It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Friday, August 20, 2021
4D back-projection method reveals seismicity that initiated in the lower mantle in 2015
By using a 4D back-projection method, researchers traced the behavior of a 2015 earthquake beneath Japan’s Ogasawara (Bonin) Islands, pictured here. Credit: Anagounagi, CC BY-SA 4.0
On 30 May 2015, a magnitude 7.9 earthquake took place beneath Japan's remote Ogasawara (Bonin) Islands, located about 1,000 kilometers south of Tokyo. The seismic activity occurred over 660 kilometers below Earth's surface, near the transition between the upper and lower mantle. The mechanism of deep-focus earthquakes, like the 2015 quake, has long been mysterious—the extremely high pressure and temperature at these depths should result in rocks deforming, rather than fracturing as in shallower earthquakes.
By using a 4D back-projection method, Kiser et al. traced the path of the 2015 earthquake and identified, for the first time,seismic activitythat initiated in the lower mantle. They relied on measurements by the High Sensitivity Seismograph Network, or Hi-net, a network of seismic stations distributed across Japan. Thedatacaptured by these instruments are analogous to ripples in a pond produced by a dropped pebble: By calculating how seismic waves spread, the researchers were able to pinpoint the path of the deep-focus quake.
The team found that the main shock initiated at a depth of 660 kilometers, then propagated to the west-northwest for at least eight seconds while decreasing in depth. Analyses of the two hours following the main shock identified aftershocks between depths of 624 and 751 kilometers. A common model for deep-focus earthquakes is transformational faulting; in other words, instability causes the transition of olivine in a subducting slab into a denser form, spinel. The aftershocks below 700 kilometers, however, occurred outside the zone where this transition occurs. The authors propose that the deep seismicity may have resulted from stress changes caused by settling of a segment of subducting slab in response to the main shock, although the hypothesis requires future investigation.
More information:Eric Kiser et al, Lower Mantle Seismicity Following the 2015 Mw 7.9 Bonin Islands Deep‐Focus Earthquake,Geophysical Research Letters(2021).DOI: 10.1029/2021GL093111
Research from BYU professor Paul Caldarella found that when teachers praise students more often than correcting them behavior improves dramatically. Credit: Jaren Wilkey/BYU
Students speaking out of turn, texting, telling rude jokes, falling asleep in class, making distracting gestures—managing these behaviors is all in a day's work for many middle school teachers, who shepherd adolescents through some of their most trying years. Add in the disruptions of a global pandemic to exacerbate student anxiety and depression, and this year middle school teachers may find themselves with more challenging behaviors to address than ever before.
But a recent BYU paper points out the power of focusing on the positive in sixth through eighth grade.
The study found that when middle school teachers praised students at least as often as they reprimanded them, class-wide on-task behavior improved by 60–70%. Students at high risk for emotional and behavioral disorders were also more likely to be on task, and their classroom marks went up by a full letter grade, compared to high-risk students in classrooms where teachers rarely offered praise. While there was no magic ratio, when teachers praised students more often than correcting them, or even stopped reprimanding completely, behavior improved dramatically—every bit of praise counts.
"With middle school students, we really want to emphasize praising over reprimanding," said BYU David O. McKay School of Education professor Paul Caldarella. "Especially if you have a student who is depressed, anxious, angry or dealing with any kind of emotional difficulty, the more you can praise and the less you reprimand, the better outcomes you're likely to see."
Caldarella and his colleagues Ross Larsen and Leslie Williams at BYU and Howard Wills at the University of Kansas conducted the study as a follow up to their previous research in elementary school classrooms, where they similarly found that the more teachers praised than reprimanded, the more students stayed on task. However, in the new research they found that the results were even more profound in middle schools, with praise producing double the improvement in on-task behaviors compared to elementary classrooms.
The more powerful effect may be due to adolescents' unique developmental needs and the challenges they typically face, such as hyperactivity, anxiety or exposure to bullying.
