Jellyfish completely invade harbor in Istanbul, defying explanation

Jellyfish strike fear in the hearts of anyone who has ever been stung by one. They drift on the currents in oceans all around the world. In most cases they are difficult to see, or even completely invisible. Their transparent bodies make them a danger that cannot be seen until it is too late.

Jellyfish have tentacles that are equipped with barbs that fire upon contact with living creatures. These barbs inject a powerful toxin that can cause a severe burning sensation, rash and irritation, nausea, cramps, paralysis, and in some cases, death. Not all jellyfish cause such an intense reaction, but most are painful to some extent. These stings are used as a defence and also as a means of hunting for prey.

This harbour in the Bosporus River in Istanbul was filled with millions of jellyfish that drifted in with no explanation. Some were as small as silver dollars while others were as big as a dinner platter. Tourists and residents were baffled at the sight, as were the local scientists. Such a massive number in one place defied explanation.

One theory was that overfishing has depleted the mackerel and sprat fish populations, causing a decrease in predation on the jellyfish. The massive invasion could even be seen from the air.

Local fishermen complained that it was impossible to fish in the Bosporus River while the area was clogged with these creatures. Overfishing has also resulted in the death of many Delphinus dolphins, an endangered species. Whenever humans take an excessive number of one species out of the environment, the results are complex and disastrous. It will take decades for this balance to return, if it ever does.