AS IT HAPPENS, we bump into some guys sending up a drone once we’re out of the water. “So you’re that German journo who’s interviewing me later today?” says Eyal Bigal, looking at my camera and catching me off-guard.
The 32-year-old ex-army diver is halfway through his PhD on “Biomass of Apex Predatory Megafauna in the Pelagic Habitat of the Easternmost Mediterranean Sea”, and is also manager of the Marine Top Predator Laboratory at the Morris Kahn Marine Research Station.
“We’re doing an aerial survey to record the numbers of sharks today,” he says, pointing at the sharks’ shadows on the remote’s display, “but we also observe their behaviour towards divers.”
Later at the field station, an impressive facility of Haifa University dedicated to the country’s marine megafauna, its array of research tools leaves me speechless (and sorry for European field stations).
There are acoustic, satellite and spaghetti tags, acoustic receivers, syringes to take blood and DNA samples, devices to implant chips on the animals and latest-generation drones developed in collaboration with the marine-technology department.
All these are means of tackling major questions about the aggregation of dozens of specimens of a shark species that is cursed with the Mediterranean conservation status “Data Deficient”.
Some dusky sharks are huge females up to 3.8m long and more than 20 years old. Given their scarcity in the Med, it’s not surprising that they are the subject of major studies.
Where do these sharks come from in early December, and where do they leave for in late March? And why exactly are they coming?
It could be the high water temperature helping the sharks through the winter months, the stream serving as a kind of stimulant sending plentiful oxygen from their gills straight to their bloodstream, or the availability of food. At this stage, everything is still possible and open to debate.
“We have a lot of questions and not many answers, but our tagging campaigns will hopefully bring results,” Bigal tells me. In 2017 up to mid-February this year six sandbar sharks up to 1.8m and 25 female dusky sharks up to 4m were tagged. So the sharks are essentially females, but whether they’re gestating or not remains unclear, and as yet there is no indication of a dusky shark nursery in Israeli waters.
“That’s just one of the open questions, but there are even more basic ones, such as how an environment so poor in nutrition and food sources can sustain pretty good numbers of apex predators,” says Bigal.
His colleague Adi Barash from Haifa University was the first scientist to undertake research on these sharks, and from interviews with local fishermen she found that shark and ray populations were rising, while numbers of bony fishes were decreasing.
Thirty years ago, fishermen hardly observed any sharks in the area around the powerplant, but these days divers and spearfishers are reporting more sightings there and elsewhere in the country.
Sandbar sharks used to dominate the waters around the Hadera powerplant until two years ago, when the larger dusky sharks took over. Unlike the hammerheads that used to be observed there but now seem to be mostly gone, the sandbars stayed even though they were no longer the dominant species.
Barash’s curiosity revealed a real sensation: comparisons of DNA structures of local dusky sharks with their Atlantic and Indo-Pacific cousins suggests that there must have been cross-breeding between their Mediterranean ancestors and immigrants from the Red Sea, leading to an extended gene pool.
Back in 2016, Barash was co-developing a management plan to further the protection of sharks and rays through stricter law enforcement, improved legislation and habitat protection.
“People used to come with trucks to catch them and sell them in Gaza, but even hundreds of sharks caught could not destabilise the stocks, so our little reserve could keep the species from disappearing in the Mediterranean,” she told me.
She has started a Facebook group called Sharks in Israel. “We yell shark, shark, shark until people get bored and ignore it!” the 40-year-old student says, and bursts out laughing.