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)
Wednesday, June 22, 2022
BAD KARMA BAD ROAD SAFETY
Mountain lion P-54 is killed by vehicle four years after her mother died on the same road
by Christian Martinez
Credit: Unsplash/CC0 Public Domain
A mountain lion was struck and killed by a vehicle Friday in the Santa Monica Mountains, not far from where her mother was killed in a 2018 crash, the National Park Service said.
P-54, born in 2017, was struck around 9:30 a.m. on Las Virgenes Road between Piuma Road and Mulholland Highway, becoming "the latest grim statistic for regional mountain lions," the park service said in an Instagram post.
The lion will be taken to the California Animal Health and Food Safety Lab in San Bernardino for a full necropsy.
She is the 29th mountain lion killed by a vehicle since 2002 in the park service's cougar study area—which includes the Santa Monica Mountains, Simi Hills, Griffith Park and the Santa Susana and Verdugo mountains—including 10 lions that had been collared and tracked by parks officials.
Underscoring the ever-present danger mountain lions face trying to cross roads and freeways in the area, P-54's mother was killed on the same road in January 2018, and her son was killed on the 405 Freeway just two months ago.
Her mother, P-23, was found dead farther south from where P-54 was killed, where Las Virgenes Road becomes Malibu Canyon Road.
At the time, P-54 was a year old and "at the early end of when kittens typically leave their mother," the park service said. P-23 was 5 1/2 years old when she was killed.
P-97, one of P-54's five offspring born in 2020, was struck and killed on the 405 Freeway near the Getty Center in April.
"He was 18 months old and had recently dispersed from his mother, P-54," the park service said.
In May 2020, P-54 gave birth to a litter of three kittens, which researchers believe did not survive. She gave birth to P-97 and P-98 in October 2020.
P-97 was struck and killed a day before work began on a wildlife bridge over the 101 Freeway in Agoura Hills aimed at encouraging safe crossings for mountain lions and other wildlife that are genetically isolated by the freeway.
The bridge, funded by $87 million in donations, is expected to be completed in 2025.
L.A.'s mountain lions have been confined to small territories by the region's roads and freeways, leading to the lowest genetic diversity documented for the species aside from the critically endangered Florida panther.
Because of the resulting inbreeding, vehicle deaths, urban encroachment and other threats, there is an almost 1 in 4 chance the cats could become extinct in the Santa Monica and Santa Ana mountains within 50 years, according to some recent studies.
Ortho-mosaic on 28 August 2021 (left panel), hillshade generated from the DEM on 28 August 2021 (middle panel), and changes in elevation between 24 June and 28 August 2021 (right panel). Glacier ablation was monitored using ablation stakes (S1–S3). Credit: Wang Feiteng
Glaciers are experiencing fast and significant changes under global warming. Glacier shrinkage significantly impacts global sea level, regional water cycles, ecosystems, and natural hazards.
Many studies have considered glacier changes and the mechanisms driving such changes. However, few studies have focused on mitigating glacier ablation.
Recently, a research team from the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences conducted the evaluation of glacier cover efficiency for melt reduction on the Urumqi Glacier No. 1, Tien Shan, China.
Their results were published in Remote Sensing.
By combining two high-resolution digital elevation models derived from terrestrial laser scanning and unmanned aerial vehicles, albedo, and meteorological data, the researchers quantified the glacier ablation mitigation under three different cover materials.
The results showed that material-covered areas could slow down glacier melting by approximately 29–56% compared with uncovered areas. The researchers also found that the nanofiber material showed higher efficiency (56%) than the geotextiles used in the experiment.
The method of artificial reduction of glacial ice melt provides a scientific and practical basis for decision-making on mitigating and adapting to climate change.
More information:Shuangshuang Liu et al, Quantifying the Artificial Reduction of Glacial Ice Melt in a Mountain Glacier (Urumqi Glacier No. 1, Tien Shan, China),Remote Sensing(2022).DOI: 10.3390/rs14122802
Populations of Pocillopora aliciae are thriving in coastal Sydney. Credit: John Sear
Worsening environmental pressures, such as higher sea temperatures, are causing the catastrophic loss of coral cover around the globe. As the waters of the Great Barrier Reef warm, subtropical corals are heading south in search of cooler waters.
