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    ‘Fathom’ seeks to unravel humpback whales’ soulful songs

    In an opening scene of the new film Fathom, Michelle Fournet sits at her computer in the dark, headphones on. The marine ecologist at Cornell University is listening to a humpback whale song, her fingers bobbing like a conductor’s to each otherworldly croak and whine. Software converts crooning whale sounds into the visual space of craggy valleys and tall peaks, offering a glimpse at a language millions of years in the making.

    Debuting June 25 on Apple TV+, Fathom follows two scientific teams studying the enigmatic songs of humpbacks. The film captivates, diving into the quest to unveil the inner world of these animals and their ever-changing song culture — one considered far older than our ancestors’ first upright steps.

    On opposite sides of the Pacific Ocean, scientists head out onto the water. In a mountain-fringed bay in Alaska, Fournet makes repeated attempts to talk to the whales, playing them a painstakingly reconstructed rendition of a yelp that she thinks may be a greeting. In French Polynesia, behavioral ecologist Ellen Garland of the University of St. Andrews in Scotland listens to humpback songs, mapping how they are tweaked, learned and shared by whales across the South Pacific. These settings are stark and gorgeous, their isolation artfully shown through silent, foggy mornings and endless cobalt seas. In a film fundamentally about oceans filled with sound, ample quiet rests on the surface.

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    Directed by Drew Xanthopoulos, Fathom portrays humpbacks and other whales as complex, highly social beings without overstated anthropomorphism. In one goose bump–inducing scene, Garland’s narration identifies whales’ social similarities to humans, but set in a totally different environment. Perceiving each other chiefly with sound cast over stupefying distances, “whales evolved to build relationships in the dark,” Garland says.

    Fathom also gives an intimate look at what scientists undertake to find humpbacks in the vast ocean. Equipment breaks. Whales prove unpredictable. Strategies must change on the fly. These moments communicate the tough realities of science and the resilience needed for successful research.

    Much of the film is immersed in scenes like these, between troubleshooting and long waits on boat surveys. At times, the film’s pace languishes; connections to greater perspectives, such as the possibility of a globally interlinked song culture, are touched on but not fully examined.

    Nonetheless, Fournet’s simple distillation of her complex quest lingers: “I’m trying to start a conversation.” Her words remind us that Fathom is inherently seated at the threshold of unfathomable territory.

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    The teeth of ‘wandering meatloaf’ contain a rare mineral found only in rocks

    The hard, magnetic teeth of a leathery red-brown mollusk nicknamed “the wandering meatloaf” possess a rare mineral previously seen only in rocks. The mineral may help the mollusk — the giant Pacific chiton (Cryptochiton stelleri) — meld its soft flesh to the hard teeth it uses for grazing on rocky coastlines, researchers report online May 31 in Proceedings of the National Academy of Sciences.

    C. stelleri is the world’s largest chiton, reaching up to roughly 35 centimeters long. It is equipped with several dozen rows of teeth on a slender, flexible, tonguelike appendage called a radula that it uses to scrape algae off rocks. Those teeth are covered in magnetite, the hardest, stiffest known biomineral to date: It’s as much as three times as hard as human enamel and mollusk shells.

    C. stelleri uses its radula, a tonguelike structure (pictured) studded with hard magnetic teeth (dark objects), to graze on rocks. This composite image shows the radula’s stages of development, from earliest (left) to latest (right).Northwestern University

    Materials scientist Derk Joester and colleagues analyzed these teeth using high-energy X-rays from the Advanced Photon Source at Argonne National Laboratory in Lemont, Ill. They discovered that the interface between the teeth and flesh contained nanoparticles of santabarbaraite, an iron-loaded mineral never seen before in a living organism’s body.

    These nanoparticles help the underpinnings of the teeth vary in hardness and stiffness by at least a factor of two over distances of just several hundred micrometers — a few times the average width of a human hair. Such variations let these structures bridge the hard and soft parts of the mollusk’s body. Now that santabarbaraite has been found in one organism, the researchers suggest looking for it in insect cuticles and bacteria that sense magnetic fields.

    The teeth on C. stelleri’s tonguelike organ, seen in closeup in this scanning electron microscope image, help the mollusk scrape algae off of rocks.Northwestern University

    Using nanoparticles of a mineral similar to santabarbaraite, the scientists also 3-D printed strong, light materials with a range of hardness and stiffness. These composites might find use in soft robotics, including marrying soft and hard parts in bots that can squirm past obstacles that conventional robots cannot given their rigid parts, says Joester, of Northwestern University in Evanston, Ill. More

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    The U.S.’s first open-air genetically modified mosquitoes have taken flight

    The first genetically modified mosquitoes that will be allowed to fly free outdoors in the United States have started reaching the age for mating in the Florida Keys.

    In a test of the biotech company Oxitec’s GM male mosquitoes for pest control, these Aedes aegypti started growing from tiny eggs set out in toaster-sized, hexagonal boxes on suburban private properties in late April. On May 12, experiment monitors confirmed that males had matured enough to start flying off on their own to court American female mosquitoes.

