BIOLOGICAL POLLUTION - Marine Pollution: What Everyone Needs to Know - page 204

for control and monitoring, with an ongoing annual surveil-
lance cost of $1.2 million until 2004. Application of coarse sea
salt was used with moderate success in Australia to eradicate
Caulerpa taxifolia. Croatia attempted eradication by cover-
ing the seaweed with plastic sheeting, which was reasonably
successful in a limited area. Eradication has also occurred in
South Australia and New South Wales, and manual removal
by scuba divers was successful in eradicating a small patch in
the French Mediterranean. However, these methods are very
resource intensive and if even a tiny piece is missed, the spe-
cies can easily recover.
Caulerpa sold in the aquarium trade has the potential to
invade US waters. Surveys of southern California aquarium
retail stores in 2000-2001 showed that 26 of 50 stores sold at least
one Caulerpa species, with seven stores selling C. taxifolia . In late
2001, California banned the importation, sale, or possession of
nine Caulerpa species. To determine the effectiveness of the ban,
Caulerpa availability at previously sampled stores in Southern
California was investigated four years after the ban. Of 43
stores, 23 still sold Caulerpa with four stores selling C. taxifolia,
suggesting that the ban has not been very effective and that the
aquarium trade is still a source for distributing Caulerpa .
What can be done after a species has become abundant?
It is extremely difficult to control a marine organism once it
is established. Many marsh restoration projects in the East
Coast of the United States involve the removal of Phragmites
and replanting of Spartina, which is very labor intensive and
expensive and may require numerous applications of toxic
herbicides. This type of restoration may also involve lowering
the marsh elevation to favor the growth of cordgrass. However,
such restored marshes may eventually become inundated
sooner by rising sea levels. In some cases, re-establishing nor-
mal tidal flow is sufficient for the Phragmites to decline and