Research examines tweets during Hurricane María to analyze social media use during disasters

Understanding how social media is used during a disaster can help with disaster preparedness and recovery for future events, says urban and regional planning professor Omar Pérez Figueroa

UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN, NEWS BUREAU

 

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UNDERSTANDING HOW SOCIAL MEDIA IS USED DURING A DISASTER CAN HELP WITH DISASTER PREPAREDNESS AND RECOVERY FOR FUTURE EVENTS, SAYS UNIVERSITY OF ILLINOIS URBANA-CHAMPAIGN URBAN AND REGIONAL PLANNING PROFESSOR OMAR PÉREZ FIGUEROA.

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CREDIT: PHOTO BY FRED ZWICKY

CHAMPAIGN, Ill. — Social media can be a useful tool for communicating during extreme weather events. Omar Pérez Figueroa, an urban and regional planning professor at the University of Illinois Urbana-Champaign, examined how Twitter (now X) was used when Hurricane María hit Puerto Rico in 2017.

His findings are published in the Journal of Environmental Studies and Sciences.

Pérez Figueroa studies how impoverished and marginalized communities address environmental inequalities, water governance and disaster resilience.

For his research on social media and risk communication, he collected data from Twitter before the platform changed its name, so he continued to refer to it as Twitter for his study. He analyzed a sample of more than 2,000 tweets from before Hurricane María made landfall to six months after the storm to determine “what the event tells us about the reactions and behavior of people, and what is useful to understand to be better prepared.”

Pérez Figueroa analyzed the timing of the tweets and their geographic distribution. Most of them were made prior to landfall, with smaller peaks of activity at later times – for example, when the Federal Emergency Management Agency deleted Puerto Rican disaster statistics from its website. In the U.S., those tweeting about the hurricane were highly concentrated in Florida, California, New York and Texas, all areas with large Puerto Rican populations.

The sample included tweets from Puerto Rico, despite the collapse of the island’s power grid. Pérez Figueroa said Twitter doesn’t require a strong signal, making sending messages under disaster conditions more accessible.

He identified three main categories of messages: information about what was happening on the ground in Puerto Rico; understanding the social and political conditions that turned the hurricane into a disaster; and emotional messages seeking help or expressing support. Those in Puerto Rico used social media to inform others about their condition and location, ask for and receive help, and document the disaster.

Pérez Figueroa wrote that many tweets about the sociopolitical causes of the disaster blamed local and federal governments for their slow and inefficient response. He said it underscored the use of social media in solidarity and grassroots recovery efforts; as a tool to pressure for prompt government response and the development of policies that address vulnerabilities; and to communicate needs and raise awareness among people not directly affected by the local event about where to donate.

The tweets included information about the Guajataca Dam failure as it occurred. 

“Being able to access critical data during and after a disaster can provide the difference between life and death, especially for those on the ground. Recognizing the increasing use of social media for disaster response and aid can increase communities’ disaster resilience, especially when the communities hardest hit have limited communication and are remote, like the case of Puerto Rico,” Pérez Figueroa wrote.

In addition to aiding in preparedness and recovery for future disasters, the research served as a case study to test and refine a framework for examining disaster social media communication, Pérez Figueroa said.

“Understanding how individuals use Twitter during disasters and in the immediate aftermath will be important as hurricanes occur more frequently, and as the public continues to turn to social media as a mainstream news source. Public health and disaster response organizations will benefit from a more detailed understanding as to who and how communication on social media can play a role in mitigating the public health burdens that result from disaster events,” he wrote.

Pérez Figueroa said areas for future research include how traditional media can influence discussions on social media, how narratives on the two differ, whether social media influences emergency responders and policymakers to improve disaster response, and how groups from different socioeconomic levels use social media during disasters.

 

 

Editor’s notes: To contact Omar Pérez Figueroa, email operez10@illinois.edu.

The paper “A content analysis of social media discourse during Hurricane María: filling a void when traditional media are silent” is available online.