Sydney has recently become home to a new subtropical coral, which raises a significant question: could Sydney be a refuge for corals displaced by climate change?
The answer, say coral reef researchers at the University of Technology Sydney (UTS), is yes … but.
A new study, published in Coral Reefs, analyzed the metabolism of these new corals under existing and future warming scenarios and found the invading subtropical corals will survive and thrive in coastal Sydney.
Study leader Dr. Jen Matthews, of the Future Reefs Program at UTS, says warming could spell trouble for existing Sydney coral species.
"While we found these corals possess the machinery to withstand large changes in temperature, those temperatures could kill the existing corals in Sydney. This is incredibly important when we consider the future of Sydney's precious ecosystems," Dr. Matthews says.
"Coastal Sydney falls in the temperate climate zone, so the establishment of subtropical coral populations raises some interesting questions, such as how can they survive at the edge of existence? We are continuing to examine how corals can live and breed in temperate, or suboptimal, environments, and how we might use this knowledge to help us to protect Australia's reefs into the future.
"The ecological services and economic revenue of the Sydney marine environment make it a very valuable ecosystem but it is under continuous threat from climate change and urbanization, causing increased stormwater inflows and habitat modification."
However, co-investigator Dr. Brigitte Sommer (UTS) says there may be exciting upsides—increasing the biodiversity and complexity of Sydney's marine ecosystems could bring benefits in terms of refuge for reef fish, coral crabs and potentially other coral species.
More information:Raúl A. González-Pech et al, Physiological factors facilitating the persistence of Pocillopora aliciae and Plesiastrea versipora in temperate reefs of south-eastern Australia under ocean warming,Coral Reefs(2022).DOI: 10.1007/s00338-022-02277-0
As staghorn coral declines along Florida coast, planting project tests restoration plan
by Olivia Lloyd
Credit: CC0 Public Domain
Just 150 fragments of staghorn coral planted off Florida's shore might give new hope to the state's endangered reefs.
A boat carrying those fragments set off Tuesday afternoon in Jupiter, marking the beginning of a study on the temperature tolerance of coral on Florida's northern reef tract.
"This is the farthest north that this species has been out-planted," said Shelby Thomas, the founder and CEO of the Ocean Rescue Alliance. "This will really help give us more insight in the future if it's a suitable site to expand doing coral restoration efforts in Florida, and seeing if the species can survive further north."
The Ocean Rescue Alliance is a nonprofit marine conservation and restoration organization that works in coral restoration and the creation of artificial reefs. It operates as far south as the Keys and now as far north as Jupiter.
They are working with the University of Miami to conduct research on the coral's tolerance to warmer water. The team will be monitoring the coral and collecting tissue samples on a monthly basis. They are also working with Palm Beach County and the Florida Fish and Wildlife Commission in the planting effort.
Rob Bremer, a masters student at the University of Miami, is working on this project with the Ocean Rescue Alliance. He said the deterioration of the coral off the coast of Florida makes these kinds of studies necessary.
"We lose a lot of corals every year, and the rates of reproduction are dropping as well, which is a pretty scary sign," Bremer said. "So between that and SCTLD [stony coral tissue loss disease] killing a ton of corals a year … it's not looking really good for corals both in Florida and kind of worldwide."
According to research published by the University of Florida, climate change, human stressors and stony coral tissue loss disease have greatly reduced the staghorn coral's presence in southeast Florida. A 2020 study found that staghorn coral populations have declined over 90% since the 1970s. As staghorn coral falters in its usual habitat range of the Caribbean and southeast Florida, Bremer and Thomas are testing how well it can survive at the edge of its northernmost range.
"This project has a lot of potential to prove that corals can expand outside of their natural habitats or habitat ranges," Bremer said. "If these corals survive and continue to prosper as they have, I think that assisted migration northwards...could be very much incorporated into our restoration focuses."
