The Jellies are Coming

An article on Yahoo (via the AP) yesterday attempted to tie the global explosion of jellyfish populations to global warming. While I believe that is probably one of the causes of this weird and disturbing trend, I think blaming it on global warming is way off base. Fishermen in Japan are complaining about jellyfish clogging their fishing nets, and whine that the government should do something about the jellyfish. This might stop the jellies: ban all fishing altogether! Those jellyfish are everywhere because people have fished out their predators and disrupted their ecosystems to favor them! From the article:

The gelatinous seaborne creatures are blamed for decimating fishing industries in the Bering and Black seas, forcing the shutdown of seaside power and desalination plants in Japan, the Middle East and Africa, and terrorizing beachgoers worldwide, the U.S. National Science Foundation says.

While I am tempted to celebrate the decimation of those fishing industries, I realize that it is not a good thing unless those fisheries recover and all those former fishermen never come back. I am upset that this article seems to raise concern for the well-being of these fishermen and climate change, rather than the more alarming issue to me: we have drastically changed the oceans’ ecosystems! Boo-hoo, there is less sushi to eat. The real tragedy is that there are so few fish out there now because of modern fishing. This problem will keep getting worse as long as we plunder ocean life gold-rush style. Also, don’t forget that jellyfish love the hypoxic dead-zones where algal blooms choke off almost all other life, like the one at the mouth of the Mississippi in the Gulf of Mexico. These dead-zones are caused by all the accumulated agricultural runoff that flow down rivers (fertilizer, cow and pig manure, pesticides, herbicides) and eventually into the Mississippi and the gulf.

They do mention these things, by the way, but only as an aside:

Increasingly polluted waters — off China, for example — boost growth of the microscopic plankton that “jellies” feed upon, while overfishing has eliminated many of the jellyfish’s predators and cut down on competitors for plankton feed.

You want fewer jellyfish? Go vegan, buy organic, leave the oceans alone.

When Jellyfish Rule the World

Photo credit: Yomiuri Shibun/AFP/Getty Images

That’s a real jellyfish. What’s scary is that jellyfish of all kinds are taking over parts of the world’s oceans. The combining factors of overfishing, coastal pollution, and global warming are creating a nice ocean world for jellies. Their  populations are exploding in recent years, and they are migrating closer to coastal areas.

The planet’s seemingly insatiable appetite for seafood is removing the jellies’ predators (fish!) from the ecosystem, allowing them to increase their populations. As waters get warmer, they migrate closer to land, which they love because they feed on the fruits of our pollution. From Discovery News:

The combination of overfishing and high levels of nutrients in the water has been linked to jellyfish blooms. Nitrogen and phosphorous in run-off cause red phytoplankton blooms, which create low-oxygen dead zones where jellyfish survive, but fish can’t, researchers said.

Yep. Dead zones. I guess a few odd people out there actually like eating jellyfish. But unless jellies become favored over other fish, we can expect this trend to continue. Left unchecked, the seas will become so overfished that seafood lovers will have little choice. Jellies, jellies everywhere!

Another link here about our future jelly overlords (at LiveScience).