DOI: https://doi.org/10.1007/s13412-024-00909-1

 

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JOURNAL

Journal of Environmental Studies and Sciences

DOI

10.1007/s13412-024-00909-1 

METHOD OF RESEARCH

Content analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

A content analysis of social media discourse during Hurricane María: filling a void when traditional media are silent

Floridians’ and Texans’ perceptions of hurricane risk

PNAS NEXUS

 

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TROPICAL CYCLONE STORM TRACKS AND FORCE WINDS FOR HURRICANES HARVEY, IRMA, AND MICHAEL. THE SOLID LINES REPRESENT THE STORM TRACKS FOR EACH TROPICAL CYCLONE. STUDY PARTICIPANTS, ESPECIALLY THOSE IN FLORIDA, EXPERIENCED REPEATED EXPOSURE TO MAJOR TROPICAL CYCLONES DURING THE STUDY PERIOD. STUDY PARTICIPANTS SHOWN IN THIS FIGURE ARE THOSE WHO RESPONDED TO WAVE 1. 

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CREDIT: NINA BERLIN RUBIN

Rapid climate change is prompting adaptation to threats such as tropical cyclones, wildfires, and droughts—but relatively trivial adaptation actions may lull people into inaccurate perceptions of their personal risk. Researchers from the University of California, Irvine; Stanford University; and the University of California, Los Angeles surveyed 2,774 Texas and Florida residents about tropical cyclones—also known in North America as hurricanes—five times between 2017 and 2022. The survey window included three major landfalling tropical cyclones: Hurricanes Harvey (2017), Irma (2017), and Michael (2018). Participants were recruited through the probability-based online panel KnowledgePanel and asked about their perceived risk from tropical cyclones, as well as adaptation activities, including assembling an emergency supply kit, installing hurricane shutters, developing and practicing an emergency plan, and purchasing flood insurance. Gabrielle Wong-Parodi and colleagues found that perception of personal risk, including the likelihood of injury and home damage, declined as time passed after hurricanes. On average, personal tropical cyclone risk perceptions were positively associated with adaptation actions. However, adapters also showed declining risk perception over time. Yet, the authors note that climate change is making tropical cyclones more intense over time— and adaptation activities cannot reduce overall risk of event occurrence. According to the authors, these activities may counterintuitively lower personal risk perceptions and subsequent adaptation behaviors, paradoxically leaving people less prepared for future climate threats. The authors contend that policies and programs supporting sustainment of long-term proactive adaptations are warranted, especially among those who may have fewer resources.

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JOURNAL

PNAS Nexus

ARTICLE TITLE

A longitudinal investigation of risk perceptions and adaptation behavior in the US Gulf Coast

ARTICLE PUBLICATION DATE

9-Apr-2024

 

‘Teacher Toads’ can save native animals from toxic cane toads

Large multi-year study shows that juvenile "taster toads" taught goannas to avoid eating poisonous cane toads, preventing population collapse

MACQUARIE UNIVERSITY

 

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CANE RANGERS: DR WARD-FEAR AND INDIGENOUS RANGERS IN THE KIMBERLEY INSPECT ADULT CANE TOADS AT THE RANGER FORUM PUT ON BY THE CANE TOAD COALITION. PHOTO: WWF AUSTRALIA

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CREDIT: WWF AUSTRALIA

A landmark study published in the journal Conservation Letters this month outlines a clever strategy pioneered by Macquarie University researchers to protect vulnerable native species from the devastating impacts of invasive cane toads.

The study, led by wildlife biologist Dr Georgia Ward-Fear, a Postdoctoral Research Fellow at Macquarie University, showed high survival rates in groups of goannas in the remote Kimberley region of Western Australia trained to avoid poisonous cane toads.

“Our work in adaptive management for conservation is based on decades of cane toad research and involves a broad group of people and organisations,” says Dr Ward-Fear.

“Cane toads crossed into Western Australia in 2009 and have made it most of the way across the Kimberley, with disastrous results.

“When apex predators like goannas eat an adult cane toad, they die quickly and painfully – and when they disappear, it affects the whole food web.”

Together with Macquarie University evolutionary biologist Professor Rick Shine, Dr Ward-Fear ran small scale field trials in 2016 showing when lizards are first exposed to younger, smaller cane toads, they get sick from eating them, but don’t die. Most will then avoid eating another cane toad and survive.

