Estimating somatic growth of fishes from maximum age or maturity

Two new data-limited methods to estimate somatic growth, applicable to species with indeterminate growth such as fishes or invertebrates.

Somatic growth rate is a central life-history parameter, especially in species like fishes or invertebrates which grow throughout their lives. It is needed in conservation and fisheries management but it can sometimes be tricky to estimate.

In a recent study published in the journal Acta Ichthyologica et Piscatoria, Dr. Rainer Froese of the Helmholtz Centre for Ocean Research proposes new simplified methods for somatic growth estimation.

A school of Jacks pass overhead at Viuda (Widow) dive site, in Coiba National Park, Panama, a UNESCO World Heritage site. Photo by LASZLO ILYES under a CC-BY 2.0 license.

Dr. Froese presents two new data-limited methods to estimate somatic growth from maximum length combined with either length or age at maturation or with maximum age. They are applicable to a wide range of species, sizes, and habitats. Using these new methods, growth parameter estimates were produced for the first time for 110 fish species.

“The growth estimates derived with the new methods presented in this study appear suitable for consideration and preliminary guidance in applications for conservation or management,” Dr. Froese points out in his study.

He goes on to suggest that journals accept growth estimates performed with the new methods as new knowledge, if they are the first for a given species.

In order to facilitate the conservation and management of natural resources, FishBase will continue to compile growth parameters, including results obtained with these new methods.

Research article:

Froese R (2022) Estimating somatic growth of fishes from maximum age or maturity. Acta Ichthyologica et Piscatoria 52(2): 125-133. https://doi.org/10.3897/aiep.52.80093

First-ever fish species described by a Maldivian scientist

Though there are hundreds of species of fish found off the coast of the Maldives, a mesmerizing new addition is the first-ever to be formally described by a Maldivian researcher.

Named after the country’s national flower, the species is added to the tree of life as part of the California Academy of Sciences’ global Hope for Reefs initiative

Originally published by the California Academy of Sciences

Though there are hundreds of species of fish found off the coast of the Maldives, a mesmerizing new addition is the first-ever to be formally described—the scientific process an organism goes through to be recognized as a new species—by a Maldivian researcher.

The new-to-science Rose-Veiled Fairy Wrasse (Cirrhilabrus finifenmaa), described in the journal ZooKeys, is also one of the first species to have its name derived from the local Dhivehi language, ‘finifenmaa’ meaning ‘rose’, a nod to both its pink hues and the island nation’s national flower.

Scientists from the California Academy of Sciences, the University of Sydney, the Maldives Marine Research Institute (MMRI), and the Field Museum collaborated on the discovery as part of the Academy’s Hope for Reefs initiative aimed at better understanding and protecting coral reefs around the world.

“It has always been foreign scientists who have described species found in the Maldives, even those that are endemic, without much involvement from local scientists. This time, it is different and getting to be part of something for the first time has been really exciting, especially having the opportunity to work alongside top ichthyologists on such an elegant and beautiful species,”

says study co-author and Maldives Marine Research Institute biologist Ahmed Najeeb.

First collected by researchers in the 1990s, C. finifenmaa was originally thought to be the adult version of a different species, Cirrhilabrus rubrisquamis, which had been described based on a single juvenile specimen from the Chagos Archipelago, an island chain 1,000 kilometers (621 miles) south of the Maldives. 

In this new study, however, the researchers took a more detailed look at both adults and juveniles of the multicolored marvel, measuring and counting various features, such as the color of adult males, the height of each spine supporting the fin on the fish’s back and the number of scales found on various body regions. These data, along with genetic analyses, were then compared to the C. rubrisquamis specimen to confirm that C. finifenmaa is indeed a unique species. 

Importantly, this revelation greatly reduces the known range of each wrasse, a crucial consideration when setting conservation priorities.  

“What we previously thought was one widespread species of fish, is actually two different species, each with a potentially much more restricted distribution. This exemplifies why describing new species, and taxonomy in general, is important for conservation and biodiversity management,”

says lead author and University of Sydney doctoral student Yi-Kai Tea. 