The Ocean Rescue Alliance also plants artificial reefs through its 1000 Mermaids Project, which aims to eventually place 1,000 artificial reefs in Florida waters in the form of mermaid sculptures. Thomas calls this project "eco art," creating habitat for marine life and a spot for fishers and divers. Currently the team's largest artificial reef consists of 35 mermaid structures off West Palm Beach.
"We can actually make a sculpture of any person or logo and make them into an artificial reef that creates fish habitat and can help create structure on the seafloor," Thomas said. "All of our sculptures still have a habitat component, so they're not just sculptures that don't add any value to the environment."
According to the National Oceanic and Atmospheric Administration, artificial reefs can have a positive ecological impact when done right. They can divert human traffic from natural reefs and provide shelter for fish and other species that need a physical habitat. However, they could potentially provide a habitat for invasive species or damage natural habitats.
"Typically, I am an advocate for artificial reefs," Bremer said. "I think that one of the biggest things they can do is raise awareness for actual reefs, and for just natural beauty. They can also pull a lot of diving pressure off of natural reefs."
This July, the Ocean Rescue Alliance plans to plant 30,000 corals near Hollywood.
"That's really going to lead way to a whole other variety of coral restoration research and community engagement," Thomas said. "So we're really looking forward to expanding our initiatives and public engagement as well."
Bremer agreed that public engagement may become increasingly important in conservation efforts.
"At the end of the day, we're probably never going to be able to do enough as scientists to completely turn the tide against global warming and other anthropogenic factors," he said. "So I think that we as a scientific community also need to become maybe more well-rounded than we're typically used to and work on engaging the public and getting our voices heard throughout policies as well."
2022 South Florida Sun Sentinel. Distributed by Tribune Content Agency, LLC.
Ovum‑in‑ovo egg suggests titanosaur's reproductive biology was more like birds than reptiles
Field photograph and microscopic images of the eggshell from egg number C showing oospecies Fusioolithus baghensis characterized by fan-shaped shell units with arching growth lines and basal end cap units. (a) The ovum-in-ovo egg with the boxed area showing the region from where the specimen was extracted. (b) Radial Scanning Electron Microscope (SEM) photomicrograph of the eggshell showing partially preserved fan-shaped shell unit. (c) Photomicrograph of the radial thin section of the eggshell under polarized light microscopy showing partially preserved shell units (see black arrow) and characteristic swollen basal cap units (see red arrow). (d) Photomicrograph of the radial thin section of the eggshell under polarized light microscopy exhibiting fused shell units and growth lines (see black arrow) and swollen basal cap (see red arrow). Credit: Scientific Reports (2022). DOI: 10.1038/s41598-022-13257-3
A trio of researchers, two with the University of Delhi and a third with the Dhar District, Higher Secondary School, has found the first-ever example of an ovum-in-ovo dinosaur egg. In their paper published in Scientific Reports, Harsha Dhiman, Guntupalli Prasad and Vishal Verma describe the dinosaur egg they found and why they believe it suggests at least one type of dinosaur reproduction was more like modern birds than reptiles.
The fossilized egg was found in the Dhar district, Madhya Pradesh, in a central western part of India and was in good enough condition to allow the researchers to see that it was ovum-in-ovo, or egg-in-egg. In birds, such eggs are created when one egg is pushed back into the body of the bird and into the reproductive system, where it becomes embedded in another egg still in the process of forming. Such egg formations are not seen in reptiles; thus, the find suggests that the reproductive system of the dinosaur that laid the egg, a titanosaur, was more similar to modern birds than to reptiles. Dating of the nesting site where the egg was found showed it be from approximately 66 to 100 million years ago.
The egg was found at a location called Nest p7 at the dig site where several other dinosaur fossils, including eggs, have been found—all titanosaurs. Fossils of such dinosaurs, which were a type of sauropod, are widespread, found on all modern continents. Prior evidence has also shown that the titanosaurs were thriving right up until the extinction event that wiped them out, along with all the other non-bird dinosaurs.