    This short-term Florida experiment marks the first outdoor test in the United States of a strain of GM male mosquitoes as a highly targeted pest control strategy. This strain is engineered to shrink local populations of Ae. aegypti, a mosquito species that spreads dengue and Zika (SN: 7/29/16). That could start happening now that the GM mosquitoes have reached mating age because their genetics makes them such terrible choices as dads.

    The mosquitoes now waving distinctively masculine (extra fluffy) antennae in Florida carry genetic add-ons that block development in females. No female larvae should survive to adulthood in the wild, says molecular biologist Nathan Rose, Oxitec’s chief of regulatory affairs. Half the released males’ sons, however, will carry dad’s daughter-killing trait. The sons of the bad dads can go on to trick a new generation of females into unwise mating decisions and doomed daughters (SN: 1/8/09).

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    The trait is not designed to last in an area’s mosquitoes, though. The genetics just follow the same old rules of natural inheritance that mosquitoes and people follow: Traits pass to some offspring and not others. Only half a bad dad’s sons will carry the daughter-killing trait. The others will sire normal mosquito families.

    Imagined versions of live-mosquito pest control in Florida have been both glorified and savaged in spirited community meetings for some time (SN: 8/22/20). But now it’s real. “I’m sure you can understand why we’re so excited,” said Andrea Leal, executive director of the Florida Keys Mosquito Control District, at the mosquito test (virtual) kickoff April 29.

    The debate over these transgenic Ae. aegypti mosquitoes has gone on so long that Oxitec has upgraded its original more coddled version with one that is essentially plug and play. The newer strain, dubbed OX5034, no longer needs a breeding colony with its (biting) females and antibiotics in easy reach of the release area to produce fresh males.

    Instead, Oxitec can just ship eggs in a phase of suspended development from its home base in Abingdon, England, to whatever location around the world, high-tech or not, wants to deploy them. Brazil has already tested this OX5034 strain and gone through the regulatory process to permit Oxitec to sell it there.

    The targets for these potential living pest controls will be just their own kind. They represent only about 4 percent of the combined populations of the 45 or so mosquito species whining around the Keys. Other species get annoying, and a more recent invader, Ae. albopictus, can also spread dengue and Zika to some extent. Yet Leal blames just about all the current human disease spread by mosquitoes in the Keys, including last year’s dengue outbreak, on Ae. aegypti.

    It’s one of the top three mosquitoes in the world in the number of diseases it can spread, says Don Yee, an aquatic ecologist at the University of Southern Mississippi in Hattiesburg, who studies mosquitoes (SN: 3/31/21). His lab has linked at least three dozen human pathogens, including some viruses and worms, to Ae. aegypti. Although most mosquitoes lurk outdoors in vegetation, this one loves humankind. In the tropics, “the adults are literally resting on the walls or the ceiling,” he says. “They’re hanging around the bathroom.” The species bites humans for more than half of its blood meals.

    In a long-running battle with this beast, staff in Florida in late April added water to boxes of shipped eggs and set them out at selected suburban private properties on Vaca, Cudjoe and Ramrod Keys. Other spots, with no added mosquitoes, will be watched as controls. All locations were chosen in part because American-hatched females of the same species were already there to be wooed, Rose says.

    Toaster-sized hexagonal boxes (one pictured) that contain eggs of genetically modified Aedes aegypti were set out on selected private property in the Keys in late April. There the males develop normally — and then fly away to mate.Oxitec

    Males typically don’t billow out of their boxes in a gray cloud but emerge sporadically, a few at a time. If all goes well in this preliminary test, up to 12,000 GM mosquitoes in total across the release sites will take to the air each week for 12 weeks.

    Neighboring households will host mosquito traps to monitor how far from the nursery boxes the Oxitec GM males tend to fly. That’s data that the U.S. Environmental Protection Agency wants to see. Based on distance tests elsewhere, 50 meters might be the median, Rose estimates. 

    The distance matters because pest controllers want to keep the free-flying GM mosquitoes away from outdoor sources of the antibiotic tetracycline. That’s the substance the genetic engineers use as an off switch for the self-destruct mechanism in female larvae. Rearing facilities supply the antibiotic to larvae, turning off the lethal genetics and letting females survive in a lab to lay eggs for the next generation.

    If GM males loosed in Florida happened to breed with a female that lays eggs in some puddle of water laced with the right concentration of tetracycline, daughters that inherited the switch could survive to adulthood as biters and breeders. The main possible sources in the Keys would be sewage treatment plants, Rose says. The test designers say they have selected sites well away from them.

    After the distance tests, bigger releases still start looking at how well males fare and whether pest numbers shrink. Up to 20 million Oxitec mosquitoes in total could be released in tests running into the fall.

    Despite some high-profile protests, finding people to host the boxes was not hard, Rose says. “We were oversubscribed.” At public hearings, the critics of the project typically outshout the fans. Yet there’s also support. In a 2016 nonbinding referendum on using GM mosquitoes, 31 of 33 precincts in Monroe County, which comprises the Keys, voted yes for the test release. Twenty of those victories were competitive though, not reaching 60 percent.

    The males being released rely on a live-sons/dead-daughters strategy. That’s a change from the earlier strain of Oxitec mosquitoes. Those males sabotaged all offspring regardless of sex. The change came during the genetic redesign that permits an egg-shipping strategy. Surviving sons, however, mean the nonengineered genes in the new Oxitec strain can mix into the Florida population more than in the original version.