“It's a form of ecological immunisation, building resilience in native wildlife against invasive species,” Dr Ward-Fear says.

Teaching Taste Aversion

Using sites at the frontline of the cane toad invasion, the study field-tested this method (called ‘conditioned taste aversion’) on groups of yellow-spotted monitors, a tropical goanna species heavily impacted by cane toad spread.

“Cane toads have so far been unstoppable, so we wanted to scale up our success in small areas, to a landscape approach,” says Dr Ward-Fear.

Initially, the team taste-trained individual goannas in the field, tracking them with radio tags during the arrival of the highly poisonous adult cane toads heading the invasion frontline. The taste-trained goannas had far better survival rates.

As cane toads arrive, we see a very rapid and huge decline in the larger predators which regulate the food web from the top. This imbalance sends ripples through the whole ecosystem.

The ‘taster toad’ method was then trialled at an ecosystem scale.

The results were remarkable, says Dr Ward-Fear. At control sites which did not introduce the small ‘taster toads’ before the larger,  highly poisonous adult cane toads arrived, goanna populations plummeted by up to 94 per cent.

However, at sites where taste aversion was trialled, goanna populations ranged from 35 per cent to 140 per cent of pre-invasion levels by the time the study finished.

Group effort the key to success

Dr Ward-Fear says this study tracks Australia’s largest cane toad mitigation strategy to date, so upscaling the methodology from individual trials to the ecosystem level was an exercise in logistics and collaborative partnerships.

“The strategy involved releasing thousands of eggs, tadpoles and juvenile cane toads into wild waterbodies in the Fitzroy Valley in Western Australia's Kimberley region, immediately ahead of the invasion frontline,” says Dr Ward-Fear.

This ambitious approach depended heavily on collaboration with the Cane Toad Coalition, a group of research, conservation and land management organisations coordinated by Dr Ward-Fear and Professor Shine, and supported by an Australian Research Council grant.

​Working with the Bunuba Rangers and the Western Australian Department of Biodiversity, Conservation and Attractions to raise then release juvenile toads, the team used camera traps and sardine-tin baits to observe goanna populations.

Food web impact

Goannas, crocodiles and other larger predators are the only species directly affected by cane toads, but the knock-on effect in Northern Australia of losing these animals has been profound, Dr Ward-Fear says.

Cane toads were introduced to Australian sugar cane farms in 1935 to control pests and have since spread across the tropics, decimating populations of native Australian predators who eat them.

"As cane toads arrive, we see a very rapid and huge decline in the larger predators which regulate the food web from the top. This imbalance sends ripples through the whole ecosystem,” she says.

Free from large predators, snakes and lizards breed up in huge numbers, exerting strong pressure on their prey species like frogs and small lizards, who then decline. This can see insect species proliferate, annihilating many plant species.

“Goannas are significant cultural totems for Traditional Owners across northern Australia, and an important bush tucker food,” Dr Ward-Fear says.

“In parts of the Kimberley there can be five different language words associated with a goanna burrow, for example – nesting burrows, night-time burrows and so on, so when that species disappears from the landscape, it's more difficult to practice those aspects of your culture.”

Long term effects

Dr Ward-Fear says although their intervention was targeted to relatively small, specific populations in Western Australia, its results will have long-term impacts.

“By managing the initial impact of the invasion, we see ongoing survival of goanna populations because after cane toads invade and begin breeding, plenty of baby toads will "train" the next generation of goannas, without us having to keep adding more toads to the system.”

Dr Ward-Fear says the research shows that behavioural interventions can be a viable alternative to traditional wildlife management approaches that try to wipe out invasive species – a goal that is often impossible to achieve.

“While it’s impossible to deploy ‘teacher toads’ right across the Australian tropics, we can maintain pockets with healthy predator populations, and potentially these can repopulate areas where goannas have become locally extinct,” she says.

“We’re optimistic that even a single deployment can have long-term effects.”

Dr Georgia Ward-Fear is a wildlife biologist in the School of Natural Sciences. She formed the Cane Toad Coalition and worked with a broad group of stakeholders to trial the large-scale cane toad intervention.