"As students get older, we often just expect that they're going to be more mature and do what's expected of them," explained Caldarella. "But they actually still need the same kind of reminders as elementary students. And any kind of negative comment made publicly to image-conscious teenagers, who are trying to establish their identity and peer relationships, is likely to make them shut down or get aggressive. So, it's better to praise publicly and correct in private."
For their study, the researchers observed 28 classrooms across five middle schools. In their baseline observations, they noted that teachers gravitated toward reprimanding statements—such as with negative comments or harsh redirections—four to nine times as often as they used praise statements, perhaps because it's human nature to notice inappropriate behavior more easily than appropriate behavior.
After initial observations, the researchers trained half the teachers to pause every few minutes to scan the classroom and praise students behaving well in the moment. For example, a teacher might say, "I like the way you're on task" or "I like the way you raised your hand to ask a question, which is really helpful for me as a teacher." Once trained, most of the teachers were able to implement at least a 1:1 ratio of praise to reprimands. The observers then examined students' on-task behavior and grades in the trained teachers' classrooms as well as those in the control classrooms.
The study's findings about the power of praise hold much promise for teachers hoping to improve learning outcomes and create a better experience for both students and themselves.
"Especially with students coming back from a year grappling with COVID, it's really going to be important to try to focus on the positives this year," Caldarella noted. "If you go into a classroom where there's plenty of praise, you feel better and want to be there, and you behave accordingly."
More information:Paul Caldarella et al, Effects of Middle School Teachers' Praise-to-Reprimand Ratios on Students' Classroom Behavior,Journal of Positive Behavior Interventions(2021).DOI: 10.1177/10983007211035185
Some animals, such as lizards, tortoises and insects, will encounter thermal stress as aresult of climate change. In a recent paper, researchers from South Africa and Australia provide several tools to validate and improve indices that determine the vulnerability of these animals to climate warming. Credit: Dr Susana Clusella-Trullas
It is not easy to predict how animals—from insects to fish—are going to respond to climate change and especially extremes of temperature. This lack of understanding hinders our ability to predict the vulnerability of these animals to climate change.
"We need to continuously improve our ability to predict and mitigate the effects of climate change. One of the ways we can do this is by gaining a better understanding of howanimalsrespond to climate change, and incorporating anyrelevant informationinto risk metrics," says Dr. Susana Clusella-Trullas, a climate change scientist in the Department of Botany and Zoology at Stellenbosch University (SU).
She leads a team of scientists from SU and the University of Melbourne in Australia, and together they have made several proposals on how to improve the current, widely adopted thermal vulnerability index in a recent publication in the high profile journal Trends in Ecology and Evolution.
She says that forecasting the vulnerability of species to climate change requires the right tools for the job and knowing which tools to apply in a specific situation is a challenging enterprise.
The current vulnerability indices are based on the direct influence of climate variables, mostly temperature, on the performance of organisms: "They measure the extent to which performance limits, such as the temperatures at which locomotion or growth can no longer be sustained, are likely to be approached or exceeded with climate warming. Managers and practitioners need to be able to quickly grasp the potential pros and cons of the main approaches to inferring climate change risks. With the right tools and indices of climate change vulnerability, this will allow them to make better decisions, mitigate undesirable impacts, and plan accordingly for the conservation of threatened species," she explains.
Some animals, such as lizards, tortoises and insects, will encounter thermal stress as result of climate change. In a recent paper, researchers from South Africa and Australia provide several tools to validate and improve indices that determine the vulnerability of these animals to climate warming. Credit: Dr Susanna Clusella-Trullas
Yet there remains great debate and little consensus on how best to go about achieving this and the diverse array of metrics and approaches available can be overwhelming. Knowing which tools to select, when to use them and what interpretations can be made, is not straightforward and can lead to confusion in the scientific literature, which in turn trickles back to public uncertainty and slows down effective policy-making.
The team of authors argue that there are many implicit and often untested biases in current thermal indices designed to measure climate change vulnerability. These biases extend across how the thermal landscape is characterized to quantify environmental stress experienced by animals and how they respond, from a behavioral or physiological viewpoint, to more frequent and severe warming.