    Those mixed-in genes from the test are “unlikely” to strengthen Floridian mosquitoes’ powers to spread disease, researchers from the EPA and the U.S. Centers for Disease Control and Prevention wrote in a May 1, 2020 memorandum. Many factors besides mosquito genetics affect how a disease spreads, the reviewers noted. Oxitec will be monitoring for mixing.

    There may be at least one upside to mixing, Rose says. The lab colonies have little resistance to some common pesticides such as permethrin that the Floridian mosquitoes barely seem to notice.

    Pesticide resistance in the Keys is what drives a lot of the interest in GM techniques, says chemist Phil Goodman, who chairs the local mosquito control district’s board of commissioners. During the dengue outbreak in 2009 and 2010, the first one in decades, the district discovered that its spray program had just about zero effect on Ae. aegypti. With some rethinking of the program’s chemicals, the control district can now wipe out up to 50 percent of mosquitoes of this species in a treated area. That’s not great control, at best. Then when bad weather intervenes for days in a row, the mosquitoes rebound, Goodman says.

    The invasive mosquito species Aedes aegypti (shown), which can spread Zika, dengue and yellow fever, is now under attack in the Florida Keys by GM males genetically tweaked to sabotage the American mosquito populations.Joao Paulo Burini/Moment/Getty Images Plus

    Since that 2009–2010 outbreak, catching dengue in Florida instead of just through foreign travel has become more common. In 2020, an unusually bad year for dengue, Florida reported 70 cases caught locally, according to the CDC’s provisional tally. 

    Traditional pesticides can mess with creatures besides their pest targets, and some critics of the GMO mosquitoes also worry about unexpected ecological effects. Yet success of the Oxitec mosquitoes in slamming the current pests should not cause some disastrous shortage of food or pollination for natives, Yee says. Ae. aegypti invaded North America within the past four centuries, probably too short a time to become absolutely necessary for some native North American predator or plant.

    For more details on pretrial tests and data, the Mosquito Control District has now posted a swarm of documents about the GM mosquitoes. The EPA’s summary of Oxitec’s tests, for instance, reports no effects noticed for feeding the aquatic mosquito larvae to crawfish.

    Yee doesn’t worry much about either crustaceans or fish eating the larvae. “That’s somewhat analogous to saying, well, we’re concerned about releasing buffalo back into the prairies of the Midwest because they might get eaten by lions,” he says. Crawfish and fish, he notes, don’t naturally inhabit the small containers of still water where Ae. aegypti mosquitoes breed.

    Still, new mosquito-fighting options are springing up: Radiation techniques might become precise enough to sterilize males but leave them attractive enough to fool females into pointless mating. And researchers are developing other genetic ways to weaponize mosquitoes against their own kind.

    One technique that uses no GM wizardry just infects mosquitoes with Wolbachia bacteria that make biting unlikely to spread dengue. The latest data from Mexico and Columbia suggest this infection “could be effective in the southern U.S. and across the Caribbean,” says biologist Scott O’Neil, based in Ho Chi Minh City, Vietnam, founder of the World Mosquito Program.

    He has no plans for working in the United States but is instead focusing on places with much worse dengue problems. His version of the Wolbachia strategy just makes bites less dangerous (SN: 6/29/12). The mosquito population doesn’t shrink or grow less bloodthirsty, so this approach might not appeal to Floridians anyway. More

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    A common antibiotic slows a mysterious coral disease

    Slathering corals in a common antibiotic seems to temporarily soothe a mysterious tissue-eating disease, new research suggests.

    Just off Florida, a type of coral infected with stony coral tissue loss disease, or SCTLD, showed widespread improvement several months after being treated with amoxicillin, researchers report April 21 in Scientific Reports. While the deadly disease eventually reappeared, the results provide a spot of good news while scientists continue the search for what causes it.

    “The antibiotic treatments give the corals a break,” says Erin Shilling, a coral researcher at Florida Atlantic University’s Harbor Branch Oceanographic Institute in Fort Pierce. “It’s very good at halting the lesions it’s applied to.”

    Divers discovered SCTLD on reefs near Miami in 2014. Characterized by white lesions that rapidly eat away at coral tissue, the disease plagues nearly all of the Great Florida Reef, which spans 580 kilometers from St. Lucie Inlet in Marin County to Dry Tortugas National Park beyond the Florida Keys. In recent years, SCTLD has spread to reefs in the Caribbean (SN: 7/9/19).

    As scientists search for the cause, they are left to treat the lesions through trial and error. Two treatments that show promise involve divers applying a chlorinated epoxy or an amoxicillin paste to infected patches. “We wanted to experimentally assess these techniques to see if they’re as effective as people have been reporting anecdotally,” Shilling says.In April 2019, Shilling and colleagues identified 95 lesions on 32 colonies of great star coral (Montastraea cavernosa) off Florida’s east coast. The scientists dug trenches into the corals around the lesions to separate diseased tissue from healthy tissue, then filled the moats and covered the diseased patches with the antibiotic paste or chlorinated epoxy and monitored the corals over 11 months.

