View - ResearchGate

Biological Invasions by Marine Jellyfish 243
punctata to the shrimp industry – for Mississippi alone, these have been estimated
to be US$ 10 million for 2000 (Graham et al. 2003, and references
therein).
14.3.2 Cassiopea andromeda (Scyphozoa)
The ‘upside-down’ jellyfishes (Cassiopea spp.) are common in tropical to subtropical
shallow water ecosystems such as mangroves, in both the Atlantic and
Pacific, and including the Indo-Pacific. While the medusa stage is capable of
swimming, it is best described as sedentary, with the algal symbiont-containing
oral mass oriented upward (i.e., bell pointing downward). Large dispersal
distances by this medusa are not realistic, lending further credence to the
probability that invasive scyphozoan populations are spread during the polypoid
stage. While human health, fisheries, or other commercial impacts are
not documented in assessments of either indigenous or invasive populations
(Spanier 1989; Holland et al. 2004), the sedentary nature of Cassiopea spp.
medusae allows us to gain some insight into possible human-mediated spread
of other problematic jellyfish.
The systematics of Cassiopea, similarly to that of other jellyfish, is complicated
by historical introductions. Holland et al. (2004) derived a global molecular
phylogeny of Cassiopea spp., in an attempt to gain historical clarity on
the putative C. andromeda invasion of the Hawaiian islands. Using mitochondrial
sequence information (cytochrome c oxidase I), they resolved six
species based upon reasonable genetic divergence. Moreover, they proposed
that the invasive population of Hawaiian C. andromeda represents two separate
invasion events, one from the Indo-Pacific, the other from the Atlantic.
Holland et al. (2004) suspected that the Indo-Pacific invasion was due to US
naval ships during World War II. However, ship activity between the Hawaiian
islands and the western Indo-Pacific was also heavy in the decades prior to the
war.
Another invasion of C. andromeda into the Mediterranean Sea is perhaps
the only instance of a ‘smoking gun’ where the actual invasion event has been
observed. Galil et al. (1990) reviewed several early publications not readily
available, but descriptive nonetheless of a sequence of interesting events. The
first was the observation of ‘large numbers’ of C. andromeda within the Suez
Canal itself near Toussuom south of Lake Timsah in 1886, only 17 years after
completion of the canal (Keller 1888, as referenced in Galil et al. 1990). This
was followed 15 years later by the first documented report of C. andromeda in
the Mediterranean along the coast of Cyprus (Maas 1903, as referenced in
Galil et al. 1990).