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Peanut Butter and Jellyfish


All over the world, people have been witnessing gigantic blooms of tens of thousands of jellyfish where once there were only a few. Fishers find them clogging their nets and costing them dearly. In Japan, giant jellyfish capable of reaching six feet across even capsized a boat that tried to bring them aboard. Where are these stinging menaces coming from and why are they everywhere?

Jellyfish explosions are often triggered by overfishing of small fish, like sardines and anchovies, which compete with jellyfish for food. Jellyfish are also more tolerant of low oxygen conditions than fishes, and so can survive in polluted “dead zones.” What’s more, once they become super-abundant, they snack on the larvae (babies) of fish, keeping fish numbers down. The result is an ecological flip-flop that is hard to reverse. Not surprisingly there is concern that when a huge jellyfish population moves in—there goes the neighborhood!

So, are jellyfish a dead end in the food chain? Fortunately, not always. Off the coast of southwestern Africa, where jellyfish have replaced sardines, at least one fish benefits. The five-inch long bearded goby spends its day on the seafloor in the oxygen-depleted and toxic mud where most fish, including their predators, cannot survive. While there, they graze on worms and mats of bacteria, but they can’t digest their food because they shut down the water flow over their gills to keep from gett