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Posts Tagged ‘science

[LINK] “Keeping Farm Fish Locked Up Keeps Ecosystem Calamity at Bay”

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Brendan I. Koerner in Wired looks at how aquaculture specialists are trying to limit the potential environmental danger of aquaculture.

Aquaculture is fast becoming the main way that humans get their seafood fix. But fish aren’t cattle; they don’t turn passive when cooped up. Every year, hundreds of thousands of salmon, cod, and rainbow trout wriggle through damaged or defective cages and flee into the open seas, never to be recaptured. In addition to costing farmers millions in lost revenue, these escapees can wreak havoc on their wild brethren by polluting gene pools and spreading pathogens.

To prevent that sort of environmental calamity, Trine Thorvaldsen is studying how best to keep farmed fish from going on the lam. A labor health and safety expert at a Norwegian research institute, Thorvaldsen recently set out to determine why her country loses around 200,000 captive salmon per year. In addition to analyzing reams of incident reports and industry statistics, she also convinced numerous farmers to speak to her anonymously—no small feat in Norway, where allowing fish to escape is a criminal offense with stiff penalties. Her research has led her to conclude that avoidable human errors play a key role in Norway’s’ salmon escapes.

“There was one instance in which fish were being pumped from one cage to another, but the workers didn’t realize there was no net to keep them,” says Thorvaldsen, who is a cultural anthropologist by training; by the time anyone noticed the silly mistake, 13,000 salmon had swum away. Most of the fateful miscues that lead to mass “fishbreaks,” however, are less spectacular in nature. Workers sometimes have difficulty operating equipment, for example, and brush the vessels’ destructive propellers against the containment nets. Or they inadvertently tear those nets while using cranes to adjust the weighted tubes that maingtain the shape of underwater cages. Farmers are often unaware of these small fissures until hours later, at which point it’s often too late to dispatch recovery teams to the site. They must instead keep their fingers crossed that nearby fishermen will catch the piscine escapees before they start to interbreed with wild fish. (To encourage the recapture of escaped salmon, Norwegian cultivators have been known to offer 60-euro-per-fish bounties.)

For many years, fish farmers have pined for a technological solution to their escape problem: an alarm that can be wired into the nylon nets, to alert workers when tears are beginning to develop. But such a system has proven tough to invent and implement, largely because saltwater doesn’t play well with electrical wires. With no reliable alarm on hand, Thorvaldsen instead urges farmers to curtail errors by adhering to some common-sense workplace policies. These include making sure that laborers don’t work past the point of mental exhaustion, suspending operations when harsh weather or darkness approach, and insisting that all critical maintenance instructions be put down in writing rather than squawked over fuzzy radio channels. Thorvaldsen also wants managers to understand that certain delicate fish-farming procedures, such as using cranes, should never be rushed.

“We’ve had a lot of workers say, ‘We are under a lot of pressure, we have to do things fast, we have to deliver the fish when the boat’s there,’” Thorvaldsen says. The net tears that can result from such haste are what farmed fish dream of when they sleep.

Written by Randy McDonald

June 26, 2015 at 10:27 pm

[LINK] “Wolves are better hunters when monkeys are around”

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Science Daily reports on an interesting research finding from Ethiopia.

Through extensive data collection from all-day follows on the Guassa Plateau in north central Ethiopia from 2006 to 2011, researchers studied a band of approximately 200 gelada monkeys, who regularly associate with the wolves living in the area.

According to the study’s findings, gelada monkeys would not typically move upon encountering Ethiopian wolves, even when they were in the middle of the herd — 68 percent of encounters resulted in no movement and only 11 percent resulted in a movement of greater than 10 meters. In stark contrast, the geladas always fled great distances to the cliffs for safety whenever they encountered aggressive domestic dogs.

The Ethiopian wolves experienced a foraging advantage on subterranean rodents when among the gelada monkeys — Ethiopian wolves foraged successfully in 66.7 percent of attempts among the gelada monkeys v. a success rate of only 25 percent when wolves foraged by themselves. The success rate may be attributed to the rodents being flushed out by the monkey herd, which disturb the vegetation as they graze or to what may be a diminished ability for the rodents to detect predators due to a visual or auditory interference posed by the grazing monkeys.

Written by Randy McDonald

June 23, 2015 at 10:55 pm

Posted in Science

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[LINK] “There are goldfish the size of dinner plates turning up in Alberta, biologists say”

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Postmedia News’ Alexandra Zabjek writes in the National Post about invasive life in the waterways of Alberta.

The discovery of dinner plate-sized goldfish and the ongoing threat of a zebra mussel infestation has the Alberta government ramping up awareness of invasive aquatic species in provincial water bodies.

The zebra mussel, which multiplies prodigiously and can clog water pipes, has been the “poster child” for invasive aquatic species. But seemingly mundane creatures can cause problems, too.

“The mussels really scare the crap out of everyone — biologists because of the environmental impacts. And the irrigation industry, the hydropower industry, the waste water treatment industry all potentially have a lot to lose,” said Kate Wilson, an aquatic invasive species specialist with Alberta Environment and Parks.

“It’s a big, scary thing to really engage the public. I’m hoping to use that to get people to think about how … people are dumping their goldfish, which is pretty serious for a whole lot of other reasons.”

Wilson recounted the story of a fisheries biologist who last year saw two children fishing in a Fort McMurray stormwater pond. The biologist discovered they had caught two goldfish, and the municipality then hired a consultant to study the pond.

More, including photos, at the site.

