Crayfish ‘trapping’ doesn’t control invasive species

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Oct. 13 (UPI) — In Britain, a handful of celebrity chefs have encouraged the practice of crayfish “trapping” to control the invasion of American signal crayfish.

Unfortunately, new research — published Tuesday in the Journal of Applied Ecology — suggests the practice doesn’t work. In fact, crayfish trapping can have a host of unintended consequences.

“Trapping has been linked to a range of risks to our waterbodies, including the spread of invasive species on wet or unclean equipment, as well as the direct capture and release of invasive crayfish to seed new harvestable populations,” study co-author Eleri Pritchard told UPI in an email.

“Sadly, trapping also risks protected native wildlife, and has been responsible for the deaths of otters and water voles,” said Pritchard, a postdoctoral researcher at University College London.

American signal crayfish have led to significant declines of native crayfish in Britain and Europe. The invasive species is a carrier of what’s called crayfish plague, a disease that is lethal to the native white-clawed crayfish. American signal crayfish are also bigger and more aggressive than native species, outcompeting them for available resources.

Beyond threatening native species, American signal crayfish also burrow into stream banks, undermining natural stream structures and increasing flood risks. Researchers suggest the invasive species also poses a threat to fish, invertebrates and aquatic plants.

Taking a cue from efforts to curb the spread of invasive fish species, chefs in Britain have encouraged people to trap and eat American signal crayfish.

“Crayfish trapping involves the use of funnel traps, very similar to lobster pots,” Pritchard said. “The traps are submerged in the water and baited with something to attract the crayfish, like fresh oily fish or cat-food. This entices the crayfish through the funnel entrances of the trap and once inside, it is difficult for them

First scientific description of a previously unknown Streptococcus species of Chacoan peccaries — ScienceDaily

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The species richness of zoo and wild animals is reflected in the diversity of infectious agents they harbour. However, our knowledge is sparse and pathogen detection remains challenging. For streptococci, a bacterial family of importance to human and animal health, wildlife research has taken a step forward: A research team led by Kristin Mühldorfer from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) and Tobias Eisenberg from the Hessian State Laboratory investigated the causes of severe respiratory disease in peccaries and taxonomically characterised a novel Streptococcus species (Streptococcus catagoni sp. nov.) based on its phenotypic properties and genetic features. The results, published in the International Journal of Systematic and Evolutionary Microbiology, contribute to a better understanding and reliable identification of this novel bacterial species.

The family Streptococcaceae consists of bacteria inhabiting the skin and mucous membranes and includes important pathogens. Despite Streptococcus species with a broad host range infecting humans and vertebrates, the family includes bacterial species that seems to be exclusively adapted to certain hosts or habitats, such as Streptococcus castoreus of beavers, Streptococcus didelphis of certain marsupial species or Streptococcus phocae of marine mammals and fish.

In the present paper the authors analysed a previously unknown Streptococcus species that was responsible over two consecutive years for severe disease in a group of Chacoan peccaries (Catagonus wagneri) kept in a zoo. Animals were mainly affected within the first year of life and showed suppurative infections of the upper and lower respiratory tract. At least five peccaries had died from the infection. The novel bacterial species has been named according to its origin as Streptococcus catagoni sp. nov.

“These are the first confirmed cases in Chacoan peccaries,” says Dr Kristin Mühldorfer, scientist from the Leibniz-IZW. The Chacoan peccary is an endangered species that shows a continuing decline in

Newly found dinosaur fossils shed light on toothless, two-fingered species

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Here’s a look at what the Oksoko avarsan dinosaurs might have looked like way back when.


Michael W. Skrepnick

Newly discovered fossils of a toothless, parrot-like dinosaur species that lived more than 68 million years ago reveal a creature with two fingers on each forearm. That’s one less digit than its close dino relatives had. 

The fossils imply that the dinosaurs may have evolved forelimb adaptations that enabled them to spread during the Late Cretaceous Period, researchers say in a new study published Wednesday in The Royal Society Open Science journal. Paleontologists from the University of Edinburgh found a number of complete skeletons of the new species during a dig in Mongolia’s Gobi Desert. 

