Over the last century, due to increased fishing pressure,
anthropogenic eutrophication and global warming,
many marine zooplankton communities have changed
toward increasing dominance of harmful gelatinous
species (Hays et al., 2005; Dybas, 2006). Elevated populations
of gelatinous species in their native habitats
affect local ecosystems, but also raise the potential for
spread to other areas either by natural expansions
(Malej and Malej, 2004) or with ballast water (Dumont
et al., 2004).