Despite only just being described, the researchers say that the Rose-Veiled Fairy Wrasse is already being exploited through the aquarium hobbyist trade. 

“Though the species is quite abundant and therefore not currently at a high risk of overexploitation, it’s still unsettling when a fish is already being commercialized before it even has a scientific name. It speaks to how much biodiversity there is still left to be described from coral reef ecosystems,”

says senior author and Academy Curator of Ichthyology Luiz Rocha, PhD, who co-directs the Hope for Reefs initiative.

Last month, Hope for Reefs researchers continued their collaboration with the MMRI by conducting the first surveys of the Maldives’ ‘twilight zone’ reefs—the virtually unexplored coral ecosystems found between 50- to 150-meters (160- to 500-feet) beneath the ocean’s surface—where they found new records of C. finifenmaa along with at least eight potentially new-to-science species yet to be described. 

This new-to-science Rose-Veiled Fairy Wrasse (Cirrhilabrus finifenmaa) became the first Maldivian fish to ever be described by a local researcher.
Photo by Yi-Kai Tea.

For the researchers, this kind of international partnership is pivotal to best understand and ensure a regenerative future for the Maldives’ coral reefs. 

“Nobody knows these waters better than the Maldivian people. Our research is stronger when it’s done in collaboration with local researchers and divers. I’m excited to continue our relationship with MMRI and the Ministry of Fisheries to learn about and protect the island nation’s reefs together,”

says Rocha says

“Collaborating with organizations such as the Academy helps us build our local capacity to expand knowledge in this field. This is just the start and we are already working together on future projects. Our partnership will help us better understand the unexplored depths of our marine ecosystems and their inhabitants. The more we understand and the more compelling scientific evidence we can gather, the better we can protect them,”

adds Najeeb.

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Research article:

Tea Y-K, Najeeb A, Rowlett J, Rocha LA (2022) Cirrhilabrus finifenmaa (Teleostei, Labridae), a new species of fairy wrasse from the Maldives, with comments on the taxonomic identity of C. rubrisquamis and C. wakanda. ZooKeys 1088: 65-80. https://doi.org/10.3897/zookeys.1088.78139

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Scientists took a rare chance to prove we can quantify biodiversity by ‘testing the water’

Recent study conducted at a UK fishery farm provides new evidence that DNA from water samples can accurately determine fish abundance and biomass

Organisms excrete DNA in their surroundings through metabolic waste, sloughed skin cells or gametes, and this genetic material is referred to as environmental DNA (eDNA).

As eDNA can be collected directly from water, soil or air, and analysed using molecular tools with no need to capture the organisms themselves, this genetic information can be used to report biodiversity in bulk. For instance, the presence of many fish species can be identified simultaneously by sampling and sequencing eDNA from water, while avoiding harmful capture methods, such as netting, trapping or electrofishing, currently used for fish monitoring.

While the eDNA approach has already been applied in a number of studies concerning fish diversity in different types of aquatic habitats: rivers, lakes and marine systems, its efficiency in quantifying species abundance (number of individuals per species) is yet to be determined. Even though previous studies, conducted in controlled aquatic systems, such as aquaria, experimental tanks and artificial ponds, have reported positive correlation between the DNA quantity found in the water and the species abundance, it remains unclear how the results would fare in natural environments.

However, a research team from the University of Hull together with the Environment Agency (United Kingdom), took the rare opportunity to use an invasive species eradication programme carried out in a UK fishery farm as the ultimate case study to evaluate the success rate of eDNA sampling in identifying species abundance in natural aquatic habitats. Their findings were published in the open-access, peer-reviewed journal Metabarcoding and Metagenomics.

“Investigating the quantitative power of eDNA in natural aquatic habitats is difficult, as there is no way to ascertain the real species abundance and biomass (weight) in aquatic systems, unless catching all target organisms out of water and counting/measuring them all,”

explains Cristina Di Muri, PhD student at the University of Hull.
Drained pond after fish translocation.
Photo by Dr. Watson H.V.