The feathered, omnivorous Oksoko avarsan grew to around 6.5 feet (2 meters) long. In addition to two functional digits on each forearm, the dinosaurs appeared to have large, toothless beaks, much like modern-day parrots. 

“Its two-fingered hand prompted us to look at the way the hand and forelimb changed throughout the evolution of oviraptors — which hadn’t been studied before,” University of Edinburgh professor and study co-author Gregory Funston said in a statement. “This revealed some unexpected trends that are a key piece in the puzzle of why oviraptors were so diverse before the extinction that killed the dinosaurs.”

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The fossil of an Oksoko avarsan’s two-fingered hand.


Gregory Funston

The dinosaurs’ arms and hands changed dramatically during slow migrations to new geographic areas in the Gobi Desert and North America.

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The fossil remains of three dinosaurs preserved resting together.


Gregory Funston

The newly discovered fossils of four young Oksoko avarsan dinosaurs show them resting together, which the scientists think may be further proof the dinosaurs were social as juveniles. 

“Oksoko avarsan

Extinctions linked to new assemblages of species — ScienceDaily

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Scientists have found that as the world undergoes profound environmental change, identifying and protecting ‘novel’ communities of species can help prevent extinctions within vulnerable ecosystems.

Professor John Pandolfi and Dr Timothy Staples from the ARC Centre of Excellence for Coral Reef Studies at The University of Queensland (CoralCoE at UQ) are the lead authors of a new study in Science that looked at how combinations of plankton species changed across the world’s marine ecosystems in the past 66 million years. From this, their team developed a world first method to detect ‘novel’ communities of species across all ecosystems.

“A novel ecological community is one with combinations of species that are different to any past observations from that site,” Prof Pandolfi said. “These different species combinations can be due to new species arriving in the community, existing species leaving, or species becoming rarer or more common.”

“We found that when novel communities formed, existing species were twice as likely to disappear from the community permanently, representing a ‘local’ extinction.”

“Species in the novel community were also more likely to be new arrivals that had never been observed in the community before.”

An example of a modern novel community is the coral reefs of the Caribbean, where the two once dominant species of branching coral are now rare. Those reefs are now home to new, or novel, communities of corals. The loss of the branching corals is due to the impacts of overfishing, changes in water quality, and climate change — resulting in new configurations of coral species within the Caribbean reef communities. And the shift means the benefits of the reef are now different: different species means different inhabitants and functions.

“The challenge is to manage at risk or vulnerable areas like this where novel communities exist, or where they’re in

Seasonal dietary changes increase the abundances of savanna herbivore species — ScienceDaily

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African savannas are renowned for their huge diversity of wildlife, yet some animal species are much more abundant than others. What causes these differences?

For herbivore species — plant-eating animals like antelope, zebra and elephants — the challenge lies in both obtaining enough food to eat throughout the year, while also avoiding predation by carnivores.

One way to obtain enough food — and which works extremely well in places like the Serengeti — is to migrate over long distances and track the areas where the best food is available through the seasonal cycle. This works best for grass eating or ‘grazer’ species such as wildebeest and zebra.

On the other hand, being extremely large like an elephant greatly reduces predation risk, with their big bodies also meaning that they can eat whatever they like, because there is lots of time to digest foods as they move through their long gut system.

So why then are impala by far the most abundant herbivore in a place like the Kruger Park? These are animals that do not migrate, and they are also only medium-sized at best.

Recent research published in Science Advances by Professor Carla Staver from Yale University and Dr Gareth Hempson from University of the Witwatersrand has shed new light on this question.

“The key insight emerging from our research is that species like impala do actually migrate, although not in the sense you would expect,” says Dr Hempson. “For impala, the migration they undertake is a ‘dietary migration’, where they switch from eating mostly grass in the wet season, to eating more tree leaves or ‘browse’ during the dry season. This ‘mixed feeding’ strategy makes a huge amount of sense, because grasses tend to be higher quality and more abundant food in the wet season, but trees tend to