"It is very hard to devise a test of vulnerability in a laboratory test tube that accurately reflects what happens in nature where animals can adapt to a stress," says Prof Ary Hoffmann from the University of Melbourne. "Yet we often make conclusions about vulnerability based on such assessments." Their paper further goes on to describe approaches to validate vulnerability index applications and discusses key issues to be considered in further developing these indices.
More information:Susana Clusella-Trullas et al, How useful are thermal vulnerability indices?,Trends in Ecology & Evolution(2021).DOI: 10.1016/j.tree.2021.07.001
Scientific research has shown that sexuality exists on a spectrum. But how certain are people about where they fit on it? A new University of Sydney study suggests that people's reported sexual orientation can change after reading about the nature of sexual orientation.
Published in peer-reviewed journal, Nature'sScientific Reports,the study found that a significant number of heterosexual people report being less exclusive in theirsexual orientationas well as more willing to have same-sex experiences after reading one of two 1-page informational articles.
Lead author, Dr. James Morandini, said: "Did we change people's sexual orientation via our interventions? Surely not. I think our study may have changed how people interpreted their underlying sexual feelings. This means two people with identical sexual orientations could describe their sexual orientation quite differently, depending on whether they have been exposed to fluid or continuous ways of understanding sexuality."
One informational article read by participants suggested that scientific research has found that there are many gradations of sexual attraction towards men and women, and people can fall anywhere along the continuum, from exclusive attraction to men to exclusive attraction to women. Another informational article showed that sexual orientation can change overtime, thus can be fluid.
All participants self-identified as "straight" before the study began. Compared to a control group, after reading the first article, participants were 28 percent more likely to identify as non-exclusively heterosexual, and 19 percent indicated they would be more likely to be willing to engage in same-sex sexual activities. Overall, the rate of "non-exclusive heterosexuality"' more than quadrupled after this activity. Similar, albeit weaker, effects were found when people read that sexual orientation is better characterized as fluid rather than stable throughout life.
The study's senior author, Associate Professor Ilan Dar-Nimrod from the School of Psychology, said: "This is not that surprising given that 'non-exclusive heterosexuals' (as opposed to bisexual, gay or lesbian individuals), although being the biggest same-sex attracted group, are not well captured in our society's representations and even vernacular."
He added: "Given the social value that our society attach to these labels, however, such a shift may have far-reaching implications. It also suggests that certain level of same-sex sexual attraction may be much more common than previously estimated."
Methodology
A national Australian sample of 460 individuals (232 women, 228 men) who identified as "straight" prior the study took part in an online panel study.
They were instructed to read an article that suggested that scientific research found one of the following:
There are many gradations of sexual attraction towards men and women and people can fall anywhere along the continuum from exclusive attraction to men to exclusive attraction to women.
Sexual orientation exists in three discrete, non-overlapping categories: gay, bisexual, and straight.
Sexual orientation can change throughout one's lifetime.
Sexual orientation is stable once a person identifies which gender they are attracted to.
Control (no discussion of sexual orientation but instead discussing global warming).
They were then asked to rate their sexual orientation on a 9-point scale from exclusively heterosexual (1) to exclusively homosexual (9) and provide information on how certain they are about their sexual orientation and how willing they are to engage in same-sex sexual encounters.
More information:James S. Morandini et al, Exposure to continuous or fluid theories of sexual orientation leads some heterosexuals to embrace less-exclusive heterosexual orientations,Scientific Reports(2021).DOI: 10.1038/s41598-021-94479-
A submerged coconut palm on Kadavu Island, Fiji. Credit: Ethan Daniels/shutterstock
The small boat sliced its way through the waveless ocean. The Fiji air was warm and still, the silhouettes of distant islands like sentinels watching our progress. It seemed a perfect day to visit the Solo Lighthouse and the "drowned land" reputed to surround it.
As we entered the gap through the coral reef bordering the Solo Lagoon, we all removed our headgear and bowed, clapping gently with cupped hands to show our respect to the people locals say live on the land beneath the sea.
