Biota of Lakes and Reservoirs - Hydro-Environmental Analysis: Freshwater Environments - page 439

TABLE 15.5
Selected Invasive Aquatic Species
Alligatorweed

Alternanthera
philoxeroides

South America First reported in

Alabama in 1897

Probably introduced
through ballast water

Brazilian waterweed Egeria densa South America 1893 Aquarium trade

Caulerpa,
Mediterranean clone

Caulerpa taxifolia Caribbean Sea;

Indian Ocean

2000 (irst
infestation)

Aquarium trade

Common reed Phragmites

australis

Native to the United
States, but the more
invasive strains
originated in Europe

Invasive European
strains introduced
during late 1800s

Possibly through ships'
ballast

Curly pondweed Potamogeton

crispus

Eurasia, Africa,
Australia

Mid-1800s Possibly imported as an

aquarium ornamental
or introduced
accidentally

Didymo Didymosphenia

geminate

Northern Europe
and northern
North America
(Vancouver Island)

Was present in
Canada in the late
1800s, but did not
begin to cause
problems until the
early 1990s

Exact pathway
unknown, but it
spreads easily through
contaminated boats
and ishing gear

Eurasian water
milfoil

Myriophyllum
spicatum

Eurasia Approx. 1900 Aquarium trade

Giant reed Arundo donax Thought to be native

to eastern Asia

Early 1800s Introduced for erosion

control

Giant salvinia Salvinia molesta Brazil 1990s Aquarium trade

Hydrilla Hydrilla

verticillata

Africa 1960 Aquarium trade

Melaleuca Melaleuca

quinquenervia

Australia Early 1900s Used as an ornamental

and for erosion control

Purple loosestrife Lythrum salicaria Eurasia Early 1800s Through ships' ballast

and as an ornamental

Water chestnut Trapa natans Eurasia Late 1800s Ornamental

Water hyacinth Eichhornia

crassipes

South America 1884 Ornamental

Water lettuce Pistia stratiotes Unknown First described in

Florida in 1765

Unknown

Water spinach Ipomoea aquatica Asia 1970s Escaped ornamental

Source: Data from USDA National Invasive Species Information Center, NISIC.

15.4.2 I nVaSIVe a nIMaL S pecIeS
15.4.2.1 Spiny Waterlea
The zooplankton spiny waterlea is a relatively recent invasive species, presently restricted primar-
ily to the Great Lakes region (Figure 15.26). They were irst discovered in Lake Huron in 1984 (Bur
et al. 1986) and by the end of the 1980s, they were reported in the remaining Great Lakes. Currently,
they are also found in a number of other lakes in the region.
The spiny waterlea have a single long tail with small spines along its length, hence its name
(Figure 15.27). They may reproduce rapidly, and are often seen in gelatinous globs that collect on
ishing lines, often clogging the eyelets of ishing rods, and on downrigger cables. They outcompete