Goanna protectors: Dr Ward-Fear with a yellow-spotted monitor in the Kimberley with the Balanggarra Rangers 

CREDIT

Photo: David Pearson

Totem species: The Yellow-spotted monitor is an important cultural species in northern Australia and plays a key role in ecosystemS

CREDIT

Photo: Georgia Ward-Fear

Collaboration: Dr Ward-Fear worked with a broad group of stakeholders after forming the Cane Toad Coalition, to trial this large cane toad intervention

CREDIT

WWF Australia

JOURNAL

Conservation Letters

DOI

10.1111/conl.13012 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Teacher toads: Buffering apex predators from toxic invaders in a remote tropical landscape

ARTICLE PUBLICATION DATE

8-Apr-2024

 

Experimental collaboration between archaeologists and MeatEater highlights the prevalence of equifinality in archaeological interpretation

KENT STATE UNIVERSITY

 

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CLOVIS FLUTED POINTS HAFTED ONTO WOODEN HANDLES BY MICHAEL WILSON. (IMAGES CREDIT: METIN I. EREN)

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CREDIT: METIN I. EREN

Kent State University’s experimental archaeologists, along with those from several other universities, joined forces with the popular hunting, outdoors, and conservation media platform, MeatEater, Inc., for a unique animal processing experiment, shedding new light on ancient stone knives and showcasing the importance of testing and looking for equifinality.  ‘Equifinality’ is when two or more distinct processes can lead to the same outcome or result.

The Kent State archaeologists included Professor Metin I. Eren, Ph.D.; Assistant Professor Michelle Bebber, Ph.D. and Alumni Michael Wilson (Kent State B.A., ‘18; M.A., ‘21) and Lawrence Mukusha (Kent State M.A., ‘23). The primary objective of the experiment was to test the efficiency of Clovis stone tools in processing a bison, offering insights into early human technologies. ‘Clovis’ refers to 13,000-year-old archaeological culture that represents some of the earliest hunting and gathering peoples in North America.

The experiment was meticulously documented and detailed in a recently published open-access article in the Journal of Archaeological Science: Reports.

While the researchers learned much about Clovis knife efficiency and other aspects of stone tool animal processing, one outcome that the researchers did not anticipate was that several of the replica knives broke during animal processing very similarly to breaks some assume would result from shooting the Clovis points.

“Even though one can use Clovis stone points for both hunting and processing, the breakage resulting from these distinct activities can be similar,” Eren said. “If an archaeological site is found that is comprised of a large animal and broken Clovis points, some archaeologists might assume that's because the points were used to hunt the animal. What our experiment suggests is another interpretation: the animal was already dead and people scavenged it and processed it with knives.”

The researchers also documented several other instances of equifinality, involving bone cut marks, tool functional morphology, and resharpening.  

“I used to think that the power of experimental archaeology was that it allowed us to help reverse engineer past technologies. And it can,” Eren said. “But, I think a more valuable aspect of experimental archaeology that's becoming more and more consequential is that it documents equifinality, providing a vital check on archaeologists’ interpretations.”

Partnering with MeatEater, Inc.
Inspiration for the experiment stemmed from previous conversations that David J. Meltzer, Ph.D. (Southern Methodist University) and Eren had during their guest appearances on The MeatEater Podcast, where discussions about mammoth hunting led to the idea of a collaborative butchery experiment. Meltzer was a co-author on the study.

“The unique skills of the MeatEater crew in animal processing and media documentaries, combined with our expertise in archaeology and artifact recreation, sparked the idea of testing Clovis stone tools’ efficiency,” Eren said.

The entire experiment was recorded by a MeatEater film crew, and an edited version of the video was posted on YouTube as a documentary entitled Butchering a Bison with Clovis Points and Tools (https://www.youtube.com/watch?v=XmsrkFjPiKM).

“It was a career highlight for us to work with all the folks at MeatEater who have amazing experience and skills; we learned so much from them,” Eren said. “And they’re so curious – they’re natural scientists.”

Metin I. Eren resharpening the stone tools with pressure flaking at the site in Montana (left). He also produced an expedient axe with soft hammer percussion (right). (Images credit: Seth Morris).