The Solo Lagoon lies at the northern extremity of the Kadavu island group in the south of Fiji. In the local dialect, solo means rock, which is all that is left of a more extensive land that once existed here. Ancient tales recall this land was abruptly submerged during an earthquake and tsunami, perhaps hundreds or even thousands of years ago.
Our boat raced on, towards the lighthouse built on remnant rock in 1888. The people with me, from Dravuni and Buliya islands, told how on a still night when they come here to fish, they sometimes hear from beneath the lagoon the sounds of mosquitoes buzzing, roosters crowing and people talking.
Every local resident learns strict protocols upon entering the realm above this underwater world … and the perils of ignoring them. It is believed if you fail to slow and bow as you enter the Solo Lagoon, your boat will never leave it. If you take more fish from the lagoon than you need, you will never take your catch home.
It is deceptively easy to ridicule such beliefs in underwater worlds but they likely represent memories of places that really were once submerged. Several groups of people living throughout Fiji today trace their lineage back to Lomanikoro, the name of the drowned land in the Solo Lagoon. Though there is no written record of the event, it is believed submergence reconfigured the power structures of Fijian society in ways that people still remember. Similar traditions are found elsewhere.
In northern Australia, many Aboriginal groups trace their lineage to lands now underwater. A story told decades ago by Mangurug, a Gunwinggu elder from Djamalingi or Cape Don in the Northern Territory, explained how his people came from an island named Aragaládi in the middle of the sea that was later submerged. "Trees and ground, creatures, kangaroos, they all drowned when the sea covered them," he stated.
Other groups living around the Gulf of Carpentaria claim their ancestors fled the drowning land of Baralku, possibly an ancient memory of the submergence of the land bridge connecting Australia and New Guinea during the last ice age.
In northwest Europe, meanwhile, there are countless stories of underwater lands off the coast where bells are said to toll eerily in drowned church steeples. Such stories abound in Cardigan Bay, Wales, where several "sunken cities" are said to lie. In medieval Brittany, in France, fisher-folk in the Baie de Douarnenez used to see the "streets and monuments" of the sunken city named Ys beneath the water surface, stories of which abound in local traditions.
Indeed in many cultures across the world there are stories about underwater worlds inhabited by people strikingly similar to ourselves, cities where benevolent bearded monarchs and multi-tentacled sea witches organize the lives of younger merfolk, many of whom aspire to become part of human society. Fantasy? Undoubtedly. Arbitrary inventions? Perhaps not.
Such ideas may derive from ancient memories about submerged lands and the peoples who once inhabited them.
And if we allow that some of these stories may actually be founded on millennia-old memories of coastal submergence, then they may also have some practical application to human futures. For coastal lands are being submerged today; birthplaces in living memory now underwater.
Coast line near Tresaith, Cardigan Bay. Credit: Shutterstock
Context
In the 200,000 years or so that we—modern humans—have roamed the earth, the level of the ocean, which currently occupies over 70% of the earth's surface, has gone up and down by tens of meters. At the end of the last great ice age, around 18,000 years ago, the average ocean level was 120 meters or more lower than it is today.
As land ice melted in the aftermath of the ice age, sea level rose. Coastal peoples in every part of the world had no choice except to adapt. Most moved inland, some offshore. Being unable to read or write, they encoded their experiences into their oral traditions.
We know that observations of memorable events can endure in oral cultures for thousands of years, plausibly more than seven millennia in the case of Indigenous Australian stories of volcanic eruptions and coastal submergence. So how might people's memories of once populated lands have evolved in oral traditions to reach us today?
Initially they would have recalled the precise places where drowned lands existed and histories of the people who had occupied them. Perhaps, as time went on, as these oral tales became less convincing, so links were made with the present. Listen carefully. You can hear the dogs barking below the water, the bells tolling, the people talking. You might even, as with Solo, embed these stories within cultural protocols to ensure history did not disappear.
