Jellyfish Invasion

Last night there was a fascinating documentary on TV titled "Jellyfish Invasion". One of the segments featured the Nomura's Jellyfish, a huge jellyfish that has been invading the Sea of Japan. See some horrifying photos here. According to the documentary, Nomura's Jellyfish used to appear once every 40 years. Recently, however, they have become an annual occurance and this is a big problem for the Japanese fishing industry because instead of hauling in nets of fish, fishermen are catching loads of jellyfish, and the fish that accompany them have been stung by their tentacles so that they are too full of toxins for human consumption. A Japanese fisherman told the camera how he really hated these jellyfish.

What's caused this jellyfish invasion? Well, the documentary explains how jellyfish begin life as polyps lying dormant at the bottom of the sea. Whenever there is a change in the environment (e.g. influx of nutrients or change of temperature) the polyps blossom into billions of jellyfish thus causing an invasion. The problem is aggravated when fishermen start hacking up the hated jellyfish which causes them to release their eggs and sperm creating millions of polyps per hacked jellyfish.

Why are they happening so frequently now? It was postulated that increased pollution and run-off from human industry is one of the reasons as this creates ideal conditions for jellyfish blossoms. The appearance of Nomura's Jellyfish in the Sea of Japan could have been the result of blossoms from off Shanghai.

It is a horrible situation and we may see it get worse!