    Treatment with an amoxicillin paste (white bands, left) stopped a tissue-eating lesion from spreading over a great star coral colony up to 11 months later (right).E.N. Shilling, I.R. Combs and J.D. Voss/Scientific Reports 2021

    Within about three months of the treatment, some 95 percent of infected coral tissues treated with amoxicillin had healed. Meanwhile, only about 20 percent of infected tissue treated with chlorinated epoxy had healed in that time — no better than untreated lesions. 

    But a one-and-done treatment doesn’t stop new lesions from popping up over time, the team found. And some key questions remain unanswered, the scientists note, including how the treatment works on larger scales and what, if any, longer-term side effects the antibiotic could have on the corals and their surrounding environment.“Erin’s work is fabulous,” says Karen Neely, a marine biologist at Nova Southeastern University in Fort Lauderdale, Fla. Neely and her colleagues see similar results in their two-year experiment at the Florida National Marine Sanctuary. The researchers used the same amoxicillin paste and chlorinated epoxy treatments on more than 2,300 lesions on upwards of 1,600 coral colonies representing eight species, including great star coral.Those antibiotic treatments were more than 95 percent effective across all species, Neely says. And spot-treating new lesions that popped up after the initial treatment appeared to stop corals from becoming reinfected over time. That study is currently undergoing peer-review in Frontiers in Marine Science.

    “Overall, putting these corals in this treatment program saves them,” Neely says. “We don’t get happy endings very often, so that’s a nice one.” More

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    Discarded COVID-19 PPE such as masks can be deadly to wildlife

    A Magellanic penguin in Brazil ingested a face mask. A hedgehog in England got itself entangled in a glove. An octopus off the coast of France was found seeking refuge under a mask.

    Wildlife and ecosystems around the world are suffering from the impact of discarded single-use COVID-19 protective gear, researchers warn March 22 in Animal Biology. Latex gloves and polypropylene masks which protect people from the coronavirus are exacerbating the plastic pollution problem when not disposed of properly and are causing wildlife deaths (SN:11/20/20). The study is the first global documentation of the impacts of COVID-19 litter on wildlife via entanglement, entrapment and ingestion (SN:12/15/20).

    In August 2020, volunteers cleaning canals in Leiden, Netherlands, chanced upon a perch — a type of freshwater fish — trapped inside a finger of a latex glove. The ensnared fish was the first recorded wildlife casualty caused by COVID-19 litter in the Netherlands. The find shocked two Leiden-based biologists — Auke-Florian Hiemstra and Liselotte Rambonnet — who wanted to know more about the extent of COVID-19 litter’s impact on wildlife. They embarked on an extensive search, online and in newspapers, to collate examples.

    A perch found trapped in a latex glove (pictured) in a Leiden canal inspired two Dutch biologists to look into how discarded single-use PPE is impacting animals around the world.Auke-Florian Hiemstra

    They found 28 such instances from all around the world, pointing to a larger, global problem.   The earliest reported victim was from April 2020: an American robin in Canada, which appears to have died after getting entangled in a face mask. Pets are at risk, too: In Philadelphia, a domestic cat ingested a glove, and a pet dog in Boston that had consumed a face mask. “Animals with plastic in their stomach could starve to death,” says Rambonnet, of Leiden University.

    “What this paper does is give us insight to the extent of the [COVID-19] litter’s impact on wildlife, so we can make efforts to minimize the consequences,” says Anna Schwarz, a sustainable plastics researcher at TNO, an independent organization for applied scientific research in Utrecht, Netherlands. That could be a tall order: A report published by Hong Kong–based marine conservation organization OceansAsia, for instance, estimates that 1.56 billion face masks would have entered the world’s ocean last year, part of the 8 million to 12 million metric tons of plastic that reaches the oceans annually.

    As the far-reaching impacts of COVID-19 litter on wildlife become more apparent over time, Hiemstra, of the Naturalis Biodiversity Center, and Rambonnet are relying on citizen scientists to help them continue monitoring the situation: At, people from around the world can submit their observations of affected wildlife. To curb the growing hazards, the study authors recommend switching to reusables wherever possible, as well as cutting up disposal gloves and snipping the straps off of single-use masks to prevent animals from getting entangled or trapped in them.

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    “The paper highlights the importance of proper waste management, especially the recycling or disposal of single-use materials,” says Schwarz.

    But the situation isn’t always so dire. Some animals have commandeered discarded PPE for their own uses. COVID-19 litter has become so pervasive that birds have been observed using face masks and gloves as building materials for their nests. “Bird nests from 2020 are so easy to recognize,” says Hiemstra. More

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    Dazzling underwater photos capture new views and scientific detail of fish larvae

    The open ocean is a veritable soup of tiny critters, including newborn fishes. It’s hard to learn about them, though, because they are mere millimeters long and semitransparent. When netted from research vessels, their delicate body parts may get mashed or removed. Now, a partnership between scientists and scuba divers is giving researchers fresh perspectives on the secrets of larval fishes.

    Underwater photos taken at night — when larval fishes migrate to within 200 meters of the ocean surface — reveal colors, body structures and behaviors that could never be seen in preserved specimens. Examining those same fishes back in the lab lets ichthyologists match the photographed larval fishes to known species, researchers report March 30 in Ichthyology & Herpetology.

