(Press-News.org) Ecosystem disrupted following the disappearance of Great white sharks, new study finds
Known for their powerful ability to launch out of the water in pursuit of prey, the loss of Great white sharks from False Bay in South Africa has scientists and conservationists concerned about the rippling effects on the ecosystem.
Miami, Florida – A new study published in the journal Frontiers in Marine Science, has uncovered evidence of far-reaching ecosystem consequences following the disappearance of Great white sharks (Carcharodon carcharias) from False Bay, South Africa. The research, conducted by scientists at the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science, spans over two decades and documents cascading ecological disruptions, underscoring the crucial role apex predators play in maintaining ocean health.
Key Findings:
Decline of Great white sharks: Historically abundant in False Bay, Great white sharks have experienced a dramatic decline and subsequent disappearance. Potential factors contributing to their loss include decades of unsustainable captures in nets intended to protect bathers and some recent instances of predation by Orcas.
Ecosystem Disruption: The absence of Great White sharks has led to an increase in Cape fur seals (Arctocephalus pusillus) and sevengill sharks (Notorynchus cepedianus) and an associated decline in fish that the seals feed on and smaller shark species that the sevengills prey on, illustrating the ripple effect of losing an ocean top predator.
Empirical Evidence: The study provides real-world evidence of food web cascades driven by the loss of top-down predation pressure from great white sharks, consistent with ecological theory and laboratory experiments.
Using a combination of long-term boat-based surveys of shark sightings, citizen science observations on Cape fur seals, and Baited Remote Underwater Video Surveys (BRUVS) of fishes and small sharks, the study provides evidence that the absence of Great white sharks has triggered significant shifts in the marine food web.
“The loss of this iconic apex predator has led to an increase in sightings of Cape fur seals and sevengill sharks, which in turn has coincided with a decline in the species that they rely on for food,” said Neil Hammerschlag, Ph.D., the study’s lead author. Hammerschlag conducted the research while at the Shark Research and Conservation Program at the University of Miami Rosenstiel School. “These changes align with long established ecological theories that predict the removal of a top predator, leads to cascading effects on the marine food web.”
“The use of underwater video surveys conducted more than a decade apart provided us with a snapshot of the food web both before and after the disappearance of white sharks from False Bay,” said Yakira Herskowitz, a co-author of the study and a Rosenstiel School former graduate student that analyzed underwater video data. “The number of individuals of a given species recorded on the videos not only informs us about their numerical abundance, but also their behavior, as species under increased predation risk often become more elusive and are thus less likely to be detected on our cameras”
The researchers say the study provides empirical evidence that the disappearance of Great white sharks creates profound consequences for marine ecosystems. “Without these apex predators to regulate populations, we are seeing measurable changes that could have long-term effects on ocean health.” Hammerschlag added.
The findings emphasize the importance of global shark conservation efforts, as their loss could have long term consequences on marine ecosystems. Given the global reliance on healthy oceans for food, recreation, and ecosystem services, protecting large sharks is essential to maintaining biodiversity.
Funding for this study was provided by the Isermann Family Foundation and the Shark Research Foundation. The study, titled “Evidence of cascading ecosystem effects following the loss of white sharks from False Bay, South Africa”, was published on March 25, 2025 as an open-access paper in Frontiers in Marine Science. The authors include Neil Hammerschlag and Yakira Herskowitz from the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, Chris Fallows from Apex Shark Expeditions, and Thiago B.A. Couto, from Lancaster Environment Centre, Lancaster University.
About the University of Miami
The University of Miami is a private research university and academic health system with a distinct geographic capacity to connect institutions, individuals, and ideas across the hemisphere and around the world. The University’s vibrant and diverse academic community comprises 12 schools and colleges serving more than 17,000 undergraduate and graduate students in more than 180 majors and programs. Located within one of the most dynamic and multicultural cities in the world, the University is building new bridges across geographic, cultural, and intellectual borders, bringing a passion for scholarly excellence, a spirit of innovation, a respect for including and elevating diverse voices, and a commitment to tackling the challenges facing our world. Founded in the 1940’s, the Rosenstiel School of Marine, Atmospheric, and Earth Science has grown into one of the world’s premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life. www.earth.miami.edu.
END
By using new geometric shapes in the shock-absorbing material, researchers at the Universities of Gothenburg and Isfahan have developed a bicycle helmet that provides better protection against head injuries. The material absorbs shock by contracting bilaterally.
Bicycle helmets are important for protecting cyclists from head injuries, but traditional designs have limitations in terms of impact absorption and fit. Researchers at the University of Gothenburg and the University of Isfahan in Iran designed a bicycle helmet whose shock-absorbing ...