During the eradication, the original fish ponds were drained and all fish, except the problematic invasive species: the topmouth gudgeon, were placed in a new pond, while the original ponds were treated with a piscicide to remove the invasive fish. After the eradication, the fish were returned to their original ponds. In the meantime, all individuals were counted, identified and weighed from experts, allowing for the precise estimation of fish abundance and biomass.

“We then carried out our water sampling and ran genetic analysis to assess the diversity and abundance of fish genetic sequences, and compared the results with the manually collected data. We found strong positive correlations between the amount of fish eDNA and the actual fish species biomass and abundance, demonstrating the existence of a strong association between the amount of fish DNA sequences in water and the actual fish abundance in natural aquatic environments,”

reports Di Muri.
Environmental DNA sampling using water collection bottles
Photo by Dr. Peirson G.

The scientists successfully identified all fish species in the ponds: from the most abundant (i.e. 293 carps of 852 kg total weight) to the least abundant ones (i.e. one chub of 0.7 kg), indicating the high accuracy of the non-invasive approach.

“Furthermore, we used different methods of eDNA capture and eDNA storage, and found that results of the genetic analysis were comparable across different eDNA approaches. This consistency allows for a certain flexibility of eDNA protocols, which is fundamental to maintain results comparable across studies and, at the same time, choose the most suitable strategy, based on location surveyed or resources available,”

elaborates Di Muri.

“The opportunity of using eDNA analysis to accurately assess species diversity and abundance in natural environments will drive a step change in future species monitoring programmes, as this non-invasive, flexible tool is adaptable to all aquatic environments and it allows quantitative biodiversity surveillance without hampering the organisms’ welfare.”

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Original publication:

Di Muri C, Lawson Handley L, Bean CW, Li J, Peirson G, Sellers GS, Walsh K, Watson HV, Winfield IJ, Hänfling B (2020) Read counts from environmental DNA (eDNA) metabarcoding reflect fish abundance and biomass in drained ponds. Metabarcoding and Metagenomics 4: e56959. https://doi.org/10.3897/mbmg.4.56959

Wakanda Forever! Scientific divers describe new purple species of “twilight zone” fish from Africa

Named for Black Panther’s mythical nation of Wakanda, a dazzling new “Vibranium” Fairy Wrasse enchants with purple scales and a preference for deep, little-known mesophotic reefs up to 260 feet below the surface

Africa has new purple-clad warriors more than 200 feet beneath the ocean’s surface. Deep-diving scientists from the California Academy of SciencesHope for Reefs initiative and the University of Sydney spotted dazzling fairy wrasses—previously unknown to science—in the dimly lit mesophotic coral reefs of eastern Zanzibar, off the coast of Tanzania. 

Preserved specimen of Vibranium fairy wrasse (Cirrhilabrus wakanda) retains its striking coloration.
Photo by Jon Fong © 2018 California Academy of Sciences.

The multicolored wrasses sport deep purple scales so pigmented, they even retain their color (which is typically lost) when preserved for research. The scientists name this “twilight zone” reef-dweller Cirrhilabrus wakanda (common name “Vibranium Fairy Wrasse”) in honor of the mythical nation of Wakanda from the Marvel Entertainment comics and movie Black Panther. The new fish is described in the open-access journal Zookeys.

Female specimen of Vibranium fairy wrasse (Cirrhilabrus wakanda) in its natural habitat (Zanzibar). Photo by Luiz Rocha © 2018 California Academy of Sciences.

Yi-Kai Tea, lead author and ichthyology PhD student from the University of Sydney, says:

“When we thought about the secretive and isolated nature of these unexplored African reefs, we knew we had to name this new species after Wakanda. We’ve known about other related fairy wrasses from the Indian Ocean, but always thought there was a missing species along the continent’s eastern edge. When I saw this amazing purple fish, I knew instantly we were dealing with the missing piece of the puzzle.”

The Academy scientists say Cirrhilabrus wakanda’s remote home in mesophotic coral reefs—below recreational diving limits—probably contributed to their long-hidden status in the shadows of the Indian Ocean. 