    Scientists at the Smithsonian Institution and the National Oceanic and Atmospheric Administration hatched a collaboration in 2016 with blackwater divers — who enter the ocean in the dark of night — to photograph larval fishes and collect them as specimens. With lights in hand, divers Jeff Milisen and Sarah Mayte snapped up-close photos of nearly 80 larval fishes, then gingerly captured and shipped them to scientists to be studied alongside their mugshots.

    “Fish larvae that looked utterly drab as specimens have turned out to have brilliantly colored markings and fantastic structures,” says Ai Nonaka, a larval fish expert at the Smithsonian’s National Museum of Natural History in Washington, D.C.

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    Fragile appendages

    Specialists like Nonaka sort out larval fish identities by looking at body shapes and minuscule features through microscopes and by analyzing DNA of larval tissue. Unlike their swimming parents, fish larvae drift on currents, and their strange body parts — adaptations for a drifting lifestyle — make larvae look nothing like adults. 

    “Larval fishes are extremely difficult to identify,” says Dave Johnson, an ichthyologist also at the Smithsonian. Scientists have mistakenly given larval fishes new scientific names, not recognizing them as early life stages of known species.

    Because larval fishes are soft and fragile, they don’t travel well. Larvae lose fins and other delicate structures that evoke their behavior. The scalloped ribbonfish (Zu cristatus) larva, for example, has spaghetti-like ornamental fins sprinkled with white spots that get broken off on specimens. The way these ornamental structures appear to flow out like tentacles in the images of wild larvae suggests the larvae could be jellyfish mimics, say the study authors.

    Scalloped ribbonfish (Zu cristatus) larva in the oceanJ. Milisen

    Scalloped ribbonfish (Z. cristatus) larva specimenA. Nonaka/Smithsonian NMNH

    The trailing guts of a barbeled dragonfish (Aristostomias sp.) larva get mashed or broken off altogether, but the undersea photo reveals it coiled up into a tight corkscrew. Nonaka and Johnson confess that scientists don’t yet understand the function of the trailing guts seen in some larval fishes. One theory is that exposed innards might somehow increase digestion efficiency, while another suggests they could confuse predators.

    Barbeled dragonfish (Aristostomias sp.) larva in the oceanJ. Milisen

    Barbeled dragonfish (Aristostomias sp.) larva specimenA. Nonaka/Smithsonian NMNH

    Hidden colors

    Ethanol preservation of specimens repels bacteria and fungi, but leaches out colors. The three-spot righteye flounder (Samariscus triocellatus) larva, bone white as a specimen, is bright blue. Its dorsal and anal fins are fringed with white, and rows of yellow spots dot the base of the fin rays. While their function has yet to be studied, it’s possible that these borders create a flickering visual effect to help the fish escape from predators, suggests Geoff Moser, a retired NOAA fisheries biologist not involved with the study. Called “flicker fusion,” it’s been examined in other animals such as striped snakes as a form of camouflage on the go.

    Three-spot righteye flounder (Samariscus triocellatus) larva in the oceanJ. Milisen

    Three-spot righteye flounder (S. triocellatus) larva specimenA. Nonaka/Smithsonian NMNH

    The deep-sea tripodfish (Bathymicrops sp.) is plain and pale when prepared as a specimen and uniform brown as an adult fish — not exactly a looker. But the larva appears to have donned a clown costume with large white and orange polka dots flecked on its otherwise blue-hued body. In an ethanol specimen, its pectoral fins look soft and ghostly, whereas the living larva sports flamboyant, spiky and spotted fins. The function of the coloration is unknown. says Nonaka, but it could also be a flicker fusion trick.

    Deep-sea tripodfish (Bathymicrops sp.) larva in the oceanJ. Milisen

    Deep-sea tripodfish (Bathymicrops sp.) larva specimenA. Nonaka/Smithsonian NMNH

    Fishy behavior

    In larval specimens, scientists can observe some structures as evidence of behaviors. But undersea observations of wild larval fishes can show what they’re really up to when they are alive. The larva of the barred conger (Ariosoma fasciatum) is super flat, quite unlike the cylindrical adult. Yet a photo shows that it swims like an adult barred conger, by undulating its long body laterally. So, while it’s more svelte as a larva, it’s got some of the adult movements down.

    Barred conger (Ariosoma fasciatum) larva in the oceanJ. Milisen

    Barred conger (A. fasciatum) larva specimenA. Nonaka/Smithsonian NMNH

    Undersea observations can also reveal associations larvae have with other marine animals, including other tiny critters that also ride the currents. For example, a petite Pacific pomfret (Brama japonica) larva was caught on camera riding on a jellyfish. That’s a discovery that the study authors were unwilling to even speculate about. Although larval fishes have been seen taking shelter in the tentacles of jellies, hitching a ride on top of a jellyfish seems like an odd twist on that behavior.

    A pacific pomfret (Brama japonica) larva (pictured from three angles) in the ocean, riding a jellyfishJ. Milisen (photos); E. Otwell/Science News (collage)

    Pacific pomfret (Brama japonica) larva specimenA. Nonaka/Smithsonian NMNH

    Each larval fish that gets identified by scientists sets the stage for conservation. By knowing where larval fishes of particular species live, researchers can better advise on how to manage the ocean ecosystems the fishes depend on for survival.