The researchers noted that the fossilized egg had two complete shells, one inside the other, separated by a small gap—a clear sign that it was ovum-in-ovo. The researchers were able to capture cross-sectional images of the egg and found it to be remarkably similar to ovum-in-ovo found in modern birds. They suggest that the dinosaur was part of a group that had evolved to lay eggs sequentially and that ovum-in-ovo is not exclusive to birds.Non-avian dinosaur found to have laid blue eggs
More information:Harsha Dhiman et al, First ovum-in-ovo pathological titanosaurid egg throws light on the reproductive biology of sauropod dinosaurs,Scientific Reports(2022).DOI: 10.1038/s41598-022-13257-3
The illustrated forminifer species Uvigerina peregrina was recovered from a sample from Peruvian oxygen minimum zone in 2017. Credit: Jan Michels
In the context of climate change, the phenomenon of oxygen-depleted areas in the ocean has become a focus of scientific attention in recent years. These areas, known as oxygen minimum zones (OMZ), are located in the Indian Ocean or off the Peruvian coast in the Pacific, for example. Depending on water depth, little or no oxygen is found there.
In a new study, a transdisciplinary research team with the participation of Kiel University and GEOMAR Helmholtz Centre for Ocean Research Kiel was able to gather previously unknown details about the origin and adaptation of certain unicellular organisms to these special environmental conditions and their influence on the marine nutrient cycle: Because their metabolism does not rely on oxygen, numerous species of foraminifera are found in the OMZ. These are unicellular, shell-forming microorganisms that already feature a cell nucleus and thus belong to the so-called eukaryotes.
Their special lifestyle is based on so-called anaerobic respiration or nitrate respiration, in which nitrate available in the water is converted into molecular nitrogen in the absence of oxygen. Nitrogen, as a basic nutrient of all living organisms, is no longer biologically available as a result of this process and is thus lost to the marine habitat. The research team led by Professor Tal Dagan of the Institute of General Microbiology at Kiel University has now been able to prove via genome analyses that the ability of nitrate respiration, still preserved in most foraminifera today, might have originated in a common predecessor around 100 million years ago.
Their analyses also showed that the foraminifera probably rely on bacterial support for a specific step in the process of nitrate respiration, also known as denitrification, and are therefore associated with certain symbiotic bacterial species. The Kiel researchers, who are active in the Kiel Evolution Center (KEC) and the Collaborative Research Center (CRC) 1182 Origin and Function of Metaorganisms, published their results together with international colleagues recently in the journal Proceedings of the National Academy of Sciences.
Dr Christian Woehle (left) and Dr Joachim Schönfeld handling a multicorer during a sampling expedition in Kristineberg, Sweden 2015. Credit: Jan Michels
Nitrate respiration originated millions of years ago
The research team examined sediment samples from the Peruvian OMZ and was able to identify around ten different species of foraminifera living in the seafloor. From previous research almost all of these species are known to be capable of nitrate respiration. The scientists therefore looked for genes that are likely involved in nitrate metabolism.
"Indeed, numerous of these genes were found in our samples from Peru. Since these species have been shown to perform nitrate respiration, we were thus able to provide a causal link between the presence of the genes and their function," says first author Dr. Christian Wöhle, a former member of Dagan's Genomic Microbiology group at Kiel University.
In a next step, the researchers traced back how long ago the evolutionary acquisition of nitrate respiration could have occurred. To do this, they created so-called phylogenetic trees, which visualize the relationships between different species to identify a possible common ancestor. "In this way, we were able to narrow down a time period for three specific groups of foraminifera. All earlier species lacked the genetic equipment for nitrate respiration," Wöhle explains. "Thus, we could reconstruct that they probably go back to a common predecessor that must have developed this trait in the Cretaceous period about 100 million years ago," Wöhle continues.
