Sharks behaving dangerously and unpredictably? Overfishing and waste-disposal is only part of the explanation, says underwater photographer and shark conservationist EKREM PARMAKSIZ – he believes there are two more basic, and concerning, explanations
After the recent shark attack that killed young Russian swimmer Vladimir Popov in the Egyptian resort of Hurghada, the question was squarely back on the table – what is going on in the Red Sea?
Two of the five shark fatalities recorded worldwide in 2022 also occurred in these waters – both of them in Hurghada, unprovoked and close together in time. And now here we are with another unprovoked killing.
As divers are well aware, shark “attacks” anywhere in the world are rare. According to the International Shark Attack File, there were 57 cases last year, the vast majority non-fatal. We usually hesitate to call them attacks at all, preferring to think of them as cases of mistaken identity or investigative bites.
But these deadly occurrences in the Red Sea in the past 12 months were unsettling and, widening it out, there have been nine fatalities there in the past 10 years. Are the blue waters of the Red Sea turning red for any particular reason?
According to local environmental body HEPCA, the conditions that give rise to sharks biting humans are caused by human activities such as overfishing, errant waste-disposal and dumping of animal carcasses, as reported on Divernet after the incident.
Certainly such maritime abuses are taking their toll on the sea, but far from being a new phenomenon they have all been occurring for decades. Can all responsibility be laid at their door?
Perhaps it could be argued that these abuses have simply been laying the foundations for what is happening now. Experts will insist, for example, that animal carcasses and other food waste dumped by vessels disrupt sharks’ natural feeding patterns and cause significant behavioural changes.
Yet research carried out in the Bahamas found no increase in unprovoked shark attacks, despite an increasing number of baited dives there at the time. I respect HEPCA's statements and the views of other experts but I believe there are another two other important and connected factors to consider.
The first one is the “behavioural thermo-regulation” hypothesis. In an article in Diver magazine in 2019 I suggested that increases in Red Sea water temperatures over the past 20 years were causing behavioural changes in sharks that were finding it difficult to adapt.
Pelagic ectotherms such as sharks need to maintain internal temperatures within a favourable range to maximise their performance. Studies have shown temperature to be an important driver of movement and space use for some shark species. It affects physiological and biological processes such as growth rate, migration, feeding, metabolism, embryonic development and digestion.
Water temperature is arguably the most influential physical driver governing sharks’ movements. If these animals are unable to control the situation for extended periods, this must be having an impact on them. It could make their behaviour less predictable, more violently explosive and erratic.
Shark numbers rising
The second factor is that, while the global population of sharks has crashed by more than 70% in the past 50 years, the numbers occupying the Red Sea are, surprisingly, rising. Sharks are migrating from the Indian Ocean, driven by climate change and also by human activities.
Climate change means rising water temperatures. As seas become more temperate and more tropical, creatures such as sharks prefer to stay longer in these waters – but become more aggressive if and when they fail to find their usual food.
I have been diving, observing and researching sharks in the Red Sea extensively over the past 14 years, and feel it’s important to add these factors to HEPCA’s list and accord them due weight.
There is no doubt that more scientific data is necessary if we are to be able to predict how sharks might be increasingly affected by climate change and other human modifications to water-temperature patterns.
The tiger shark that killed Popov was a large adult tiger shark that had likely migrated from the Indian Ocean. More than ever, various species of sharks are migrating from there, and increasingly the movement is shifting from normal seasonal migration to more permanent transfers.
When I had an impressive encounter with a bull shark at Daedalus Reef six months ago, I was already wondering whether or not the Red Sea would soon provide such sharks’ new permanent habitat. Is it any wonder that contact with humans will be ever more likely – and that there might be times when that contact turns ugly?
HEPCA was approached for comment.