    Conservation planning also requires knowledge of behavior (SN: 12/30/10). So photographing larval fishes and making their specimens available for identification means researchers get a handle on fishes’ behavioral adaptations for survival in the wild.

    “I’ve been working with fish larvae for over 40 years,” says Moser. “The chance to see these larvae in their environment was a wonderful advance in our scientific endeavors.” More

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    A year after Australia’s wildfires, extinction threatens hundreds of species

    When Isabel Hyman heads out in coming weeks to the wilds of northern New South Wales, she’s worried about what she won’t find. Fifteen years ago, the malacologist — or mollusk scientist — with the Australian Museum made an incredible discovery among the limestone outcrops there: a tiny, 3-millimeter-long snail, with a ribbed, dark golden-brown shell, that was new to science.
    Subsequently named after her husband, Hugh Palethorpe, Palethorpe’s pinwheel snail (Rophodon palethorpei) “is only known from a single location, at the Kunderang Brook limestone outcrops in Werrikimbe National Park,” she says. Now it may become known for a different, more devastating distinction: It is one of hundreds of species that experts fear have been pushed close to, or right over, the precipice of extinction by the wildfires that blazed across more than 10 million hectares of southeastern Australia in the summer of 2019–2020.
    “This location was completely burnt,” says Hyman, who is based in Sydney. “We expect the mortality at this site could be very high and … there is a possibility this species is extinct.”
    A year after the last of the fires were doused, their toll on species is becoming increasingly clear.  Flames devoured more than 20 percent of Australia’s entire forest cover, according to a February 2020 analysis in Nature Climate Change. Even if plants and animals survived the flames, their habitats may have been so changed that their survival is at risk (SN: 2/11/20). As a result of the scale of the disaster, experts say that more than 500 species of plants and animals may now be endangered — or even completely gone. 
    A wallaby licks its burnt paws after escaping a bushfire near Nana Glen in New South Wales on November 12, 2019.Wolter Peeters/The Sydney Morning Herald via Getty Image
    Australia’s iconic koala became the poster child of the crisis as images of rescuers carrying these singed marsupials out of the flames went global: As many as 60,000 of the nation’s estimated population of 330,000 koalas perished in the fires, ecologists concluded in December in a report for World Wildlife Fund Australia. While there’s no doubt that such charismatic megafauna suffered enormously, the greatest toll is likely to have been in other groups of species, such as invertebrates and plants, which often escape the public’s attention.
    As Kingsley Dixon, an ecologist at Curtin University in Perth told the Associated Press last year: “I don’t think we’ve seen a single event in Australia that has destroyed so much habitat and pushed so many creatures to the very brink of extinction.”