Written by Randy McDonald

June 23, 2015 at 10:53 pm

[LINK] “Ancient Romanian jawbone sheds light on Neanderthal interbreeding”

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The Globe and Mail hosts Will Dunham’s Reuters article reporting that an ancient Homo sapiens skeleton in Romania has substantial Neanderthal ancestry. That this skeleton does not belong to a population that left descendants in contemporary Europe is also noteworthy, IMHO.

You may not know it, but you probably have some Neanderthal in you. For people around the world, except sub-Saharan Africans, about 1 to 3 percent of their DNA comes from Neanderthals, our close cousins who disappeared roughly 39,000 years ago.

Scientists said on Monday a jawbone unearthed in Romania, of a man who lived about 40,000 years ago, boasts the most Neanderthal ancestry ever seen in a member of our species.

[. . .]

“We show that one of the very first modern humans that is known from Europe had a Neanderthal ancestor just four to six generations back in his family tree,” said geneticist Svante Pääbo of Germany’s Max Planck Institute for Evolutionary Anthropology.

“He carries more Neanderthal DNA than any other present-day or ancient modern human seen to date.”

Harvard Medical School geneticist David Reich said 6 to 9 percent of this individual’s genome derived from a Neanderthal ancestor.

Written by Randy McDonald

June 22, 2015 at 7:04 pm

[LINK] “Is Salmon Raised on Land the Future of Seafood?”

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Joaquin Palomino at National Geographic describes how the Namgis First Nation on Vancouver Island is pioneering environmentally sustainable aquaculture based on land.

For centuries, perhaps millennia, the Namgis First Nation fished a wide and glassy river that barrels into the straits separating Vancouver Island from mainland Canada. According to legend, sockeye salmon were so plentiful that the Namgis could simply redirect the river and trap seemingly endless runs of fish in ponds outside their homes.

Today, sockeye have all but disappeared from the Nimpkish. But a stone’s throw away, a warehouse brims with hundreds of thousands of Atlantic salmon. The fish crowd into pools the color of jade, swim against a steady current, eat pellets that rain down from metal pipes above, and grow plump.

This $7.6 million (U.S.) warehouse is called Kuterra. Owned by the Namgis, it is one of the few commercial-scale, land-based salmon farms in the world. Considered a model for sustainable aquaculture, Kuterra recycles its water, converts its waste into fertilizer, avoids use of pesticides and antibiotics, and relies predominantly on grains and soy for fish food.

“The one word that best describes what we’re doing here is ‘control,’ ” says Jo Mrozewski, a company spokesperson. “You control the environment, you control the growth parameters. You can control so many things because you’re not exposed to the vagaries of nature.”

Roughly 600,000 pounds of Kuterra salmon have been sold since the company’s first harvest 14 months ago, and after receiving the Monterey Bay Aquarium’s “Best Choice” sustainability rating in October, consumer demand has surpassed supply. The fish respond well to the highly regulated system: They grow nearly twice as fast as other farmed Atlantic salmon, and they eat much less food.

Written by Randy McDonald

June 15, 2015 at 10:20 pm

[CAT] “What Cats Taught Us About Perception”

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Via lostmuskrat and Laughing Squid, I came across a clip from the PBS Digital Studios show Brain Craft where host Vanessa Hill explains the significant role that cats played in the discovery of the dynamics of vision.

Written by Randy McDonald

June 13, 2015 at 11:07 pm

Posted in Science

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[LINK] Two notes on chimpanzees who drink and have pet dogs

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Al Jazeera reported this from a study of chimpanzees in Guinea-Bissau.

During a 17-year study, chimps in the West African country of Guinea were observed on numerous occasions imbibing a fermented milky sap from raffia palms, tapped by local people to make into an alcoholic drink.

Incidents of lone drinkers and communal sessions were seen, according to a paper published in the British journal Royal Society Open Science.

Researchers suggested the findings give insight into the social habits of chimpanzees in the wild. They also back the “drunken monkey” theory, which holds that apes and humans share a genetic ability to break down alcohol that was handed down from a common ancestor.

Under observation, the apes scrunched up leaves in their mouths, molding them into spongy pads that they then dipped into the sap-gathering container, which villagers attach to the tree near its crown.

Tests showed that the beverage’s alcoholic content varied from 3.1 percent to 6.9 percent — the equivalent of strong beer.

Meanwhile, the New Scientist noted that gelada baboons in eastern Africa appear to have domesticated wolves.

In the alpine grasslands of eastern Africa, Ethiopian wolves and gelada monkeys are giving peace a chance. The geladas – a type of baboon – tolerate wolves wandering right through the middle of their herds, while the wolves ignore potential meals of baby geladas in favour of rodents, which they can catch more easily when the monkeys are present.

The unusual pact echoes the way dogs began to be domesticated by humans [. . .], and was spotted by primatologist Vivek Venkataraman, at Dartmouth College in New Hampshire, during fieldwork at Guassa plateau in the highlands of north-central Ethiopia.

Even though the wolves occasionally prey on young sheep and goats, which are as big as young geladas, they do not normally attack the monkeys – and the geladas seem to know that, because they do not run away from the wolves.

“You can have a wolf and a gelada within a metre or two of each other and virtually ignoring each other for up to 2 hours at a time,” says Venkataraman. In contrast, the geladas flee immediately to cliffs for safety when they spot feral dogs, which approach aggressively and often prey on them.

When walking through a herd – which comprises many bands of monkeys grazing together in groups of 600 to 700 individuals – the wolves seem to take care to behave in a non-threatening way. They move slowly and calmly as they forage for rodents and avoid the zigzag running they use elsewhere, Venkataraman observed.

Written by Randy McDonald

June 11, 2015 at 10:51 pm


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