CREDIT

Seth Morris

 

The large handheld flakes knapped by Metin Eren. (Images credit: Metin I Eren).

CREDIT

Metin I. Eren

LINK TO STUDY: https://doi.org/10.1016/j.jasrep.2024.104480

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JOURNAL

Journal of Archaeological Science

DOI

10.1016/j.jasrep.2024.104480 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Experimental bison butchery using replica hafted Clovis fluted points and large handheld flakes

ARTICLE PUBLICATION DATE

8-Apr-2024

 

Virtue in Japan: perception differences among educational specialists and general public

Researchers explore the notion of virtue in Japan, with potential implications for both academic integrity and educational policy

CHIBA UNIVERSITY

 

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ESS AND THE GP IN JAPAN ASSOCIATE DIFFERENT WORDS WITH VIRTUE. THE FONT SIZE OF EACH WORD OR SET OF WORDS IS PROPORTIONAL TO THE RELATIVE FREQUENCY OF OCCURRENCE.

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CREDIT: KOJI TACHIBANA FROM CHIBA UNIVERSITY IMAGE SOURCE LINK: HTTPS://WWW.FRONTIERSIN.ORG/FILES/ARTICLES/1171247/FPSYG-14-1171247

Virtue is a normative concept comprising a set of moral and social codes acceptable to society. Historically, in the West, especially in ancient Greek and Christian belief systems, virtue was viewed as "excellence" aspirational to all human beings. In contrast, the East, especially in a Confucian belief system, viewed it similarly but being aspirational to only select individuals, such as rulers. However, the rise of modern values and sociopolitical overhauls almost pushed the concept of virtue into oblivion. 

In the 20th century, however, virtue was resurged in academic fields, yet it remained relatively dormant in the public consciousness. Virtue impacts society in multiple ways—it is a concept commonly found in many cultures, associated with psychological and sociological studies, and reflected in the educational curricula of a country. Given that the notion of virtue has a multitiered impact on society, exploring potential perception differences between educational specialists (ESs) and the general public (GP) is the need of the hour. 

A recent study published in Frontiers in Psychology on 15 February 2024 explored these gaps in multicultural Japanese society. The study, conducted by Dr. Koji Tachibana and Dr. Eisuke Nakazawa, revealed that the concept of virtue was relatively unknown to the GP compared to ESs. The results also showed significant differences in how the GP and ESs perceive virtue. The GP identified with passive, emotional virtues, whereas the ESs identified with active, intellectual virtues. Notably, both groups thought positively of virtue but poorly understood the Confucian concept of virtue. 

Dr. Tachibana underscores the significance of the research, stating, "If there is a gap between the GP and ESs on the subject of virtue, where ESs frame discussions or publish textbooks neglecting this gap, they could contain errors in theoretical and empirical research on the concept of virtues and deter the actual design of an education system. Thus, we sought to endeavor on theoretical and practical perspectives to address the gaps between the GP and ESs groups in understanding virtue." 
 
Accordingly, the team conducted an online survey in Japan targeting both groups. They recruited individuals of various ages and genders for the GP group and individuals from academic societies related to philosophy and education for the ES group. Subsequently, they evaluated the responses for the frequency of encountering the term "virtue" in daily life, the impressions associated with virtue, words associated with virtue, virtues that are difficult to understand, and virtues deemed important to either group.

Notably, the researchers arrived at five main conclusions: Firstly, the ES group was more familiar with the term "virtue" when compared to the GP group. Secondly, both groups held positive impressions of virtue. Thirdly, ESs tend to associate more with ancient Greek virtues, although both groups acknowledged Buddhist elements. Fourthly, there existed a mutual lack of understanding of Confucian virtues. Lastly, differences existed in the emphasis on virtues—the GP leans towards Eastern values while ESs toward Western ones.

These findings reveal that the notion of virtue was being perceived differently by different members of society. Practically, this points to the possibility of a gap in the understanding of the notion of virtue among ESs, which, if neglected, can have negative practical implications. The authors believe that since the ESs hold the power to influence the national curriculum, formulate educational policies, and authorize textbooks in the educational system, they must exercise caution in using the notion of virtue. On the contrary, not exercising caution in doing so could have a detrimental impact on the education system.    