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    Koala charisma
    Even before the fires, many vertebrate species were already on downward trends, says John Woinarski, an ecologist at Charles Darwin University in Darwin. The blazes have “exacerbated the threats that were driving the declines,” he says.
    For example, fluffy arboreal marsupials called greater gliders (Petauroides volans) had already experienced a 50 percent population decline in recent decades. The fires then burned a third of their remaining habitat along Australia’s eastern coastline. An ongoing assessment may lead to the gliders being recategorized from vulnerable to endangered.
    Overall, 49 vertebrates that previously were not endangered now qualify for being listed as threatened under Australia’s guidelines for that designation, researchers reported in July in Nature Ecology and Evolution. That shift alone would increase the tally of nationally protected nonmarine vertebrate species by about 15 percent, from 324 to 373.
    Another 21 already threatened vertebrates had more than 30 percent of their ranges burned, and some may now qualify for being reassessed to higher categories of threat, the authors found. One species that may need to be recategorized is the koala (Phascolarctos cinereas), with some state’s populations that were hardest hit under consideration to be upgraded from vulnerable to endangered. 
    A koala named Paul recovers from his burns at an ICU in November 2019 after being rescued by volunteers following weeks of bushfires across New South Wales and Queensland.Edwards/Getty Image
    Besides the impact on koalas, the WWF Australia report suggests that as many as 3 billion individual mammals, birds, reptiles and frogs died or were displaced during the crisis. Though those figures are astounding, the impacts on lesser-studied groups such as invertebrates and plants may have been even greater.
    “Many of those have much smaller ranges [than vertebrates], which means they are going to be even more impacted when a big fire goes through,” says James Watson, a conservation scientist at the University of Queensland in Brisbane and an author of the Nature Ecology and Evolution paper on vertebrates. “I am willing to bet that there’s many species … that may disappear forever.”
    Invertebrate impact
    In February, more than 100 biologists convened the first of several online workshops to assess whether 234 Australian invertebrates now need to be added to the International Union for the Conservation of Nature’s Red List — a global who’s who of threatened species. 
    Snails, similar to many invertebrates, are particularly susceptible to wildfires, as they are unable to outrun flames and can’t survive intense heat, Hyman notes. Many also have small ranges that were completely incinerated, leaving no survivors that can recolonize the burned area.
    “A snail can’t do much to escape,” she says. “You could expect more than 90 percent mortality in a high-intensity bushfire.” In October, Hyman’s team published one of the first papers quantifying the impacts on invertebrates in New South Wales in the Technical Reports of the Australian Museum Online.
    The Palethorpe’s pinwheel snail (Rophodon palethorpei) has not yet turned up in searches following the wildfires, but other snail species did survive.Vince Railton, Queensland Museum
    Their surveys showed that 29 species in the state — including dung beetles, freshwater crayfish, flies, snails and spiders — had their entire ranges burned. Another 46 species had at least half their known habitat within the fire zones. These 75 species were among the 234 under consideration for adding to the IUCN Red List during the biologists’ first online workshop.
    “We’ve gathered together 230-odd species that are believed to now be of concern. These include a range of different taxa from land snails to millipedes to arachnids to insects, and this 230 is growing rapidly,” says Jess Marsh, an arachnologist at Charles Darwin University who was one of the conveners of the workshop. “I expect it will massively increase.”
    Some of the spiders she studies were the first to be added to that list. She’s already spent several months on South Australia’s Kangaroo Island hunting without luck for the Kangaroo Island assassin spider (Zephyrarchaea austini). Dependent on leaf litter suspended in the understory, and restricted to just a few locations that were razed in early 2020, she suspects that the species may be extinct.
    Spiders on Kangaroo Island such as this assassin spider (Zephyrarchaea austini) may now be extinct after most of their habitat was razed in early 2020.M.G. Rix and M.S. Harvey/ZooKeys 2012
    “There’s no understory vegetation left, let alone any leaf litter suspended in it, so that species is really hanging in the balance,” says Marsh.
    Generally, the species being considered for recognition as endangered had more than 50 percent of their ranges burned, lived in flammable parts of the habitat and have little ability to disperse to other areas. More than 150 of the 234 species being urgently assessed had their entire range burned. And it’s not just the flames themselves that are problematic; so is the reshaped environment following fires. Millipedes, for example, are very vulnerable not only to fire but also to drying out in the reduced shade and shelter of the post-fire environment.
    “A lot of invertebrates are very susceptible to desiccation, and need cover and humidity to survive a hot summer, which are obviously lacking following the fire,” Marsh says. “Taking into account all of the threats … we could be looking at significant numbers going extinct.”
    Rooted in place
    Lost vegetation hasn’t just put animals in danger. Many plants themselves may also be at risk, though experts have yet to compile an official list.
    Rachael Gallagher, a plant ecologist at Macquarie University in Sydney, has been prioritizing endemic plant species — those found nowhere else on Earth — that are in most urgent need of conservation for the Australian government. Perhaps surprisingly, she’s particularly worried about some trees that actually depend on fire to survive. Eucalypts known as alpine ash (Eucalyptus delegatensis) and mountain ash (E. regnans), for instance, are typically killed by fire and then regenerate from surviving seeds in the aftermath. Australia has many trees that must complete their entire life cycle from germination through to reproductively mature adult before the next major bushfire passes through (SN: 2/11/20). For some species, this may take 15 to 20 years.
    Some trees in Australia, such as this mountain ash (Eucalyptus regnans), depend on fire for their lifecycle, but recent wildfires may have been too much too soon.station96/iStock/Getty Images Plus
    The problem now is that climate change has increased the frequency of fires to the degree that many of these plants are unable to reach adulthood and set seed before the next fire passes through, meaning they may be lost from these ecosystems (SN: 3/4/20).
    The fires burned 25–100 percent of the ranges of 257 species of plants for which “the historical intervals between fire events across their range are likely to be too short to allow them to effectively regenerate,” Gallagher says. These species, which have some degree of fire tolerance, are at “increased risk of extinction.” These include shrubs and trees such as the granite boronia (Boronia granitica), Forrester’s bottlebrush (Callistemon forresterae), dwarf cypress pine (Callitris oblonga) and the Wolgan snow gum (Eucalyptus gregsoniana).
    Found, not lost
    Nevertheless, as researchers head out into the field to assess what’s lost, what they are sometimes finding are glimmers of hope. “Australian plants are remarkably resilient and there’s been regeneration in places where nobody thought there would be,” Gallagher says.
    One species that survived against all the odds is the Gibraltar Range waratah (Telopea aspera), a drought-resistant shrub with leathery leaves and bright red flowers. “This species has a very small range, being specialized to granite outcrops in one mountain range, which was burnt during the fires,” she says. “However, it has been noted as resprouting after the fires by park rangers and, in the absence of another fire in coming years, is likely to be able to recover.”
    Several animal species that were thought to be in grave peril following the fires that burned nearly half of the 4,400-square-kilometer Kangaroo Island have survived better than expected too (SN: 1/13/20). In the particularly badly burned reserves of the western end of the island, tiny marsupial carnivores called Kangaroo Island dunnarts (Sminthopsis aitkeni) are frequently appearing on camera traps. Swiftly erected predator-exclusion fences now protect survivors from feral cats.
    Tiny marsupials known as Kangaroo Island dunnarts (Sminthopsis aitkeni) have fared much better than other animals, appearing frequently on camera traps.Australian Wildlife Conservancy
    Similarly, large flocks of the glossy black-cockatoo (Calyptorhynchus lathami) have adapted by moving to unburned areas with food trees, says Karleah Berris of Natural Resources Kangaroo Island, who heads the crew that manages the endangered birds. Better news yet, a surprising number of birds bred and fledged young in mid-2020. “The important thing now is to protect what is left from fire until the burnt areas regenerate,” she says. “But I think, at present, all signs are that they are coping.”
    Hyman says that, hearteningly, her team found handfuls of survivors of some snail species during several surveys in New South Wales in late 2020. The snails turned up in small patches of unburned habitat, sometimes at the bottom of gullies or in deep leaf litter around the bases of large trees. And that gives her hope that other snail species may have held on in other, larger unburned patches with greater numbers of survivors.
    “But the question then becomes, what sort of recovery can they make from that?” she says. “Whether they can recover and breed up and start to move back into surviving areas again perhaps depends on how dry the weather is in coming years and if there are more fires.”
    She’s still hoping that a handful of Palethorpe’s pinwheel snails may have clung on against all the odds. “My husband is on tenterhooks wondering if his snail is still there or not,” she says. More

