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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 to escape. The traps are then retrieved from the water with crayfish trapped inside.”

For the new study, researchers compared the effectiveness of three survey methods — baited funnel trapping, hand-searching and a novel “triple drawdown technique” — deployed to analyze local crayfish populations. The triple drawdown method involves the draining of a short section of stream in order to tally the number of crayfish present, including infants.

The triple drawdown technique proved most effective at providing scientists a comprehensive and precise picture of the size and makeup of crayfish population within a stream. The method showed crayfish population densities have likely been underestimated in many British streams.

The novel survey method also showed that only a small percentage of any given stream’s American signal crayfish is trappable. Most of the invasive crayfish are too small.

“In our research, [the triple drawdown technique] helped us understand how trapping would not be effective at controlling populations, which is really important for management and conservation,” Pritchard said.

Researchers are currently working to develop effective American signal crayfish control methods.

In the meantime, Pritchard and her colleagues suggest prevention of the spread of both crayfish and the crayfish plague is essential for the protection of native crayfish.

“Please disinfect all gear when traveling between waterbodies,” Pritchard said.



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NASA’s OSIRIS-REx touches down on asteroid Bennu to nab sample

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Oct. 20 (UPI) — NASA’s OSIRIS-REx touched down on asteroid Bennu on Tuesday evening in a mission to scoop a sample of rocks and dirt.

The spacecraft — the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer — made soft contact with the asteroid at 6:12 p.m. EDT.

The historic “touch and go” event featured animation displaying OSIRIS-REx’s sample collection activities in real time. It takes time for real images of the touchdown to travel back to the Earth, so they won’t be released to the public until Wednesday.

The craft executed a series of maneuvers over the course of several hours before making soft contact with the surface of the asteroid to collect regolith, or rocks and dirt.

“It will be four and a half hours of anxiousness,” Beth Buck, OSIRIS-REx mission operations manager at Lockheed Martin Space, said in a news conference ahead of the event.

Buck made a comparison to the descent of a spacecraft on Mars, when there is typically “seven minutes of terror.”

The goal is to learn more about the solar system’s history and help “planetary defense” engineers with missions to protect earth from rogue asteroids. Bennu is believed to be a window into the solar system’s past since it’s a pristine, carbon-rich body carrying building blocks of both planets and life.

At around 1:50 p.m. EDT, the spacecraft left orbit around the asteroid before executing a series of burns to position itself over a sampling area nicknamed Nightingale.

Once in position, the craft began its approach to the asteroid at 5:50 p.m. EDT. It then spent about 15 seconds attempting to collect the regolith sample before backing away again.

The area, which is 52 feet in diameter, will make for a more demanding landing than expected, Kenneth Getzandanner, OSIRIS-REx flight dynamics manager at the NASA Goddard Space Flight Center in Maryland, said in the news conference.

The original mission called for a landing “zone” about 150% larger than Nightingale, at 82 feet, but that changed because Bennu was more rocky than expected.

The goal was to collect at least 1.7 ounces of fine-grained material, but the spacecraft can carry up to 4.4 pounds, Heather Enos, OSIRIS-REx deputy principal investigator at the University of Arizona said.

“I would love for that capsule to be completely full,” Enos said.

Though early images from the asteroid should hint at whether the mission succeeded, it will take engineers roughly 10 days to compare and analyze the mass before and after the maneuver to actually know how much dirt is inside the OSIRIS-REx.

If it failed, the spacecraft has enough fuel to attempt two more touch downs to collect material.

The spacecraft is expected to return to Earth, with the regolith sample from Bennu, in 2023.



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SpaceX scrubs Starlink launch until Thursday, if weather cooperates

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Oct. 21 (UPI) — Just three days after sending 60 more Starlink satellites into orbit, SpaceX is aiming to launch another batch of broadband satellites into space from Florida.

If the weather cooperates, Thursday’s launch will be SpaceX’s 15th Starlink mission.

Liftoff had been scheduled for 12:29 p.m. EDT Wednesday aboard a Falcon 9 rocket at Launch Complex 40 at Cape Canaveral Air Force Station, but controllers scrubbed the launch due to weather and rescheduled for 12:14 p.m. on Thursday.

With a launch Sunday, SpaceX increased the size of their Starlink constellation to nearly 800 satellites. The 15th mission will see another 60-odd satellites join the network.

“The goal of Starlink is to create a network that will help provide Internet services to those who are not yet connected, and to provide reliable and affordable Internet across the globe,” according to the Kennedy Space Center.

Weather for Wednesday’s planned launch had looked so-so and the Space Force’s 45th Weather Squadron predicted a 60 percent chance of favorable conditions.

“A mid-level inverted trough and associated easterly wave currently across the Bahamas will meander into the state over the next few days, bringing enhanced moisture, cloud cover, and instability with a higher coverage of showers and storms,” Space Force forecasters wrote.

They said Thursday’s forecast looks quite similar to Wednesday’s.

Earlier this month, SpaceX founder and CEO Elon Musk tweeted that Starlink’s constellation was big enough to begin beta-testing the Internet service system in both the United States and southern Canada.

SpaceX has already offered Starlink Internet services to emergency responders in wildfire-stricken areas of Washington State.

Washington’s Hoh tribe is also using the Internet service to provide their members online education and telehealth services.



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Chernobyl-level radiation harms bumblebee reproduction

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Oct. 21 (UPI) — Bees are more sensitive to radiation than scientists thought. Scientists found the reproduction rates of bumblebees declined significantly when exposed to Chernobyl-level radiation.

The research, published Wednesday in the journal Proceedings of the Royal Society B: Biological Sciences, suggests radiation in Ukraine’s Chernobyl Exclusion Zone could impair pollination services, triggering wider ecological consequences than previously estimated.

Humans are not allowed to live in the Chernobyl Exclusion Zone, the disaster area more directly impacted by the 1986 nuclear accident, the worst in history. However, the destroyed nuclear reactors are surrounded by forests that are populated by robust populations of birds, bears, bison, lynx, moose, wolves and more.

Efforts to gauge the effects of radiation contamination on insects have yielded mixed results in the past. While some studies have suggested insects are relatively radiation-resistant, others have demonstrated significant impairment.

When researchers exposed bumblebees in the lab to radiation dose of 100 µGyh-1, an amount approximating exposure inside the Chernobyl Exclusion Zone, reproduction rates among the bees dropped between 30 and 45 percent.

Researchers found a direct correlation between the size of the radiation dose and reproduction rate declines. Lower levels of radiation had a smaller effect, while larger doses yielded greater declines.

Scientists were surprised to find they were able to detect reproductive rate declines at very small levels of radiation exposure.

“Our research provides much needed understanding as to the effects of radiation in highly contaminated areas and this is the first research to underpin the international recommendation for the effects of radiation on bees,” lead study author Katherine Raines, environmental scientist at the University of Stirling in Scotland, said in a news release.



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