Are our oceans to be taken over by jellyfish?

This is one of a growing list of scare stories being perpetuated by the marine eco-alarmist industry and unsuspecting and gullible media people to fan the flames of the anti-fishing movement. While it's been around for years, it was most recently brought to the fore in Oceans of Abundance (link), a severely biased report resulting from the deliberations of a working group convened by Environmental Defense (at least $34 million from the "Big Four" foundations - link), Marine Conservation Biology Institute (at least $2 million ditto) and World Wildlife Fund (at least $9 million ditto). "Generous support (for the working group) was provided by the Walton Family Foundation."

In the Washington Post on May 6, 2002 (link), UBC researcher (recipient of at least $17 million from the "Big Four" foundations)  Daniel Pauly (link) was quoted "If overfishing continues in the North Atlantic and elsewhere, fishing boats could soon be chasing jellyfish instead of fish."

The article then went on:

But overfishing isn't the only explanation for rapidly expanding jellyfish populations, said scientist Monty Graham of the Dauphin Island Sea Lab in Alabama. "Ecosystems in which there are high levels of nutrients as a result of agricultural run-off, for example, provide nourishment for the small organisms on which jellyfish feed. In waters where there is eutrophication [over-fertilization], low oxygen levels often result, favoring jellyfish as they thrive in less oxygen-rich water than fish can tolerate. The fact that jellyfish are increasing is a symptom of something happening in the ecosystem."

Graham cited the northern Gulf of Mexico, in which all species of jellyfish are rapidly increasing. Moon jellyfish, for example, are being found in dense concentrations in offshore areas that overlap with prime fishing grounds, such as those for red snapper. "Moon jellies have formed a kind of gelatinous net that stretches from end to end across the gulf," said Graham. "How much impact they will have on red snapper and other fisheries is a big concern."

In the Adriatic Sea, a "bloom" of a jellyfish called Pelagia nearly shut down the ecosystem. "Huge quantities of jellyfish clogged all nets in almost no time," said scientist Ferdinando Boero of the University of Lecce in Italy. The Pelagia population has returned to normal, but the main cause - nutrient pollution - "could result in another such bloom at any time. Industrial, agricultural, and urban activities lead to enormous nutrient overloads discharged into the Adriatic Sea by the Po River," said Boero.

As far as could be determined, neither Monty Graham nor the Dauphin Island Sea Lab has taken any grant money from the "Big Four" foundations.