While Israeli drivers sit in traffic jams, Israeli sharks have a clear run for their 30-mile daily commute along the shores of Hadera and Ashdod, researchers have shown.
University of Haifa marine ecologists who tagged 62 sandbar and dusky sharks have described the way they migrate from human-altered habitats along the Israeli coast.
The scientists risked a nip to take fin-clip, muscle and blood samples to understand the sharks’ biology, as well as monitoring their movement through satellite tagging and acoustic telemetry.
Lab manager Eyal Bigal said it was surprising to have such a high number of sharks in the area, considering that the waters off the Israeli coast were less productive than almost any other marine environment, making it the desert of the oceans.
“This doesn’t happen anywhere else,” Bigal said. “There’s something about this water off Israel’s coast that attracts apex predators that are, in the case of sharks, already endangered in the Mediterranean Sea.
“Here, we see large numbers of sharks in human-altered habitats like power stations, gas platforms, and fish cages. They’re not anywhere in the open sea.”
Describing the sharks’ seasonal movements, he said, “For some of the sharks that we tagged in Hadera, on the same day they leave that city they go to the other hotspot in Ashdod, even if it’s quite far away.
“A few of our sharks disappeared from Hadera and on the same day they showed up at the fish cages in Ashdod, just a few hours later. Then they stayed there for a few months and moved back to Hadera, so they hopped between hotspots. And the same sharks are coming back every year.”
Researchers initially thought the sharks stayed in Hadera from December to March, but now know that they stay along Israel’s shores until June. Bigal said that although the numbers of sandbar and dusky sharks were up, for unknown reasons others such as blue sharks, mako sharks and thresher sharks were down.