Environmental Engineering Reference
In-Depth Information
female crabs may carry thousands to millions of eggs, and
after release of larvae new clutches may be fertilized by sperm
retained from an earlier mating. While ballast water exchange
can help to reduce marine invasions, it should not be the only
measure. Research is ongoing into methods of destroying
organisms in ballast water using sterilization, ozone, or heat
treatment. Another option is to build treatment plants in ports
that take ballast water from the ships and sterilize it before
releasing it or returning it to another ship. Implementation
of onshore treatment should be practical in busy ports that
receive high volumes of ballast water. This also would not take
care of the invertebrates cruising around in the mud on the
bottom of the ballast tanks.
To reduce the risk of new invaders, standards are being
proposed that establish upper concentration limits for organ-
isms in ballast discharge. Standards have been established
by the International Maritime Organization (IMO), the US
Coast Guard, the US Environmental Protection Agency, and
individual states in the United States. Australia, Canada, and
New Zealand have established ballast water regulations. The
IMO established discharge standards based on the number of
viable organisms per volume of ballast discharge for different
organism size classes. The EPA has developed more stringent
numeric standards limiting the release of organisms in ballast
water.
Education for aquarists, fishers, and others can go a long
way toward reducing the introduction and spread of new
invasive species. In some areas new techniques are being used
in the aquaculture industry to reduce the risk of invasion. For
example, farmed mussels can be manipulated to have addi-
tional sets of chromosomes, making them sterile and thereby
reducing the risk of wild populations establishing.
New technology can improve monitoring and control. The
International Union for the Conservation of Nature (IUCN)
Centre for Mediterranean Cooperation has released a new app
for smart phones to help managers of marine protected areas
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