A California Academy diver on an expedition in the Indian Ocean.
Photo by Bart Shepherd © 2018 California Academy of Sciences.

Therefore, Hope for Reefs’ scientific divers are highly trained for the dangerous process of researching in these deep, little-known mesophotic reefs, located 200 to 500 feet beneath the ocean’s surface. Accessing them requires technical equipment and physically intense training well beyond that of shallow-water diving. The team’s special diving gear (known as closed-circuit rebreathers) includes multiple tanks with custom gas blends and electronic monitoring equipment that allow the divers to explore deep reefs for mere minutes before a lengthy, hours-long ascent to the surface.

Dr. Luiz Rocha, Academy Curator of Fishes and co-leader of the Hope for Reefs, comments:

“Preparation for these deep dives is very intense and our dive gear often weighs more than us. When we reach these reefs and find unknown species as spectacular as this fairy wrasse, it feels like our hard work is paying off.”

California Academy’s “twilight zone” dive gear prepped for Zanzibar.
Photo by Luiz Rocha © 2018 California Academy of Sciences.

Using a microscope, the team examined the specimens’ scales, fin rays, and body structures. DNA and morphological analyses revealed the new fairy wrasse to be different from the other seven species in the western Indian Ocean as well as other relatives in the Pacific. The new species’ common name is inspired by the fictional metal vibranium, a rare, and, according to Rocha, “totally awesome” substance found in the nation of Wakanda. The Vibranium Fairy Wrasse’s purple chain-link scale pattern reminded the scientists of Black Panther’s super-strong suit and the fabric motifs worn by Wakandans in the hit film.

Precious life in deep reefs

In a recent landmark paper, the Academy team found that twilight zone reefs are unique ecosystems bursting with life and are just as vulnerable to human threats as their shallow counterparts. Their findings upended the long-standing assumption that species might avoid human-related stressors on those deeper reefs. The Hope for Reefs team will continue to visit and study twilight zone sites around the world to shed light on these often-overlooked ecosystems.

Newly described Pohnpei fish (Liopropoma incandescens). Photo by Luiz Rocha © 2018 California Academy of Sciences.

In addition to this new fish from Zanzibar, Rocha and his colleagues recently published descriptions of mesophotic fish from Rapa Nui (Easter Island) and Micronesia. Luzonichthys kiomeamea is an orange, white, and sunny yellow dwarf anthias endemic to Rapa Nui, and the basslet Liopropoma incandescens (another new species published today in Zookeys) inhabits Pohnpei’s deep reefs—a neon orange and yellow specimen collected from a rocky slope 426 feet beneath the ocean’s surface.  

“It’s a time of global crisis for coral reefs, and exploring little-known habitats and the life they support is now more important than ever,” concludes Rocha. “Because they are out of sight, these deeper reefs are often left out of marine reserves, so we hope our discoveries inspire their protection.”

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(Text by the California Academy of Sciences, USA)

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Research articles:

Tea YK, Pinheiro HT, Shepherd B, Rocha LA (2019) Cirrhilabrus wakanda, a new species of fairy wrasse from mesophotic ecosystems of Zanzibar, Tanzania, Africa (Teleostei, Labridae). ZooKeys 863: 85–96. https://doi.org/10.3897/zookeys.863.35580.

Pinheiro HT, Shepherd B, Greene BD, Rocha LA (2019) Liopropoma incandescens sp. nov. (Epinephelidae, Liopropominae), a new species of basslet from mesophotic coral ecosystems of Pohnpei, Micronesia. ZooKeys 863: 97–106. https://doi.org/10.3897/zookeys.863.33778.

New species of fish parasite named after Xena, the warrior princess

A study of parasitic crustaceans attaching themselves inside the branchial cavities (the gills) of their fish hosts was recently conducted in order to reveal potentially unrecognised diversity of the genus Elthusa in South Africa.

While there had only been one species known from the country, a new article published in the open-access journal ZooKeys adds another three to the list.

