The annual hordes of jellyfish that float along Israel’s coastline at this time of year are supersized this year, according to researchers at the University of Haifa’s Leon H. Charney School of Marine Sciences.
There is a “huge” swarm of jellyfish off the coast of Haifa and they are “larger than ever,” the university said in a statement Sunday. Its marine researchers have been studying the ecology and life cycle of the jellyfish.
“Overall, this is the summer bloom of jellyfish that we anticipate, but there’s a slight difference in the size of jellyfish — on average, they’re bigger this year than in other years,” Professor Dror Angel said in the statement.
Angel ruled out any connection between the global pandemic and the size of the jellyfish, saying their increased size was likely due to a wet winter.
“I don’t think the coronavirus has anything to do with the jellyfish,” Angel said. “We had a very rainy winter this year, and the runoff that reached the sea provided a lot of nutrients that contributed to the formation of the jellyfish bloom. The nutrients feed the algae; the algae bloom and are eaten by small plankton herbivores, and these are then eaten by the jellyfish.”
“We haven’t identified human-driven factors, like pollution, which could also be affecting the blooms, ” he noted. “At the moment, we think natural phenomena have more of an impact than human effects.”
Angel said that over the past decade “different, intriguing species keep appearing. Although we consider them new, it’s possible that they’ve been around and we just didn’t see them until they became more abundant. It seems that the more you look, the more you see.”
The larger-than-usual species flagged near Haifa appears to affect the rest of Israel’s coastline.
Most of the jellyfish that visit Israel are migratory, invasive species that originated in the Indian Ocean and that apparently reached 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.
The creatures are also a threat to Israel’s power supply as they get sucked into the country’s power stations, which uses sea water for cooling. Last Thursday thousands of jellyfish had to be cleaned out of the Ashkelon power station.
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.
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 species they will be and how long they will stay.
Israel’s beaches have remained open to bathers despite the rising number of virus cases.