Fear of sharks isn’t just an emotional reaction to exploit by TV producers like Discovery Channel, the home of Shark Week. It might also be an important factor in keeping the ocean’s ecosystems in balance.
An international team of researchers published their evidence for that claim today in the Journal of Animal Ecology. They’ve also provided a nice video, complete with roaming sharks, so that you can see some of what they’re doing for yourself.
The short version is that the researchers have determined that if prey animals don’t have to be afraid of sharks, they may keep grazing the vegetarian in an area until it’s completely destroyed.
However, when sharks move into an area, herbivores like turtles and sea cows decide to swim off in search of safer pastures. By keeping the herbivores in motion, the sharks may not know it, but they’re providing a valuable service in keeping the seagrasses from becoming overgrazed.
“Predators can have major impacts without having to eat anything, because animals will change their behavior to avoid becoming a meal,” marine scientist Mike Heithaus explained in a Florida International University (FIU) statement. Hey, it sounds pretty reasonable to me.
In addition to three Florida International University researchers, the international team included scientists from the University of Washington in Seattle and Simon Frasier University in Canada. The new fear of sharks study was conducted within the seagrass beds of the intimidatingly named Shark Bay, Australia.
Heithaus also pointed to another study he’d participated in, which said that up to 100 million sharks a year may be caught worldwide — an unsustainable rate that could lead to the extinction of multiple shark species.
Unfortunately, the loss of the sharks won’t stop there, because their disappearance would likely have a cascading effect on the entire ocean ecosystem.
Without sharks, prey animals would likely lose the fear of sharks that stops them from overgrazing.
[shark photo by Andrea Izotti via Shutterstock]