Are humans to blame for shark attacks?

August 18, 2011 by Richard Ingham
An apparent increase in shark attacks may well have a human cause, with low-cost air travel but also over-fishing and possibly global warming among the hidden suspects, say experts.

An apparent increase in shark attacks may well have a human cause, with low-cost air travel but also over-fishing and possibly global warming among the hidden suspects, say experts.

Headlines this week were grabbed by a decision to close beaches in the Seychelles after a shark savaged a British honeymooner before the horrified gaze of his spouse, in the second fatal attack there in 15 days.

In Russia's Pacific of Primorye, a shark mauled a 16-year-old boy a day after a man lost his forearms defending his wife. In the Caribbean, a woman vacationing in Puerto Rico received a 30-centimetre (foot-long) shark bite as she swam in a tourist haunt, the bioluminescent bay of Vieques.

According to the International Shark Attack File (ISAF), compiled at the University of Florida, 79 unprovoked shark assaults occurred around the world in 2010, six of which were fatal.

This was the highest number in a decade, amounting to an increase of 25 percent on 2009, when there were 63 attacks with six fatalities, and 49 percent over 2008, which had 53 recorded attacks, four of them mortal.

So far this year, there have been six deaths and seven cases of injuries, according to an unofficial toll compiled by AFP from news reports.

Compared to deaths from smoking, , or even from other animals, the risk is minute, say experts.

"The attention from shark attacks is completely overblown," said Agathe Lefranc, a scientist with a French group, the Association for the Study and Conservation of Salachians (APECS), a category that includes sharks and rays.

say there is little research into the causes of shark attacks but point to several possibilities, all linked to humans themselves.

No. 1 is quite simply the growth in mobility, with cheap air travel and package vacations enabling people to swim, snorkel, surf or dive in places that previously had no human presence.

"The growth in shark attack numbers does not necessarily mean that there is an increase in the rate of shark attacks," says ISAF.

"Rather it most likely is reflective of the ever-increasing amount of time spent in the sea by humans, which increases the odds of interaction between the two affected parties."

David Jacoby, a specialist at the Marine Biological Association (MBA) in Plymouth, southwestern England, said were events that had local causes and often were poorly investigated, if at all.

One case that stands out occurred in the Egyptian resort of Sharm el-Sheikh, where sharks made five attacks in a week in November-December last year, one of which was fatal.

The finger of blame was pointed at a passing livestock transport ship that had dumped sheep carcasesses overboard and at operators who illegally fed sharks to thrill the tourists.

Another question -- but again, lacking sufficient data to answer it -- is the impact on shark behaviour from overfishing and from global warming, which affects ocean temperatures and currents.

"We know that these animals are opportunistic and they go to where food sources are available, and those resources do move, and they are dependent on currents, nutrient-rich patches," said Jacoby.

"It's not just sharks that do this, but all large pelagic predators are drawn to areas where there is high food availability. But whether this is a case of increased human activity is unclear."

A hugely successful fish in evolutionary terms, with a lineage dating back more than 400 million years, the shark is under relentless attack from humans themselves.

A third of open-water shark species, including the great white and the hammerhead, are facing extinction, driven in part by demand in Asia for shark-fin soup, according to the International Union for the Conservation of Nature (IUCN).

Explore further: As sharks dwindle, new laws enacted

Related Stories

As sharks dwindle, new laws enacted

May 28, 2007

Shark fisheries in Mexico and throughout the world are dealing with proposed rules to curb shark hunting in the interest of preserving these predators.

Study: Shark attacks declining

February 13, 2006

University of Florida scientists say shark attacks worldwide were lower in number last year, continuing a five-year downturn.

Shark attack worries? Driving to the beach is more deadly

June 29, 2005

Which is more likely to happen - you being in a car wreck or being bitten by a shark? Those who answered that cars are greater killers win a free trip to the beach. It's really no contest, says a Texas A&M University professor. ...

Ocean's fiercest predators now vulnerable to extinction

February 17, 2008

The numbers of many large shark species have declined by more than half due to increased demand for shark fins and meat, recreational shark fisheries, as well as tuna and swordfish fisheries, where millions of sharks are ...

Recommended for you

Even wild mammals have regional dialects

December 13, 2017

Researchers from Cardiff University's Otter Project have discovered that genetically distinct populations of wild otters from across the UK have their own regional odours for communicating vital information to each other. ...


Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (1) Aug 18, 2011
Let's take any apex predator and put any prey, not just it's natural prey, into a confined habitat with it and see what happens.

I highly doubt it would be much different than shark attack scenarios. The predator will have an easy lunch.

You wouldn't go jump in a swamp full of alligators and go dance and swim and kick around in it, so then why exect any different in the ocean with sharks? In most cases, YOU are an easier target than their natural prey, AND you are a bigger, one-stop feast than most of their natural prey. In many cases, it makes perfect sense for a shark to attack you and get a big, free meal, than to chase a much faster bait fish.

Even if he only gets away with an arm or a leg, that probably cost him less energy and more reward than a bait fish or sea bird.
1 / 5 (1) Aug 21, 2011
The article is pure speculation. Great whites were tagged off California and were found to pass a very popular and populated beach hundreds of times in the course of a few months even going so far as to swim under the pier without one single shark attack in that area.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.