BIOLOGICAL POLLUTION - Marine Pollution: What Everyone Needs to Know - page 194

Beroe ovata , invaded the Black Sea. A larger species, it feeds on
M. leidyi and caused a dramatic fall in their number, helping
the ecosystem to recover. Growing populations of zooplank-
ton, phytoplankton, and fish have been seen. It is possible to
use Beroe ovata as a biological control for Mnemiopsis leidyi .
However, purposely using another alien species for control of
an invader should be a last resort, given that it carries its own
risks of becoming invasive too.
What are some invasive crabs and what harm do they do?
The green crab (Figure 10.3) ( Carcinus maenas ) is native to the
Atlantic coasts of Europe and Northern Africa, where it lives
on protected rocky shores, pebbly beaches, mud flats, and
tidal marshes. It thrives in a wide range of salinity and tem-
perature, and has invaded South Africa, Australia, and both
coasts of North America. Its larvae spend about two months
in the plankton, dispersing many miles along the coast. Then
they are swept by tides and currents into coastal waters and
Figure 10.3 Green crab Carcinus maenas (photo from Peddrick Weis)