Traditions involving people of the land interacting with their submarine counterparts are quite old; the Greek story of a merman named Triton is mentioned in Hesiod's Theogony, written almost 3,000 years ago. In Ireland, there are stories hundreds, perhaps thousands, of years old that tell of high ranking men wedding mermaids, begetting notable families, and even giving rise to taboos about killing seals, whom these mermaids regarded as kin.
Stories of people occupying undersea lands also abound in Indigenous Australia. They include those about the yawkyawk (or "young spirit woman" in the Kundjeyhmi language of western Arnhem Land), who has come to be represented in similar ways to a mermaid.
Like mermaids in Europe, Australian yawkyawk have long hair, which sometimes floats on the ocean surface as seaweed, and fish tails.
In the central Pacific islands of Kiribati, meanwhile, it was once widely believed worlds existed parallel to the tangible one we inhabit. Entire islands moved between these, wandering through time and space, disappearing one day only to reappear some time later in a different place. Humans also moved between these worlds—and I suspect this was once a widespread belief of people occupying islands and archipelagos.
Sometimes the inhabitants of these worlds were believed to be equipped with fish tails, replaced with legs when they moved onshore. An ancient ballad from the Orkney Islands (Scotland), where such merfolk are often called silkies, goes:
"I am a man upon the land / I am a silkie in the sea."
At one time, the people of the Aran Islands (Galway, Ireland) would believe they had spotted the island of Hy-Brasail far to the west; scrambling to reach it in their boats. No-one ever did. On the other side of the world, the fabulous island named Burotukula that "wanders" through Fiji waters is periodically claimed to be sighted off the coast of Matuku Island.
Matuku Island, Fiji. Credit: Shutterstock
Anxiety and solutions
In oral societies, such as those that existed almost everywhere a thousand years ago, knowledge was amassed and communicated systematically by older people to younger ones because it was considered essential to their survival. Much of this knowledge was communicated as narrative, some through poetry and song, dance, performance and art.
In harsh environments, where water and food were often scarce, it was vital to communicate knowledge fully and accurately. Australia provides excellent examples, where Indigenous law was cross-checked for completeness and accuracy when transmitted from father to son.
Part of the law considered essential to survival was people's experiences of life-altering events. This included bursts of volcanic activity and the multi-generational land loss that affected the entire Australian fringe in the wake of the last ice age, reducing land mass by around 23%.
Recent research has shown some ancient Indigenous Australian "submergence stories" contain more than simply descriptions of rising sea level and associated land loss. They also include expressions of people's anxiety.
For instance, a story told in 1941 by Sugar Billy Rindjana, Jimmy Moore and Win-gari (Andingari people) and by Tommy Nedabi (Wiranggu-Kokatato) recalled how, millennia earlier, their forebears living along the Fowlers Bay coast in South Australia "feared the sea flood would spread over the whole country."
These stories also talk about people's practical responses to try to stop the rising waters. The Wati Nyiinyii peoples from the Nullarbor Plain in Western Australia once "bundled thousands of [wooden] spears to stop the ocean's encroachment" on the lands that once existed below the Bunda Cliffs.
In a story told by the Gungganyji people of the Cairns district in northeast Australia, they heated boulders in a mountain-top fire, then rolled these into the face of the encroaching ocean to stop its rise.
Today the ocean surface along most of the world's coasts is rising faster than it has for several thousand years. It is placing growing stress on coastal societies and the landscapes and infrastructures on which they have come to depend. Anxiety is building, especially in the face of scientific projections involving sea-level rise of at least 70 cm by the end of this century.
We are responding with practical solutions, building hard structures such as walls and wooden palisades along coastlines. We look to science to curb climate change but many people still feel anxious and powerless.
Our ancient ancestors, confronted with a seemingly unceasing rise in the ocean surface—and associated loss of coastal lands—also felt anxiety and built structures. And, as some people do today, many almost certainly sought spiritual remedies too. Of course we know little about the latter, but there are clues.
In many places along the coasts of Australia and northwest Europe, there are stone arrangements, ranging from simple stone circles to the extraordinary parallel "stone lines" at Carnac in France, kilometers long.
