A giant swarm of jellyfish was spotted off the coast of Haifa, with the mass of tentacled creatures causing the water to look speckled with white when viewed from above, Israel’s Nature and Parks Authority said Wednesday.
The authority published images of the swarm, spotted Tuesday, after many of the gelatinous sea-dwellers had already made landfall this summer and washed up on beaches all along Israel’s coast.
The Nature and Parks Authority said that human behavior was helping to increase the intensity of the jellyfish swarms.
“Many things that humans are doing are helping to propagate the jellyfish, including the digging of the Suez Canal, polluting the sea with sewage, climate change and harming jellyfish predators such as sunfish and sea turtles. This is another reason to preserve the sea,” the environmental body said in a statement.
Most of the jellyfish that visit Israel are migratory, invasive species that originated in the Indian Ocean and are thought to reach the eastern Mediterranean via the Suez Canal.
Jellyfish tentacles can sting and inject venom into humans, which usually results in mild to serious discomfort and, in rare cases, lead to extreme pain, or even death.
While jellyfish have swarmed to Israel’s Mediterranean coast for decades, scientists understand little about the rules according to which they live and move and find it difficult to predict when the swarms will appear, which specific species they will consist of, and how long they will stay.
Jellyfish are also a threat to Israel’s power supply as they get sucked into the country’s power stations, which use seawater for cooling.
In 2016, University of Haifa researchers looked at when a power station was most badly affected by the jellyfish and correlated it with the moon and water temperatures, concluding there was a link between the annual arrival of the sea creatures and the phase of the moon.
A Hebrew-language website exists for Israeli bathers seeking to avoid jellyfish.