For one of them, the research team from North-West University (South Africa): Serita van der Wal, Prof Nico Smit and Dr Kerry Hadfield, chose the name of the fictional character Xena, the warrior princess. The reason was that the females appeared particularly tough with their characteristic elongated and ovoid bodies. Additionally, the holotype (the first specimen used for the identification and description of the previously unknown species) is an egg-carrying female.

Formally recognised as Elthusa xena, this new to science species is so far only known from the mouth of the Orange River, Alexander Bay, South Africa (Atlantic Ocean). It is also the only Elthusa species known to parasitise the intertidal Super klipfish (Clinus supercilious). In fact, this is the first time an Elthusa species has been recorded from any klipfish (genus Clinus).

To describe the new species, the scientists loaned all South African specimens identified as, or appearing to belong to the genus Elthusa from both the French National Museum of Natural History (Paris) and the Iziko South African Museum (Cape Town).

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Original source:

van der Wal S, Smit NJ, Hadfield KA (2019) Review of the fish parasitic genus Elthusa Schioedte & Meinert, 1884 (Crustacea, Isopoda, Cymothoidae) from South Africa, including the description of three new species. ZooKeys 841: 1-37. https://doi.org/10.3897/zookeys.841.32364

Scientific divers from the California Academy of Sciences discover new species of dazzling, neon-colored fish

Post originally published by the California Academy of Sciences

Named for Aphrodite, Greek goddess of love and beauty, a new species of fish enchants Academy scientists

On a recent expedition to the remote Brazilian archipelago of St. Paul’s Rocks, a new species of reef fish—striped a vivid pink and yellow—enchanted its diving discoverers from the California Academy of Sciences.

First spotted at a depth of 400 feet beneath the ocean’s surface, this cryptic fish inhabits rocky crevices of twilight zone reefs and is found nowhere else in the world. Upon discovery, the deep-diving team was so captivated by their finned find that they didn’t notice a massive sixgill shark hovering above them in an exciting moment captured on camera. The new fish description published today in Zookeys.

“This is one of the most beautiful fishes I’ve ever seen,” says Dr. Luiz Rocha, the Academy’s Curator of Fishes and co-leader of the Hope for Reefs initiative. “It was so enchanting it made us ignore everything around it.”

The sixgill shark stretched nearly ten feet long and cruised overhead as Rocha and post-doctoral fellow Dr. Hudson Pinheiro delicately collected the fish for further study back at the Academy. Behind the camera, the team’s diving officer Mauritius Bell enthusiastically announced the behemoth visitor to the duo, but to no avail. Aptly named, Tosanoides aphrodite enchanted its discoverers much like Aphrodite, Greek goddess of love and beauty, enchanted the ancient Greek gods.

“Fishes from the twilight zone tend to be pink or reddish in color,” says Pinheiro. “Red light doesn’t penetrate to these dark depths, rendering the fishes invisible unless illuminated by a light like the one we carry while diving.”

Back at the Academy, laboratory and collections manager Claudia Rocha helped the diving duo describe the new species: Males are outfitted with alternating pink and yellow stripes while females sport a solid, blood-orange color. Using a microscope, the team counted fins and measured spine length; DNA analysis revealed the new species is the first Atlantic-dwelling member of its genus.

Male specimen of the new species (Tosanoides aphrodite). Photo by LA Rocha.

The new denizen of the deep is a remarkable testament to the vast ocean habitats that still remain unexplored. Rocha and Pinheiro are part of a deep-diving research team that ventures to twilight zone reefs—mysterious coral habitats stretching across a narrow band of ocean 200 – 500 feet beneath the surface. In these deep reefs, animals live in partial darkness—beyond recreational diving limits, yet above the deep trenches patrolled by submarines and ROVs. As part of its Hope for Reefs initiative, the Academy team and their collaborators are exploring this unknown frontier with the help of high-tech equipment like closed-circuit rebreathers that allow scientists to extend their research time underwater.

