ba-dum ba-dum

Why the image of a shark's fin above water is an outdated stereotype

The image is "probably not a very accurate picture."

The scariest imaginable moment at the beach — a shark attack — is stereotypically preceded by a fin-above-water sighting. Because of Jaws when we think of this fin above-water scenario, our imaginations typically leap to great white sharks. Bruce, after all, was a supposedly mutated one.

But while that shoreline situation is ready-made for a summery ocean horror movie, new research on the feeding habits of great white sharks suggests that scene it's actually quite unlikely to unfold IRL.

Great whites mostly feed in the middle and bottom of the ocean, finds a recent analysis of the contents of the sharks' stomachs. Researchers from Australia studied 40 juvenile white sharks, Carcharodon carcharia, to better understand the animals' feeding and migration habits.

In recognition of the 45th anniversary of the release of Jaws, Inverse is sharing weird-but-true stories about sharks.

With serrated, six-inch teeth and a forceful bite, great white sharks are formidable ocean predators. Given the feeding habits of the ocean's scariest fish, however, salmon have a lot more to be afraid of than humans.

Great white shark teeth — like these, in a shark near Queensland, Australia — are not here to play. Andrew Holt

The study, published June 7 in the journal Frontiers in Marine Science, breaks down the findings by type of fish chomped on and where they're found in the ocean:

  • 32.3 percent: Mid-water swimming fish (salmon)
  • 17.4 percent: Ocean bottom fish (sole, flathead fish)
  • 14.9 percent: Ocean bottom batoid fish (stingrays)
  • 5 percent: Reef fish (eastern blue groper)

The data runs counter to the old trope of a shoreline shark, terrorizing beachgoers, the researchers say.

“The stereotype of a shark’s dorsal fin above the surface as it hunts is probably not a very accurate picture,” lead author Richard Grainger, a Ph.D. candidate at the University of Sydney, said.

Grainger said the findings line up with past studies involving tagging sharks, which have shown that the predators spend a good chunk of down deep below the ocean's surface.

Since the observed sharks were on the younger side, they weren't hunting the bigger prey some sharks are known for — like cephalopods, dolphins, and other sharks. The sharks aren't up to nabbing that kind of prey until they're more than 7 feet long, Grainger said.

Great white shark, Neptune Island, Australia.Image Source

Testing the waters — Based on proximity alone, humans have probably over-hyped how realistic it is to be concerned about a shark attack at the beach.

That's not to say that sharks don't attack humans — sometimes, they do. In 2019 there were 64 unprovoked shark attacks on humans and 41 confirmed provoked attacks, according to the International Shark Attack File.

Why attacks happen may have more to do with sharks' natural curiosity than a desire to eat humans as a treat.

"If a shark sees a human splashing in the water, it may try to investigate, leading to an accidental attack," reports the National Oceanic and Atmospheric Administration.

There are more than 500 shark species on Earth, but only about a dozen of them have even been involved in attacks on humans.

In fact, sharks should probably be the ones panicking when they see a human. People hunt the large fish for meat and organs and use them in foods like shark fin soup and products like lubricants and leather.

The new great white feeding study may help protect sharks by providing data on where they live and how they migrate — while also debunking the notion that we should be on the lookout for shark fins off the shore.

Abstract: Establishing diets and dietary generalism in marine top predators is critical for understanding their ecological roles and responses to environmental fluctuations. Nutrition plays a key mediatory role in species-environment interactions, yet descriptions of marine predators’ diets are usually limited to the combinations of prey species consumed. Here we combined stomach contents analysis (n = 40), literature prey nutritional data and a multidimensional nutritional niche framework to establish the diet and niche breadths of white sharks (Carcharodon carcharias; mean ± SD precaudal length = 187.9 ± 46.4 cm, range = 123.8–369.0 cm) caught incidentally off New South Wales (NSW), Australia. Our nutritional framework also facilitated the incorporation of existing literature diet information for South African white sharks to further evaluate nutritional niches across populations and sizes. Although teleosts including pelagic eastern Australian salmon (Arripis trutta) were the predominant prey for juvenile white sharks in NSW, the diversity of benthic and reef-associated species and batoids suggests regular benthic foraging. Despite a small sample size (n = 18 and 19 males and females, respectively), there was evidence of increased batoid consumption by males relative to females, and a potential size-based increase in shark and mammal prey consumption, corroborating established ontogenetic increases in trophic level documented elsewhere for white sharks. Estimated nutritional intakes and niche breadths did not differ among sexes. Niche breadths were also similar between juvenile white sharks from Australia and South Africa. An increase in nutritional niche breadth with shark size was detected, associated with lipid consumption, which we suggest may relate to shifting nutritional goals linked with expanding migratory ranges.
Related Tags
Share: