56 Nebraskaland • May 2021
MIXED BAG
Recently, Marimo moss balls, infested with zebra mussels,
were found being sold across the United States. These
moss balls are actually a type of green algae, formed into
a ball approximately 2-5 inches in diameter. They are used
to filter water and absorb pollutants in aquariums and are
often sold in pet and aquarium supply stores. The moss balls
were originally imported from the Ukraine before being
distributed across the U.S.
The first report of zebra mussels in moss balls came
from an employee at a pet store in Washington, and the
U.S. Fish and Wildlife Service is coordinating efforts across
the country to respond to the find. This undertaking has
involved federal and state agencies, including the Nebraska
Game and Parks Commission. To date, infested moss balls
have been found in at least 30 states, including Nebraska.
Nebraska Game and Parks staff inspected two Petco
locations in Lincoln and found zebra mussels present in
several moss balls. All Petco and PetSmart locations in
Nebraska were cooperative when asked by Game and Parks
to remove the product from their shelves.
The zebra mussel is one of the most destructive invasive
species in North
America. It is a
D-shaped clam,
with alternating
light and dark bands, about finger-nail size. Zebra mussels
filter large quantities of plankton from water, decreasing
the food supply for native species. Their dense colonies clog
water intakes for power and water plants, block water control
structures, and damage fishing and boating equipment.
Nebraska Game and Parks has provided the following
guidance for anyone who has purchased moss balls:
To prevent the spread of zebra mussels from aquariums,
moss balls should be removed, placed in a plastic bag, frozen
solid and then disposed of in the trash. All aquarium owners
should dispose of tank water away from water sources, such
as a stream, and instead dump water in grass or gravel. Don't
dump aquarium water down the drain as this can spread
zebra mussels to water bodies.
For questions and to report aquatic invasive sightings,
contact Game and Parks at npgc.ais@nebraska.gov or 402-
471-7602.
ZEBRA MUSSELS IN MOSS BALLS
By Julie Van Meter, State Entomologist
Nebraska Department of Agriculture
Zebra mussel found in a moss ball.
Photo: USGS, Public Domain
