BIOLOGICAL POLLUTION - Marine Pollution: What Everyone Needs to Know - page 193

Figure 10.2 Comb jelly Mnemiopsis leidyi (photo from NOAA)
10.2) arrived in the Black Sea. Comb jellies, or ctenophores,
superficially resemble jellyfish but are biologically quite dif-
ferent. They do not sting, and belong to a different phylum
(Ctenophora), so are not really jellyfish. In its native Atlantic
estuaries, abundance is restricted by predators and parasites,
and it tolerates a wide range of temperature and salinity. It
reaches 10 cm in length and eats zooplankton, including fish
eggs and larvae. Populations can reach very high densities.
When it arrived, it rapidly took hold in the Black Sea. By 1989,
there were about a billion tons of them eating vast quantities
of fish eggs and larvae as well as the zooplankton that com-
mercially important fish feed on, leading to the collapse of fish
stocks and the ecosystem of the Black Sea, as documented by
T. Shiganova. Genetic analyses showed that they had come
from both the Gulf of Mexico (e.g., Florida) and the northern
part of the native range (e.g., Rhode Island). The high genetic
diversity in the Black Sea population indicates release of a
large number and multiple invasions, which is consistent with
ballast water transport and their extensive distribution in the
Atlantic. In a strange turn of events, in 1997, another comb jelly,