift with the current. Once suitable habitats are reached, they attach to solid substrate
such as rock, piers, or boats. In upstream invasions, the veligers must be aided by a vector, which may include boats and
barges, or other carriers by which the mussel veliger can undergo passive transport. In contrast to land pathways, which are most
likely to be in straight lines, water pathways are not. As indicated in Figure 4, only two major types of water pathways exist: direct
conveyance of zebra mussels in lakes and rivers (downstream travel) and indirect transport by vessel.
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Information on major river systems
in Europe which became infected with
the nonindigenous mussel has shown
that the mussel can be transported
great distances both upriver and
downriver within a short span of years.
Modes of its upstream transport are
generally not well understood, but
Carlton (1993) suggested that the zebra
mussel may be carried and transmitted
by a host of natural and man-influ-
enced means. All major rivers and
waterways entering and connecting the
western United States and eastern
infested areas should be considered
potential pathways (Figure 3). Major
waterways are identified in Figure 9.
F/GORE 9. MAJOR EAST-WEST R/VERB.