Study finds fish rubbing up against their predators -- sharks
Researchers suggest this behavior plays a greater ecological role than previously known

Date:
November 4, 2021
Source:
University of Miami Rosenstiel School of Marine & Atmospheric
Science
Summary:
While rubbing up against a shark sounds like a risky move if you're
a fish, a collaborative research team found that this behavior is
frequent, widespread, and could play a previously unappreciated
important ecological role for aquatic animals.



FULL STORY ========================================================================== While rubbing up against a shark sounds like a risky move if you're a
fish, a collaborative research team led by the University of Miami (UM)
Shark Research and Conservation Program at the Rosenstiel School of Marine
and Atmospheric Science found that this behavior is frequent, widespread,
and could play a previously unappreciated important ecological role for
aquatic animals.


========================================================================== Although instances of fish chaffing against sharks has previously
been observed, this study finds this cross-species behavior to be
more pervasive than previously understood. The research team examined underwater photos, video, drone footage, and witness reports to find 47 instances of fish rubbing themselves against a shark's skin. The chafing events, which were documented in 13 locations around the world, varied
in duration from eight seconds to over five minutes. They recorded 12
fin fish chafing against eight different species of shark, including
great whites. The team even documented silky sharks chafing on the head
of a whale shark. The number of fish chafing against sharks ranged from
one to over 100 individuals at a time.

"While chafing has been well documented between fish and inanimate
objects, such as sand or rocky substrate, this shark-chaffing phenomenon appears to be the only scenario in nature where prey actively seek out
and rubs up against a predator," said UM Rosenstiel School graduate
student Lacey Williams, who co- led the study with fellow graduate
student Alexandra Anstett.

Using aerial drone surveys in Plettenberg Bay, South Africa, Williams
and Anstett documented 25 occurrences of a leervis fish turning to chafe against a passing great white shark.

"While we don't exactly know why it's happening, we have a few
theories. Shark skin is covered in small tooth-like scales called dermal denticles, which provide a rough sandpaper surface for the chafing
fish," said UM Rosenstiel School research associate professor and
study co-author Neil Hammerschlag. "We suspect that chafing against
shark skin might play a vital role in the removal of parasites
or other skin irritants, thus improving fish health and fitness." ========================================================================== Story Source: Materials provided by University_of_Miami_Rosenstiel_School_of_Marine_&
Atmospheric_Science. Original written by Diana Udel. Note: Content may
be edited for style and length.


========================================================================== Journal Reference:
1. Lacey H. Williams, Alexandra Anstett, Victor Bach Mun~oz, John
Chisholm,
Chris Fallows, Jonathan R. Green, Jesu's Erick Higuera Rivas,
Gregory Skomal, Megan Winton, Neil Hammerschlag. Sharks as
exfoliators: widespread chafing between marine organisms suggests
an unexplored ecological role. Ecology, 2021; DOI: 10.1002/ecy.3570 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211104162628.htm

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