Nearly 600 miles offshore the coast of Brazil, St. Paul’s Rocks is so remote that it required the team to utilize the research vessel M/V Alucia as their homebase to explore the archipelago. The rocky outcroppings are extensions of the Mid-Atlantic Ridge—an active, tectonic plate boundary—puncturing the ocean’s surface. Given the region’s unique geology and isolated location, many of the species that live there are found nowhere else on Earth. Through their research, the Hope for Reefs team is finding that twilight zone habitats also host many location-specific species.

In a recent landmark paper, the team found that twilight zone reefs are unique ecosystems bursting with life and are just as vulnerable to climate change threats as their shallow counterparts. Their findings upended the long-standing assumption that species might migrate between habitats to avoid human-related stressors. As documented in the footage from this new fish’s discovery, a piece of fishing line can be seen streaming behind the sixgill shark—evidence that human impacts extend to depth too.

“In a time of global crisis for coral reefs, learning more about unexplored reef habitats and their colorful residents is critical to our understanding of how to protect them,” says Rocha. “We aim to highlight the ocean’s vast and unexplored wonders and inspire a new generation of sustainability champions.”

 

Research article:

Pinheiro HT, Rocha C, Rocha LA (2018) Tosanoides aphrodite, a new species from mesophotic coral ecosystems of St. Paul’s Rocks, Mid Atlantic Ridge (Perciformes, Serranidae, Anthiadinae). ZooKeys 786: 105-115. https://doi.org/10.3897/zookeys.786.27382

How did the guppy cross the ocean: An unexpected fish appears on a volcanic archipelago

While people tend to describe tropical oceanic islands as ‘paradises on Earth’ and associate them with calm beaches, transparent warm waters and marvellous landscapes, archipelagos are often the product of a fierce natural force – volcanoes which erupt at the bottom of the sea.

Because of their origin, these islands have never been connected to the mainland, thereby it is extremely difficult for species to cross the ocean and populate them.DSCN1337

One such species – the South American guppy (Poecilia vivipara) – is a small freshwater fish which looks nowhere equipped to cross the distance between the mainland and the Fernando de Noronha oceanic archipelago in Northeast Brazil.

Nevertheless, the research team of PhD student Waldir M. Berbel-Filho and his professor Dr. Sergio Lima from Universidade Federal do Rio Grande do Norte recorded the species from a local mangrove on the island. The question that immediately sprang to the minds of the scientists was: ‘Where did the guppies come from and how did they get to Fernando de Noronha?’

To answer these questions, the scientists sequenced a gene of the guppies’ DNA to analyze potential signatures of the island colonization left in the fish DNA. As a result, they concluded that the isolated population was in fact closely related to the fish inhabiting the closest continental drainages.

However, this evidence was not enough to explain how the species turned up on the island in the first place. Was it natural colonization, or rather human introduction?

Poecilia vivipara Sergipe-2

The most likely scenario, according to the team, leads back to about 60 years ago when the American military had their WWII bases positioned at both Fernando de Noronha and Natal – the closest continental city. Indeed, the soldiers suggested to bring guppies to the island in an attempt to control mosquito population (in this region, guppies are commonly placed in water reservoirs to eat mosquito larvae).

On the other hand, natural dispersion cannot be completely excluded. The biologists remind that, apart for their exuberant colours and shapes, the guppies are well known for their capacity to resist to a wide range of environmental conditions. It could be that a set of circumstances occurring together, such as a favourable sea current, physiological adaptation and a bit of luck, might have brought the guppies to the archipelago.

Regardless of their means of transportation,” argue the authors, “this guppy population represents a valuable lesson on how small populations manage to colonize and thrive in isolated environments.

Despite being visited by thousands of people every year, some of the most intriguing secrets of tropical islands may still be hidden in the DNA of their inhabitants,” they conclude. “These ‘paradises on Earth’ are capable of simultaneously filling our hearts with beauty and our minds – with knowledge.”