These stone lines, built more than 6,000 years ago have been interpreted by French archaeologists as a "cognitive barrier" intended to stop the gods interfering with human affairs, specifically to stop the rapid and enduring rise of the sea level along this part of the Brittany coast. Ritual burials of people and valuables along the shore in northwest Europe may once have served a similar purpose.
We can take hope from our ancestors' experiences with rising sea level. Most people survived it, so shall we. But the experience was so profound, so physically and psychologically challenging, that the survivors kept their memories of it alive as stories passed on from one generation to the next. Their stories became enduring oral traditions—intended to inform and empower future generations. And to show us that the past is not without meaning; it is not irrelevant to our future.
For many teachers, news coverage of education seems to be unrelentingly negative. They say this is particularly noticeable in reporting of results of standardized tests such as NAPLAN and the OECD's Programme for International Student Assessment (PISA), which seems to place most of the blame for perceived problems on them.
Australian students have reportedly been falling behind many other countries in literacy and numeracy in the PISA tests, for years. The results are nuanced, but the reporting often isn't. For instance, Australia's score in science in PISA 2015 was 510, significantly above the OECD average of 493. But the reports tend to focus on areas where we have fallen behind than other countries, rather than where Australia may have done well.
In my interviews with Australian schoolteachers, most of the participants accepted standardized testing was necessary. But they opposed the results of NAPLAN testing being released due to the inevitable comparisons of student progress and schools in the related news coverage.
A growing body of research from Australia and overseas suggests teachers' perceptions about education news are justified. Education news focuses on student discipline, teacher quality, comparisons of testing results and standards. All these subjects tend to be framed negatively.
While individual success stories of students, teachers or schools are celebrated, they are usually portrayed as the exception.
What teachers say
In my 2017 study, I interviewed 25 teachers from around Australia about their perceptions of news reporting of education—88% of participants considered it to be predominantly negative.
A teacher from a Queensland public school acknowledged that from "time to time" good news stories about schools did appear but said most the coverage was "shock, horror, look at all these dreadful things that are happening in the school system."
The mostly negative portrayal presented in major metropolitan news outlets was unfair and inaccurate, according to the teachers, and the positive elements tended to be overlooked.
One used the reporting of testing results as an example: "When the NAPLAN data was published our federal minister had quite a lot of material published about how we were slipping down the league tables, but when our 15 year-olds were rated the fifth top all rounders [in the PISA tests] […] that barely got a squeak."
Several participants referred to the prevalence of news coverage that portrayed teachers as low achievers. "We continually hear about low entrance scores to get into teaching. We continually hear about teacher under-performance."
Some of those interviewed believed teachers were treated differently to other professionals in news coverage, and were subjected to greater scrutiny and pressure. "What I do each day is questioned at every level," one teacher said.
A particular frustration related to news coverage that did not capture the true nature of contemporary teaching. A principal argued there was "an absolute failure" on the part of the news media to recognize the complexity of teachers' work. She said: "Teachers are not going to school, they are going to work and it's highly complex and highly technological."
Other Australian research has found some teachers have named misleading and negative reporting of education as a factor in their decision to quit teaching.
Parents feel the same way
Our new research has found some Australian parents share teachers' views. Of the survey group of 268 teachers and 206 parents, 85% of teachers and 74% of parents considered news coverage of the Australian education system to be generally negative.
Half of the parents surveyed reported feeling demoralized by such reporting. For teachers, that figure increased to 81%.
Significantly, we also found positive news can be inspiring. Around 64% of both teachers and parents reported they feel inspired "quite a bit" or "a lot" when they encounter a positive news story about teachers, schools or the education system.
While it is not the role of reporters to appease teachers, the evidence about the predominantly negative nature of education news and teachers' concerns about superficial and inaccurate coverage should be taken into account. And it can just be a matter of shifting the angle.
Readers turned off by negative news
There are also sound commercial reasons for rethinking the approach to reporting education. In covering education, news editors are aiming to appeal to the high numbers of parents among their audiences.
Our research suggests parents are interested in education news. But they may be less likely to engage the more negative it is. We know from other research that the most common reason people avoid news is because it has a negative impact on mood.