Sharing his closing thoughts on the study, Dr. Tachibana says, "Our study showed that ESs and the GP understood virtue differently in Japan. This finding has several social implications in areas such as academic integrity and educational policy." Indeed, the findings of this study could serve as a trailblazer for future studies about the concept of virtue in society. 

About Associate Professor Koji Tachibana
Associate Professor Koji Tachibana specializes in philosophy at the Faculty of Humanities, Chiba University, Japan. He is also an international associate scholar at Georgetown University Medical Center since 2015. Dr. Tachibana investigates the notion of virtue from four perspectives: ancient Greek philosophy, contemporary virtue ethics, Japanese philosophy, and philosophy of science. 
 

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JOURNAL

Frontiers in Psychology

DOI

10.3389/fpsyg.2023.1171247 

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The consciousness of virtue: uncovering the gaps between educational specialists and the general public in their understanding of virtue in Japan

 

Birdfeeders are designed to keep unwanted guests away

UNIVERSITY OF HELSINKI

 

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THE FIRST BIRDFEEDERS WERE MADE IN THE 19TH CENTURY, AND THEIR DESIGN RAPIDLY EVOLVED DURING THE 20TH CENTURY.

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CREDIT: HETA LÄHDESMÄKI

The first birdfeeders were made in the 19th century, and their design rapidly evolved during the 20th century. Researchers at the University of Helsinki and Aalto University consider the evolution of the birdfeeder to be an example of multispecies design, where unwanted guests have shaped the human-made artefact.

Bird feeding is a common hobby in many Western countries and has been studied extensively. Nevertheless, birdfeeders have been studied less, despite being a crucial material part of bird feeding practices.

The researchers noted four major changes in birdfeeder design: first, a roof was placed on top of the feeding board, secondly, the birdfeeder was placed on top of a high stick or was hung from a high place, thirdly, the slit where food was available was reduced in size, and fourthly, automated feeders became much more common. The research conducted at the University of Helsinki and Aalto University suggests that the reason for these design choices was more concerned with excluding species from the feeder rather than feeding birds.

- We argue that a birdfeeder is not essential for feeding birds, as food can simply be thrown on the ground. Birdfeeders were designed to keep unwanted guests, such as rats, corvids, or salmonella, away, so that small-sized birds can obtain more food and are kept safe, says the first author of the paper, postdoctoral researcher in cultural history, Heta Lähdesmäki from the University of Helsinki.

Earlier research has shown that the users of artefacts and technology shape the design of the artefacts. This research used descriptions of birdfeeders and guidelines for bird feeding and birdfeeder structures issued in Finnish newspapers and magazines from the end of the 19th century until the end of the 20th century. The transdisciplinary research combined approaches from environmental history, environmental humanities, design studies, and studies of technology and science to uncover the role of other species than humans in the evolution of technological artefacts.

The phases in the evolution of birdfeeder design were clear and discreet

In the first stage, at the turn of the 20th century, a roof was added to the designs, to keep snow and rainwater away from the food. From the 1910s onward, the birdfeeder was suggested to be placed either hanging or on top of a long stick, to prevent cats that were hunting birds or rats that were after the birdfeed from reaching the birdfeeder. In the 1930s, birdfeeder slits for seeds were recommended to be kept small enough to prevent larger-sized birds from accessing the feed. During the final phase, from the 1970s onwards, Salmonella and other pathogens began worrying people and birdfeeder design began prioritizing easy cleaning and keeping bird faeces away from the feeder.

- The evolution in birdfeeder design is a story of reciprocal actions, where humans want to prevent some species, such as the rat, from accessing birdfeeders by modifying the structure, after which the rats test whether the modification was efficient. The bird table design concurrently tells us a great deal about the changing attitudes towards species in our own backyards, when additional species are perceived to be problematic, says senior author, Academy Research Fellow, ecologist Tuomas Aivelo, University of Helsinki.

