Jellyfish: A Thriving Species
Jellyfish are a fascinating and mysterious creature belonging to the phylum cnidaria. Lacking a brain, they rely on a central nervous system that has receptors, which are able to detect light, odor, and other responses. Though jellyfish lack complete control of their movement, they use their radial symmetry to detect food and danger at all angles as they range from shallow waters to depths below 12,000 feet. Jellyfish reproduce sexually, as the gonads of males release sperm, which is swept into the mouth of females, and warm climates are usually better suited for breeding.

As global warming causes ocean temperatures to rise and the pollution of ocean waters causes the rise of plankton, in addition to the overfishing of jellyfish predators, jellyfish have been “invading” the seas across the globe. Not only have scientists seen an increase in this species belonging to the phylum Cnidaria, but they have also seen a greater area covered with migration patterns. In Northern Ireland “a salmon farm lost its more than 100,000 fish to an attack by the mauve stinger, a jellyfish normally known for stinging bathers in warm Mediterranean waters” (Michael Casey, Boston Globe). Such problems are not isolated in the Northern Atlantic, but across the globe off the coasts of China, Korea and Japan. Fisherman have seen the Normura jellyfish, the worlds largest jellyfish growing up to a diameter of 2 meters and 450 pounds, decimate their catch. These gigantic jellyfish find themselves caught in the fisherman’s nets and either crush the fish sought after due to their immense size, or sting the fish until dead. These jellyfish invasions have “cost the industry up to 332 million a year” and have even put fisherman’s lives in danger as “jelly filled nets capsized a ten ton trawler off the east coast as the crew tried to pull them up” (Michael Casey, Boston Globe) however all of the fisherman were rescued.

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Casey, Michael. “Jellyfish thrive as seas warm, threatening fishing industry worldwide.” The Boston Globe. Proquest Direct Multidisciplinary. November 27, 2009. Viewed February 18, 2010.
South Carolina Department of Natural Resources, Sea Science. “An Information/Education Series from the Marine Resources Division: Jellyfish;” 2005. Viewed February 18th, 2010.