-
Categories
-
Pharmaceutical Intermediates
-
Active Pharmaceutical Ingredients
-
Food Additives
- Industrial Coatings
- Agrochemicals
- Dyes and Pigments
- Surfactant
- Flavors and Fragrances
- Chemical Reagents
- Catalyst and Auxiliary
- Natural Products
- Inorganic Chemistry
-
Organic Chemistry
-
Biochemical Engineering
- Analytical Chemistry
-
Cosmetic Ingredient
- Water Treatment Chemical
-
Pharmaceutical Intermediates
Promotion
ECHEMI Mall
Wholesale
Weekly Price
Exhibition
News
-
Trade Service
An open-access new paper published October 6 in the journal Ecology of the American Ecological Society presents video footage of predation events taken by two groups of drones, providing new evidence that orcas are capable of chasing and capturing white sharks
.
Orcas have been observed preying on other species of sharks, but direct evidence of orcas preying on white sharks is the first of its kind
.
Alison Towner, senior shark scientist and lead author at the Gansbaai Ocean Power Institute in South Africa, said: "This behavior has never been observed in detail before, and certainly never from the air
.
"
Orcinus orcas (killer whales) and great white sharks (Carcharodon carcharias) are ocean-top predators that shape prey behavior and even entire ecosystems
through direct predation and indirect fear effects 。 Orcas occasionally prey on great white sharks, and only three previous studies have formally described this behavior and associated flight responses of great white sharks, and there has been a lack of direct observational evidence of predatory behavior, which has led to speculation about the hunting strategies of orcas to catch and kill white sharks, and the impact of subsequent behaviors on the surviving white sharks in the area where predation occurred, including clues and timing
of sharks' reactions to these events.
At 14:36 on May 16, 2022, the author of the article used a drone (DJI Mavic Air2S, with a 1-inch CMOS sensor and a 20 millimeter pixel camera) at Hartenbos Beach in Mossel Bay, South Africa, to photograph how five orcas chased and killed a great white shark
.
Although a video taken by the drone aired in June, it was only part
of the entire hour-long manhunt for multiple sharks.
The new paper provides a more complete video as well as data analysis from a comprehensive set of data showing that great white sharks are fleeing South Africa's Mossel Bay area for weeks
.
Two video sequences at 14 hours 07 minutes and 14 hours and 27 minutes show two different orcas followed by a great white shark
whose length is less than the length of the orca's body.
In both clips, the sharks exhibit evasive behavior, tightly circling back, with the whales following, but they both move very slowly — the study also provides new insights into
sharks trying to escape orca capture.
On two occasions, the orca approached the shark slowly at close range, and instead of running away, the shark approached the orca closely, leaving it in sight — a common tactic
used by seals and turtles to avoid sharks.
However, orcas are social and hunt in groups, and the researchers believe these behaviors may disable the white shark's surround strategy
.
The article confirms that a notorious killer whale, known locally as the "Starboard," ate a large piece of suspected shark liver
on the surface of the ocean.
The new video also reveals how another killer whale bit into a great white shark
.
The new study also analyzes survey data
from drones and cage dive vessels before and after these predation events.
Great white sharks can be seen every day in the weeks leading up to the predation incident, and multiple sharks
can be seen on the day of the predation incident.
However, only one great white shark was seen in the 45 days after the predation, which confirmed the shark's escape response
.
Orcas are highly intelligent social animals
.
Their herd hunting style makes them incredibly effective predators," said marine mammal expert and study co-author Dr.
Simon Elwen, a research assistant
at Stellenbosch University.
"I first met Starboard in 2015, when it and its partner 'Port' were suspected of killing 7 gill sharks
.
In 2019, we saw them kill a copper shark, but this new discovery is really another matter," said
David Hurwitz, a resident whale watching worker at the local boat company.
"In 2015 and 2017, we first observed the escape response of seven gill sharks and great white sharks to the appearance of orcas
.
Sharks eventually abandon their former primary habitat, which has had a significant knock-on effect on both ecosystems and shark-related tourism," said Dr Alison Kock, shark expert and marine biologist in South Africa's
national parks.
Previous studies have documented how new behaviors in orca populations
are transmitted through "population culture transmission.
" The authors argue that if more orcas adopt the practice of killing white sharks, the behavior will have a broader impact on
shark populations.
Watch the video https://doi.
org/10.
6084/m9.
figshare.
20625222.
v1
Journal Reference:
Alison V.
Towner, Alison A.
Kock, Christiaan Stopforth, David Hurwitz, Simon H.
Elwen.
Direct observation of killer whales predating on white sharks and evidence of a flight response.
Ecology, 2022; DOI: 10.
1002/ecy.
3875