Some specimens of the studied species Uvigerina striata sieved out of the sediment using sieves of various sizes. Credit: Prof. Tal Dagan
Microbes provide missing metabolic step
In a metagenome analysis of the Peruvian sample material, the researchers also examined the genetic material of all species found to establish possible symbiotic relationships between various foraminifera and bacteria. First, comparisons with foraminifera species from distant locations showed that they are often associated with a similar and stable composition of bacterial species, regardless of geography.
"In our study, we further noticed an association between a particular genus of foraminifera and so-called Desulfobacteria. These bacteria have previously been observed to be colonizers of other groups of foraminifera," said Dr. Alexandra-Sophie Roy, a former member in the Genomic Microbiology group.
Another indication of a symbiotic relationship between these bacteria and the denitrifying foraminifera was found in the form of the so-called NapA gene. In Desulfobacteria, it is responsible for an enzyme that can initiate the start of the multistep process of nitrate respiration.
"Earlier studies showed that precisely this first step cannot be performed by foraminifera themselves. Therefore, it seems plausible that the bacteria take over this part of nitrate respiration, for example by converting nitrate into nitrite that is useful for their hosts, and therefore form a stable symbiosis with the foraminifera," Roy explains.
New insights into global nutrient cycles
"Our work on the origins and evolution of the genetic basis of ancient nitrate metabolism provides us with important new insights to better understand today's global biogeochemical cycles," says Professor Tal Dagan, KEC board member and project leader in the CRC 1182. In particular, she said, the possible involvement of bacteria in nitrate respiration in the oxygen-depleted ocean is an important but so far understudied component that needs further research in the future.
"The accelerating pace of global environmental change requires deepened knowledge of the turnover and distribution of elemental substances in the ocean. Our new results contribute to a better understanding of the impact of climate change on oxygen-dependent nutrient cycles in the ocean and their effects on marine organisms," adds Dr. Joachim Schönfeld from GEOMAR, who was also involved in the study.How nutrients are removed in oxygen-depleted regions of the ocean
More information: Christian Woehle et al, Denitrification in foraminifera has an ancient origin and is complemented by associated bacteria, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2200198119
Mineralogical data across the extinction event. Mineralogical data from (A) Ubara and (B) Akkamori. Quartz (qtz); pyrite (pyr); berthierine (bth); Fe-illite; and frw_s. Credit: Nature Communications (2022). DOI: 10.1038/s41467-022-31128-3
The end-Permian mass extinction is the most severe mass extinction event ever recorded, during which ~80% of marine species went extinct
While the beginning of this extinction event was driven by an extreme and rapid warming event, recovery of both global climate and ecosystems was extremely sluggish. Temperatures remained lethally hot and ecosystems remained depleted for over 5 million years.
Based on our current understanding of how the carbon cycle and climate operates, temperatures ought to have recovered much more quickly.
This delayed recovery stands out from all other known mass extinction events, and has baffled scientists for many years without any real explanation.
A recently released paper published by Nature Communications, "Marine siliceous ecosystem decline led to sustained anomalous Early Triassic warmth," by University of Waikato researchers Terry Isson and Sofia Rauzi from the Earth-Life Interactions (ELI) research group, suggests that the decline of silica secreting marine organisms across this event both exacerbated climate change and was responsible for the 5 million year delay in global temperature recovery.
This provides for the first time, an comprehensive explanation for why it took so long for temperatures to recover to what they were before the mass extinction event.
Clay minerals form in the oceans and in the process release CO2. Clays minerals are fundamentally made up of silica and so cannot form without it. Silica secreting organisms compete for this silica, meaning that a healthy siliceous ecosystem that uses large amounts of silica will act to lower the amount of CO2 released from clay mineral formation.
It is well established that there was widespread loss of silica secreting organisms in the oceans during the end-Permian mass extinction event, and that these organisms did not recover for 5 million years. This research demonstrates, using a carbon cycle model and also mineralogical analysis, that this would have led to increased CO2 release into the atmosphere during this time, keeping temperatures on Earth high for a prolonged period of time.