- Many articles concerning birdfeeders and bird feeding have been published in Finnish newspapers and magazines, and bird feeding is clearly a dear hobby for many people. While a great deal has been written about welcome guests, such as various endangered species, unwanted guests also elicit an equally passionate discourse. Especially Salmonella has led people who use the “wrong” type of old-fashioned birdfeeders to be branded as the worst threat to small-sized birds, Lähdesmäki says.

 

The bird feeding research will continue by analysing the photos and stories regarding birdfeeders that were obtained from Finnish birdfeeding enthusiasts during winter 2022–23. This research is part of the interdisciplinary Helsinki Urban Rat Project led by Tuomas Aivelo, and it was funded by the Helsinki Institute of Sustainability Science.  

 

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JOURNAL

Environment and Planning E Nature and Space

DOI

10.1177/25148486241242680 

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Bird feeding devices exclude unwelcome visitors. More-than-humans shaping the architecture and technology of birdfeeders in twentieth-century Finland

ARTICLE PUBLICATION DATE

9-Apr-2024

 

What’s quieter than a fish? A school of them

Surprising study finds schools of fish can make less noise than a solitary swimmer

JOHNS HOPKINS UNIVERSITY

 

VIDEO: 

THE TEAM FOUND THAT A SCHOOL OF FISH MOVING TOGETHER IN JUST THE RIGHT WAY WAS STUNNINGLY EFFECTIVE AT NOISE REDUCTION: A SCHOOL OF SEVEN FISH SOUNDED LIKE A SINGLE FISH.

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CREDIT: JOHNS HOPKINS UNIVERSITY

Swimming in schools makes fish surprisingly stealthy underwater, with a group able to sound like a single fish.

The new findings by Johns Hopkins University engineers working with a high-tech simulation of schooling mackerel, offers new insight into why fish swim in schools and promise for the design and operation of much quieter submarines and autonomous undersea vehicles.

“It’s widely known that swimming in groups provides fish with added protection from predators, but we questioned whether it also contributes to reducing their noise,” said senior author Rajat Mittal. “Our results suggest that the substantial decrease in their acoustic signature when swimming in groups, compared to solo swimming, may indeed be another factor driving the formation of fish schools.”

The work is newly published in Bioinspiration & Biomimetics.

The team created a 3D model based on the common mackerel to simulate different numbers of fish swimming, changing up their formations, how close they swam to one another, and the degrees to which their movements synched. The model, which applies to many fish species, simulates one to nine mackerel being propelled forward by their tail fins.

The team found that a school of fish moving together in just the right way was stunningly effective at noise reduction: A school of seven fish sounded like a single fish.

“A predator, such as a shark, may perceive it as hearing a lone fish instead of a group,” Mittal said. “This could have significant implications for prey fish.”

The single biggest key to sound reduction, the team found, was the synchronization of the school’s tail flapping—or actually the lack thereof.

If fish moved in unison, flapping their tail fins at the same time, the sound added up and there was no reduction in total sound. But if they alternated tail flaps, the fish canceled out each other’s sound, the researchers found.

“Sound is a wave,” Mittal said. “Two waves can either add up if they are exactly in phase or they can cancel each other if they are exactly out of phase. That’s kind of what’s happening here though we’re talking about faint sounds that would barely be audible to a human.”

The tail fin movements that reduce sound also generate flow interaction between the fish that allow the fish to swim faster while using less energy, said lead author Ji Zhou, a Johns Hopkins graduate student studying mechanical engineering.

“We find that reduction in flow-generated noise does not have to come at the expense of performance,” Zhou said. “We found cases where significant reductions in noise are accompanied by noticeable increases in per capita thrust, due to the hydrodynamic interactions between the swimmers.”

The team was surprised to find that the sound reduction benefits kick in as soon as one swimming fish joins another. Noise reduction grows as more fish join a school, but the team expects the benefits to cap off at some point.

“Simply being together and swimming in any manner contributes to reducing the sound signature,” Mittal said. “No coordination between the fish is required.”

Next the team plans to add ocean turbulence into the models and create simulations that allow the fish to swim more “freely.”

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Fish swimming in the noisiest [VIDEO] 

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Image of fish swimming in quie [IMAGE] 

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Image of fish in the noisiest [IMAGE]

JOURNAL

Bioinspiration & Biomimetics