Every winter, a strange crowd gathers in the sea near the city of Hadera. Dozens of large sharks swim slowly in the shallow water, only a few meters from the shore. For years, local fishermen and swimmers knew about them, but only recently have scientists begun to study this unusual phenomenon seriously.
The sharks are mostly dusky sharks and sandbar sharks, two species that can grow to around three meters long. They appear from late autumn until spring, and they choose a very specific spot: the warm water that flows out of the Orot Rabin power station. The power station uses seawater to cool its machines and then returns it to the sea several degrees warmer. In winter, when the Mediterranean is cold, this warm water seems to attract the sharks.
Researchers from the University of Haifa have been tagging some of the sharks with small electronic transmitters. These devices allow them to follow the animals' movements. The results suggest that many of the sharks return to Hadera year after year, and that they travel long distances when they leave.
The sharks have become a tourist attraction. On calm days, crowds of people stand on the beach and watch the fins cutting through the water. Some visitors even enter the sea to swim near them. Experts warn that this is a dangerous idea. Although these sharks are not known for attacking humans, they are wild animals, and in 2023 a man who swam close to them was killed. Swimming near the sharks is now prohibited.
The story of the Hadera sharks also raises bigger questions. Both species are considered endangered, partly because of overfishing. Some scientists worry that the sharks have become dependent on an artificial heat source, which could disappear if the power station changes the way it works. Others see the site as a rare natural laboratory where we can learn how to protect these misunderstood animals.