This research provides the first ever direct evidence that silica secreting organisms play a very prominent role in regulating climate on Earth that has previously never been recognized.Rethinking planetary climate controls
More information: Terry T. Isson et al, Marine siliceous ecosystem decline led to sustained anomalous Early Triassic warmth, Nature Communications (2022). DOI: 10.1038/s41467-022-31128-3
Hackmanite turns purple under UV irradiation, and the color fades back to white in a few minutes under regular white light. This sample is from Greenland. Credit: Mika Lastusaari
While investigating hackmanite, researchers found that it can change color upon exposure to UV radiation repeatedly without wearing out. The results show that the inexpensive hackmanite, which is easy to synthesize, also has high durability and multiple applications.
A research group at the University of Turku, Finland, has been investigating and developing the properties of the hackmanite for almost a decade. Applications such as personal UV monitoring and X-ray imaging have been developed based on hackmanite's ability to change color.
Hackmanite changes its color from white to purple under UV irradiation and eventually reverts back to white if no UV is present. The structural features enabling such repeated changes have so far been unclear. Now, upon investigating three natural minerals—hackmanite, tugtupite and scapolite—the researchers have found the answer.
These color-changing minerals are inorganic natural materials, but there are also organic compounds, hydrocarbons, that can change color reversibly due to exposure to radiation. These hydrocarbons, however, can only change color a few times before their molecular structure breaks down. This is because the color change involves a drastic change in the structure, and undergoing this change repeatedly eventually breaks the molecule.
"In this research, we found out for the first time that there is actually a structural change involved in the color change process, as well. When the color changes, sodium atoms in the structure move relatively far away from their usual places and then return back. This can be called 'structural breathing,' and it does not destroy the structure even if it is repeated a large number of times," reports Professor Mika Lastusaari from the Department of Chemistry at the University of Turku, Finland.
White scapolite turns blue under UV irradiation. The coloration and reversion back to white after the removal of the UV source take only a few seconds, because atoms in the structure move short distances. Scapolite is a rather common mineral. This sample is from Afghanistan. Credit: Sami Vuori
Researchers proved that hackmanite's ability to alternate between white and purple forms is highly repeatable
According to Professor Lastusaari, the durability is due to the strong three-dimensional cage-like overall structure of these minerals, which is similar to that found in zeolites. In detergents, for example, the cage-like structure enables zeolite to remove magnesium and calcium from water by binding them tightly inside the pores of the cage.
These color-changing minerals, all processes associated with the color change occur inside the pores of the zeolitic cage where the sodium and chlorine atoms reside. That is, the cage-like structure allows atomic movement inside the cage while keeping the cage itself intact. This is why minerals can change color and revert back to their original color practically indefinitely," Doctoral Researcher Sami Vuori explains.
Previously, it has been known that scapolite changes color much faster than hackmanite, whereas tugtupite's changes are much slower.
"Based on the results of this work, we found out that the speed of the color change correlates with the distance that the sodium atoms move. These observations are important for future material development, because now we know what is required from the host structure to allow the control and tailoring of the color change properties," says Doctoral Researcher Hannah Byron.
"There were no characterization methods available for the research on color changing minerals, which is why we have developed new methods by ourselves. However, it is difficult to interpret the results unambiguously based on experimental data alone. In fact, we could not have reached the present conclusions without strong support from theoretical calculations, since only the combination of experimental and computational data shows the whole picture. We owe a great many thanks to our collaborator Professor Tangui Le Bahers and his group, who have developed and advanced suitable computational methods to such detail and accuracy that would not have been possible just a few years ago," says Lastusaari.
Tugtupite is a rare mineral, which turns pink when exposed to UV radiation. The return back to white takes several hours, because it requires large atomic movements. This sample is from Greenland. Credit: Sami Vuori
Hackmanite has amazing potential for applications
The Intelligent Materials Research Group at the Department of Chemistry of the University of Turku, led by Lastusaari, has long conducted pioneering research on materials with light and color-related properties, especially on hackmanite. They are currently exploring numerous applications for hackmanite, such as possibly replacing LEDs and other light bulbs with the natural mineral and using it in X-ray imaging.