 

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Original source:

Berbel-Filho WM, Barros-Neto LF, Dias RM, Mendes LF, Figueiredo CAA, Torres RA, Lima SMQ (2018) Poecilia vivipara Bloch & Schneider, 1801 (Cyprinodontiformes, Poeciliidae), a guppy in an oceanic archipelago: from where did it come? ZooKeys 746: 91-104. https://doi.org/10.3897/zookeys.746.20960

Chinese scientists discover a new species of catfish in Myanmar

During a survey of the freshwater fishes of the Mali Hka River drainage in the Hponkanrazi Wildlife Sanctuary, Myanmar, scientists Xiao-Yong Chen, Tao Qin and Zhi-Ying Chen, from the Chinese Academy of Sciences (CAS), identified a new catfish species among the collected specimens. It is distinct with a set of morphological features including its mouthparts and coloration. The discovery is published in the open access journal ZooKeys.

The new catfish belongs to a genus (Oreoglanis) of 22 currently recognised species. They are characterised with unusual teeth. While pointed in the upper and the back of the lower jaw, the teeth at the front of the lower jaw are shorter and broad. The latter are placed in a continuous dent. Out of the 22 species of the genus, there are only two known to live in Myanmar.

The new catfish, scientifically named Oreoglanis hponkanensis, has a moderately broad and strongly depressed head and body, and small eyes. The species is predominantly brown in colour, with light yellow belly and several yellowish patches across the body. Noticeable are also two round, bright orange patches in the middle of the fin.

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Original source:

Chen X-Y, Qin T, Chen Z-Y (2017) Oreoglanis hponkanensis, a new sisorid catfish from north Myanmar (Actinopterygii, Sisoridae). ZooKeys 646: 95-108. https://doi.org/10.3897/zookeys.646.11049

Undergraduate student takes to Twitter to expose illegal release of alien fish in Japan

Posing a significant threat to the native biodiversity in Japan, specifically that of threatened aquatic insects, some alien fishes, such as the bluegill, have become the reason for strict prohibitions. All activities potentially capable of introducing the species into the wild are currently punishable by either a fine of up to 3 million yen for a person (100 million yen for corporations), or a prison sentence of up to 3 years.

Recently, ten years after the law has been adopted, illegal release of bluegill fish has been reported for the first time with the help of a post on Twitter from Akinori Teramura, undergraduate student at the Tokyo University of Marine Science and Technology and second author of the present study. The case is reported and discussed by him and two scientists, affiliated with Kanagawa Prefectural Museum of Natural History, Japan, in the open-access journal ZooKeys.

In June 2015, Akinori Teramura tweeted two photographs of the invasive bluegill fish, both adults and juveniles, along with two young goldfish, which do not belong to the local fauna, either. In his post he identified the species and shared his surprise at the irresponsibility of the people who had released the fish. When lead author Dr Yusuke Miyazaki saw the tweet, he signalled his colleagues with the idea to publish the information as a scientific report.

The student found them in an outdoor public pool in Yokohama city, Japan, while it was being cleaned before being opened ahead of the summer. Usually, these facilities are closed to the public during the colder seasons and it is then when native aquatic insect species, such as dragonflies and diving beetles, find spawning and nursery habitats in them. Curiously enough, though, the pool had been isolated from natural waters since its construction.

7577_ZK_Data-mining and Twitter img3

Therefore, the researchers conclude that the alien fishes have most likely been released from an aquarium from a local shop or an aquarist who no longer wanted them. However, the authors note that according to the law, keeping bluegill fish in a home aquarium is illegal as well.

“Our report demonstrates an example of web data mining in the discipline of Citizen Science,” say the authors. “Web data mining has been rapidly developing over recent years, and its potential continues to expand.”

“Community awareness of this issue needs to be improved, and widespread reporting of cases such as this one will help,” they conclude.

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Original source:

 

Miyazaki Y, Teramura A, Senou H (2016) Biodiversity data mining from Argus-eyed citizens: the first illegal introduction record of Lepomis macrochirus macrochirus Rafinesque, 1819 in Japan based on Twitter information. ZooKeys 569: 123-133. doi: 10.3897/zookeys.569.7577