So, if editors want to attract readers with educationnews, coverage that includes more positive elements could achieve more success.
U of A ecologist Stephanie Green gets up close with a lionfish for her research on invasive species. Green helped create a tool to predict which native fish may be most vulnerable to existential threats from the voracious invader. Credit: Stephanie Green
Coastal countries have between two and five years to act to protect native fish species once voracious lionfish arrive in their waters, according to a University of Alberta ecology professor who helped create a tool to predict which fish are in danger.
"There's lots of concern about what their impacts will be and also which species are at risk," said Stephanie Green, Canada Research Chair in Aquatic Global Change Ecology and Conservation in the Faculty of Science. "They're the perfect invader."The lionfish, originally a popular aquarium species native only to the Pacific and Indian oceans, is now a highly invasive species throughout the Atlantic Ocean and Mediterranean Sea, where they are known to consume hundreds of native fish species.
Getting ahead of the invaders
Lionfish are gape-limited predators, which means they swallow their prey whole, and can grow to a formidable half-meter long. They have no natural predators in the Atlantic, thanks in part to 18 poisonous spines, and can devastate a population of their coral reef prey—killing as much as 95 percent—in just a couple of years.
"We can look in lionfish stomachs to see what they're eating, but often that information comes too late to protect the native species," Green said.
"Instead, we need to anticipate what lionfish are likely to eat as they spread to new areas and encounter a totally new diet, based on their food preferences."
To create the framework identifying vulnerable fish species, Green joined forces with Christi Linardich, a scientist from the Global Marine Species Assessment team associated with the International Union for Conservation of Nature, which publishes the "IUCN Red List of Threatened Species"—assessments of the extinction risk for virtually every wildlife species in the world.
"We literally started with every Caribbean fish that's out there," Linardich said.
Together with U of A graduate student Cole Brookson, Green and Linardich worked to narrow the field to those species that live in reef systems where lionfish typically hunt.
In classifying the relative vulnerability of fishes, the team looked for traits known to influence susceptibility to lionfish predation, including body shape, water column position and aggregation behavior, and habitat overlap as well as the degree of geographic range restriction.
Identifying the most vulnerable species
The team identified 77 Caribbean and 29 Brazilian species as highly vulnerable.
Species of particular concern are the social wrasse—a fish known only from shallow waters around a small island chain in central Belize, where lionfish were first sighted in 2010—and the salmon-spotted jewelfish, known only from coral reefs off a single island off of Brazil, where lionfish have not yet invaded but are predicted to soon reach.
Green noted many of the vulnerable species are found below scuba diving depths, beyond 120 feet deep, and only known to science from very few specimens.
"If lionfish take hold in high numbers where these species occur, they could be lost before we even know much about them," she said.
With the framework in hand, the team identified hot spots on the lionfish path. Jurisdictions include Belize, the Bahamas and Curaçao as well as several locations in Brazil: the Fernando de Noronha Archipelago, Rocas Atoll and the coasts of São Paulo and Santa Catarina states.
"Brazil is a really big deal because they have a number of what we call endemic fish, which means that they're not found anywhere else, and many are restricted to small oceanic islands where major threats can be catastrophic to a species' continued existence," said Linardich.
The study said implementing control measures at the invasion front two to five years before lionfish reach peak density could avert species' extinction.
"Lionfish invasion really is a global issue," Green said. "There are more than 30 countries being impacted by this species. As the invasion intensifies and expands, there is an urgent need to identify species most at risk."
Current strategies to control lionfish are mainly through volunteer efforts to hunt them, lionfish derbies and the creation of lionfish fisheries.
"One of the things we have in our favor is lionfish are actually very tasty fish," Green said.
The study, "Trait-based vulnerability reveals hotspots of potential impact for a global marine invader," was published in Global Change Biology.
More information:Christi Linardich et al, Trait‐based vulnerability reveals hotspots of potential impact for a global marine invader,Global Change Biology(2021).DOI: 10.1111/gcb.15732