One of the most interesting avenues that the researchers are currently exploring is a hackmanite-based dosimeter and passive detectors for the International Space Station, intended to be used to measure the radiation dose uptake of materials during space flights.
"The strength of hackmanite's color depends on how much UV radiation it is exposed to, which means that the material can be used, for example, to determine the UV index of Sun's radiation. The hackmanite that will be tested on the space station will be used in a similar fashion, but this property can also be used in everyday applications. We have for example already developed a mobile phone application for measuring UV radiation that can be used by anyone," explains Sami Vuori.
The paper was published in June in the PNAS journal.
More information:Pauline Colinet et al, The structural origin of the efficient photochromism in natural minerals,Proceedings of the National Academy of Sciences(2022).DOI: 10.1073/pnas.2202487119
A fishy capture reveals a prized species moving south
by Southern Cross University
Credit: Dr. Benjamin Mos
A fishing expedition on the NSW Mid North Coast has hooked an unexpected catch for a Southern Cross University marine researcher.
When brothers Benjamin and Daniel Mos went fishing over summer, the pair did not anticipate their catch to be anything other than a photo opportunity or dinner. Instead the fish they captured and released, commonly called the barred javelin, spurred them to write a scientific paper now published in Journal of Fish Biology.
According to Dr. Benjamin Mos, a marine biologist based at Southern Cross University's National Marine Science Center, it was rare to find the barred javelin in New South Wales waters.
"While this species is likely well-known to fishers in Queensland, it is not something we typically find here. We had to look through a few fish books and websites to identify our specimens," Dr. Mos said.
"Our captures in late 2021 and early 2022 are the southern-most records for the barred javelin reported to date. And there may be more around the area.
"At the end of May 2022, we saw posts on social media about a barred javelin caught from Deep Creek, which is just north of the Nambucca River where we found our specimens."
The species has been previously sighted in the Richmond River and Clarence River systems on the NSW North Coast, which are around 200 kilometers north of the Nambucca River where the latest specimens were discovered.
It is not known if the arrival of the barred javelin this far south into NSW is due to changing ocean conditions.
"It is possible the sightings this far south are a one-off event. However, our sightings fit with a broader pattern occurring in the waters off south-eastern Australia which points towards a role of climate change," said Dr. Mos.
"In our region dozens of tropical species are moving southwards where oceans and estuaries are also warming faster than the global average."
According to Atlas of Living Australia records, the barred javelin has not been collected in NSW in more than 50 years.
The barred javelin's southernmost stronghold is Queensland's Moreton Bay, off Brisbane, where the species supports economically important recreational and commercial fisheries.
The species is a popular sport fish and reportedly good eating. The barred javelin grows to around 80cm in length and is found in estuaries and offshore to around 75 meters deep.
Dr. Mos said the newcomer was not of particular environmental concern at present. The barred javelin's relative rarity in NSW and generalist diet means it is unlikely to outcompete local species.
In the Mediterranean, tropical fishes moving into sub-tropical or temperate areas pose threats to biodiversity, public health, and fisheries. Two examples include herbivorous rabbitfishes chomping away at kelp forests, and poisonous silver-cheeked toadfish fouling fishers' nets and stealing their catch.
In contrast, the barred javelin may be welcomed by NSW recreational and commercial fishers.
"It is important that we understand where this species is showing up, and in what numbers," Dr. Mos said.
"If greater numbers make their way to NSW over coming decades the barred javelin may become a more common catch. It might then be necessary to look at whether specific size or catch limits are needed to ensure more fishers have the opportunity to catch this fish."
Because the barred javelin has been rarely captured in northern NSW, there are at present no specific catch or size limits for this species in NSW. A maximum daily bag limit of 20 applies to all fish in NSW that do not have specific bag and size limits. A 40 cm minimum length and bag limit of 10 applies in Queensland waters.
More information:Benjamin Mos et al, Range expansion of a widespread Indo‐Pacific haemulid, the barred javelin Pomadasys kaakan (Cuvier, 1830), in a climate change hotspot,Journal of Fish Biology(2022).DOI: 10.1111/jfb.15125