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    Some bacteria are suffocating sea stars, turning the animals to goo

    The mysterious culprit behind a deadly sea star disease is not an infection, as scientists once thought.
    Instead, multiple types of bacteria living within millimeters of sea stars’ skin deplete oxygen from the water and effectively suffocate the animals, researchers report January 6 in Frontiers in Microbiology. Such microbes thrive when there are high levels of organic matter in warm water and create a low oxygen environment that can make sea stars melt in a puddle of slime.
    Sea star wasting disease — which causes lethal symptoms like decaying tissue and loss of limbs — first gained notoriety in 2013 when sea stars living off the U.S. Pacific Coast died in massive numbers. Outbreaks of the disease had also occurred before 2013, but never at such a large scale.
    Scientists suspected that a virus or bacterium might be making sea stars sick. That hypothesis was supported in a 2014 study that found unhealthy animals may have been infected by a virus (SN: 11/19/14). But the link vanished when subsequent studies found no relationship between the virus and dying sea stars, leaving researchers perplexed (SN: 5/5/16). 

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    The new finding that a boom of nutrient-loving bacteria can drain oxygen from the water and cause wasting disease “challenges us to think that there might not always be a single pathogen or a smoking gun,” says Melissa Pespeni, a biologist at the University of Vermont in Burlington who was not involved in the work. Such a complex environmental scenario for killing sea stars “is a new kind of idea for [disease] transmission.”  
    There were certainly many red herrings during the hunt for why sea stars along North America’s Pacific Coast were melting into goo, says Ian Hewson, a marine biologist at Cornell University. In addition to the original hypothesis of a viral cause for sea star wasting disease — which Hewson’s team reported in 2014 in Proceedings of the National Academy of Sciences but later disproved — he and colleagues analyzed a range of other explanations, from differences in water temperature to exposing the animals to bacteria. But nothing reliably triggered wasting.   
    Then the researchers examined the types of bacteria living with healthy sea stars compared with those living among the animals with wasting disease. “That was when we had our aha moment,” says Hewson.
    Not all sea stars are susceptible to sea star wasting disease. Species that have more structures on their surface, and therefore more surface area for bacteria to deplete oxygen, appear more likely to get severely sick compared with flatter sea stars. In this photo, an ochre sea star (Pisaster ochraceus) succumbs to the disease in Davenport, Calif., in June 2018.Ian Hewson
    Types of bacteria known as copiotrophs, which thrive in environments with lots of nutrients, were present around the sea stars at higher levels than normal either shortly before the animals developed lesions or as they did so, Hewson and colleagues found. Bacterial species that survive only in environments with little to no oxygen were also thriving. In the lab, the sea stars began wasting when the researchers added phytoplankton or a common bacterial-growth ingredient to the warm water tubs those microbes and sea stars were living in.  
    Experimentally depleting oxygen from the water had a similar effect, causing lesions in 75 percent of the animals, while none succumbed in the control group. Sea stars breathe by diffusing oxygen over small external projections called skin gills, so the lack of oxygen in the wake of flourishing copiotrophs leaves sea stars struggling for air, the data show. It’s unclear how the animals degrade in low oxygen conditions, but it could be due to massive cell death.
    Although the disease isn’t caused by a contagious pathogen, it is transmissible in the sense that dying sea stars generate more organic matter that spur bacteria to grow on healthy animals nearby. “It’s a bit of a snowball effect,” Hewson says.
    The team also analyzed tissues from sea stars that had succumbed in the 2013 mass die-off — which followed a large algal bloom on the U.S. West Coast — to see if such environmental conditions might explain that outbreak. In fast-growing appendages that help them move, the sea stars that perished had high amounts of a form of nitrogen found in low oxygen conditions — a sign that those animals may have died from a lack of oxygen.
    The problem may get worse with climate change, Hewson says. “Warmer waters can’t have as much oxygen [compared with colder water] just by physics alone.” Bacteria, including copiotrophs, also flourish in warm water.  
    But pinpointing the likely cause could help experts better treat sick sea stars in the lab, Hewson says. Some techniques include increasing the oxygen levels in a water tank to make the gas more easily available to sea stars or getting rid of extra organic matter with ultraviolet light or water exchange.
    “There’s still a lot to figure out with this disease, but I think [this new study] gets us a long way to understanding how it comes about,” Pespeni says. More