Giant Jellyfish
Coastal Policy Course Interactive Exercise
(c)2001

Ben Raines in his article, Jellyfish Damage in Gulf is raising Concern About Aquatic Life (New York Times, October 3, 2000, Science Tuesday section) tells us that, "Swarms of jellyfish consumed so many fish eggs and larvae in the Gulf of Mexico this summer that some scientists are talking about the potential for serious future threats to commercial and recreational fisheries in the northern Gulf."

"The jellyfish, a native species and an invading one, he writes, "appeared in prime spawning areas just as breeding season for many of the Gulf's most important species kicked into high gear. According to the National Marine Fisheries Service, the number of jellyfish in the Gulf has been rising for at least 13 years, since scientists started studying their population."

Why are the jellyfish prospering? Marine scientists have found that the jellyfish are taking advantage of three major changes in their environment:

1. "thousands of oil rigs and artificial reefs established to attract game fish have greatly increased the breeding habitat for jellyfish, which need a hard surface for spawning.
2. nitrogen pollution from farm runoff and industrial sources feeds plankton blooms, providing extra food for jellyfish.
3. commercial fishermen in the Gulf take great numbers of menhaden, a soft finned, bony fish that competes with jellyfish for the plankton."

Moreover, Phyllorhiza punctata the Australian spotted jellyfish have made matters worse. These 25 pound giants are native to the Pacific but have been prospering in the Caribbean and have migrated to the Mississippi fish breeding area. These jellyfish apparently eat huge numbers of eggs and larvae of local fish species which are important to the Gulf commercial and sports fishing economy. This includes Spanish mackerel, speckled and white trout, menhaden, redfish as well as crabs.

Raines quotes Dr. Monty Graham of the Dauphin Island Sea Lab in Alabama who said that the Australian spotted jellyfish scour the ocean for all living things leaving the water "… almost devoid of living things."

Clearly this is an interesting and important issue in Coastal Policy.

• First, the ecological changes have resulted from human activity.
• Second, the environmental imbalance could profoundly affect the ecological diversity of the Gulf.
• Third, many economic activities vital to the jobs and prosperity of coastal areas (commercial fishing as well as all forms of tourism) are endangered. Although the article does not specifically refer to this, one can imagine that basketball-sized Australian jellyfish floating off beaches, swimming areas, diving and snorkeling sites, will quickly drive out visitors.

"You really have two problems in terms of commercially important.fish," said Harriet M. Perry, director of the fisheries section of the Gulf Coast Research Laboratory in Mississippi. "First the jellies are ingesting the larvae and eggs of the commercially important species and then the fish larvae must compete with these incredibly efficient jellies for the same food source."

Although the Australian giants are the most interesting phenomenon they are bapparently a relatively small threat compared with the "... monstrous numbers of native moon jellyfish offshore below Alabama, Mississippi and Louisiana in a huge swath roughly100 miles long and 30 miles wide. It is these jellyfish that worry Dr. Joanne Lyczkowski-Shultz, a larval specialist with the National Marine Fisheries Service."

Mr. Raines also reports that "Dr. Lyczkowski-Shultz said the long-term picture might be bleak especially if the jellyfish populations continued to grow at their current pace. 'I'm just dazed,' she said. 'This is pretty serious. It could be totally devastating.' "

This problem is interesting since it involves a complex convergence of human activity and natural evolution and adaptation. It is also a classic coastal zone case study because it has the potential of seriously impacting coastal zone economic activities and human use of coastal zones.

Reflective Exercise:

1. What are the major sources of this jellyfish problem?
2. How can we begin reversing the sources of jellyfish growth?
3. Who's responsibility is it to carry out coastal zone remediation and who should pay for fixing these problems?