HOUSTON, Texas, USA, 25 March 2025 – Schizophrenia affects millions worldwide, yet its causes remain one of the greatest medical mysteries. In an exclusive Genomic Press Interview, Dr. Consuelo Walss-Bass, a pioneering researcher in psychiatric genetics, shares how both genetic predisposition and environmental factors contribute to severe mental health disorders. As the John S. Dunn Foundation Distinguished Chair in Psychiatry at UTHealth Houston, Dr. Walss-Bass has dedicated her career to understanding these mechanisms, transforming scientific discoveries into real-world applications ...
The Super-Kamiokande and T2K Collaborations present a joint measurement of neutrino oscillation parameters from their atmospheric and beam neutrino data. It uses a common interaction model for events overlapping in neutrino energy and correlated detector systematic uncertainties between the two datasets, which are found to be compatible. Using 3244.4 days of atmospheric data and a beam exposure of 19.7(16.3) x 1020 protons on target in (anti)neutrino mode, the analysis finds a 1.9???? exclusion ...
Crashes on electric scooters are mostly due to the behaviour of the riders, with one-handed steering and riding in a group being some of the largest risk factors. The researchers are also concerned about riders who deliberately crash or cause dangerous situations when riding, a phenomenon that seems to be specific to electric scooters. This is shown by a study from Chalmers University of Technology in Sweden, which for the first time examines the causes behind crashes with electric scooters from naturalistic data within an urban environment.
The arrival of electric scooters in cities has meant an opportunity to quickly and smoothly make shorter trips. But not ...
Abstract
The National Institute of Information and Communications Technology (NICT, President: TOKUDA Hideyuki, Ph.D.) has revealed, through fMRI-based brain activity analysis, that multiple regions in the human cerebral cortex flexibly represent numerical quantity. This finding comes from research by HAYASHI Masamichi (Researcher (Tenure-Track)) at Center for Information and Neural Networks (CiNet), part of NICT’s Advanced ICT Research Institute, in collaboration with the University of Tokyo’s graduate student KIDO Teruaki (NICT ...
Depression is a mental health condition that affects 280 million people worldwide. It is twice as common in women than men and this pattern starts to develop during adolescence. Researchers have studied the biological processes that drive depression in adults and shown a potential role for the kynurenine pathway, but this is the first time it has been investigated in adolescents in relation to biological sex.
The study was published in Biological Psychiatry and funded by MQ Mental Health Research and supported by the National Institute for Health and Care Research (NIHR) Maudsley Biomedical Research Centre (BRC).
The ‘kynurenine ...
Artisanal fishers can be almost as accurate as satellite data when it comes to their awareness of features that can be found in the marine environment, a new study has shown.
Published in the journal Ocean and Coastal Management, the research set out to establish the value of local ecological knowledge (LEK) and its ability to generate high quality habitat maps around five Greek islands in the eastern Aegean Sea.
Ten fishermen, based on their individual experience and knowledge, were asked to pinpoint areas where they believed seagrass beds could be found along the coastlines of their respective islands.
The maps they produced were then compared ...
Pro-environmental behaviour increases among school students who participate in insect-related citizen science projects, according to new research from the University of Adelaide.
Students who participated in citizen science project Insect Investigators, which engages students in the discovery of new insects, not only expressed an intention to change their personal behaviour but also to encourage others to protect nature.
“As a result of their involvement in this program, students expressed intentions to further engage in insect–science–nature activities,” says the University of Adelaide’s Dr Erinn Fagan-Jeffries, who contributed ...
Electrochemical CO2 reduction (ECR) driven by green electricity represents a promising strategy for CO2 mitigation and utilization by producing fuels and chemicals. Tandem strategy based on multifunctional tandem catalysts or cascade reactors enables deep CO2 reduction to high-value multi-carbon products. Nevertheless, it is challenging to precisely regulate the multi-step reaction pathways toward efficient CO2 conversion. A comprehensive understanding of the tandem reaction mechanisms is crucial for guiding the rational design of advanced catalysts and reactor systems to address these challenges.
This review systematically ...
A recent study published in Soil Ecology Letters has elucidated the combined effects of soil amendments and pest attacks on plant-induced defence mechanisms and their impact on the behaviour of biological control agents. The research, conducted by the Spanish National Research Council (CSIC) and Fundación MEDINA, focused on the utilisation of vermicomposted olive mill waste as a soil amendment and its consequence on the tri-trophic interactions between olive trees (Olea europaea), ...
