Fish Success Story: Cod Makes a Comeback

By Katharine Gammon | Takepart.com October 27, 2015 4:54 PM TakePart.com

Fish Success Story: Cod Makes a Comeback

The cod is coming back.

The species that was for centuries a mainstay of the American and Canadian economies had virtually vanished off the Northeastern North American coast by the 1990s owing to overfishing. That led regulators in 1992 to impose a moratorium on cod fishing.
It appears to have worked.
New research shows that cod biomass has increased from the tens of tons to more than 200,000 tons within the last decade. This spring, scientists documented large increases in cod abundance and size for the first time since the moratorium in the more northerly spawning groups, according to a study published Monday in the Canadian Journal of Fisheries and Aquatic Sciences.
“Cod was historically one of the most important fish stocks in the world,” said George Rose, director of the Center for Fisheries Ecosystems Research at the University of Newfoundland in Canada and author of the new report on the cod’s recovery. “When the stocks collapsed in the 1990s, it became the icon of all the bad things we are doing to the ocean, and in many ways, it changed how we deal with our oceans worldwide.”
For hundreds of years, cod were so common—and so huge—that people reported being able to walk across their backs. Cape Cod was named after the fish, and salt cod is credited with sustaining explorers crossing the Atlantic from Spain and Iceland.
When the fishing ban took effect, cod had dwindled to  5 percent of its historic biomass. The moratorium threw 22,000 fishers and processing plant threw employees in more than 400 coastal communities in the United States and Canada out of work.
RELATED: Google Wants You to Fight Overfishing
The moratorium played a big part in the cod’s recovery, as did the return of the fish’s food source, according to the study.
Around the time that cod stocks crashed, a parallel collapse occurred in populations of plankton and capelin, a small smelt fish that provides sustenance for larger fish. “Capelin are the main conduit of energy, from plankton right up to the top of the food chain,” said Rose. “We still don’t know exactly why, but it was really uncertain whether cod could survive the changes at all.”
The first hint of the comeback came in 2008, when researchers saw regrouping of cod on their breeding grounds along with the return of the capelin.
The reasons for the return of the capelin are a mystery, but Rose said it pointed to the need for a more comprehensive approach to fishery management. “This is one of the most important examples why we need to understand the full ecosystem and not just the stocks of fish,” he said.
Cod’s future is still in question. Stocks are low in New England and other parts of the fish’s range where the ocean is warming. But in more northern areas, it is thriving.

He said there are indications that climate change will increase cod populations in Newfoundland and other northern regions.

But don’t expect cod on your dinner plate anytime soon. The Canadian fishing ban remains in place, and the U.S. has also tightened restrictions on cod fishing.

“Nature has kind of given us a second chance,” Rose said. “We don’t want to blow it this time.”

Scientists discover furry new post-apocalyptic critter that survived demise of the dinosaurs

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By Sarah Kaplan October 5

A rendering of Kimbetopsalis. (Sarah Shelley)

 

Sixty-six million years ago, a chunk of space rock the size of a mountain slammed into the Earth. The planet would never be the same.
Debris from the impact went flying into the air, forming clouds so thick they blocked out the sun. Earthquakes shook the ground and sent massive tsunami waves roiling toward shorelines. At the same time — maybe unrelated to the impact, maybe exacerbated by it — a vast flow of lava was flooding across India, oozing ash and noxious gases that caused the climate to fluctuate like a yo-yo and may have helped kill off anything that survived the initial cataclysm.
It was not a good time to be alive, and most species made a swift exit from the global stage: Vegetation withered. Ocean life gasped for air and energy, then collapsed. Gone were the fearsome Tyrannosaurus, the winged Pterosaurs, the massive Triceratops with its three horns and bony neck frill. The dinosaurs’ 100 million-year reign had ended. And when the smoke cleared, a new hero had taken over.
It was buck-toothed and furry and had the goofy appearance of a character from a children’s cartoon. Instead of Earth-shaking stomps, it likely moved with a rodent’s fearful scurry.
Its name is Kimbetopsalis simmonsae, scientists say in a paper published Monday in the Zoological Journal of the Linnean Society. And although it was only about three feet long and no more intimidating than a beaver, it was one of the largest animals around. If Tyrannosaurus was the king of the Cretaceous, Kimbetopsalis was early royalty during the millennia that followed — an era we now call the “Age of the Mammals.”
Kimbetopsalis, which was recently discovered among the shifting sands and spooky rock formations of New Mexico’s badlands, was something of an evolutionary dark horse. First born in the Jurassic period, the fuzzy creature (creatures really — Kimbetopsalis represents a whole new genus) bided its time for a million centuries while dinosaurs tromped about.
After the meteorite-induced apocalypse, “all this ecological space became available and the mammals went a bit nuts,” explained Sarah Shelley, a paleontologist at the University of Edinburgh and a co-author on the paper.
Almost no one went more nuts than Kimbetopsalis, which grew from tiny proportions to the size of a very large beaver over the course of just 500,000 years — a mere blink of an eye in evolutionary terms. Paleontologists believe it had a beaver’s broad face and chunky frame as well, though it lacked a paddle-like tail. 
Though it looks like a rodent, Kimbetopsalis has no living descendants. But it is one of the longest-living groups of mammal in history: its 160-million-year run is longer than that of any mammal species alive today.

The teeth of Kimbetopsalis are pictured in this undated handout photo provided by Tom Williamson. (Tom Williamson/Handout via Reuters)

 

Proof of Kimbetopsalis’s existence comes from a few teeth and a fragment of skull discovered during an archaeological dig in a remote New Mexico desert last summer. The fossils were uncovered by Carissa Raymond, a sophomore at the University of Nebraska out on her first dig.
Raymond had never even taken a mammal biology class and had no formal training in fossil finding at the time. But when she called over project leader Thomas Williamson, curator at the New Mexico Museum of Natural History and Science, he “grinned right away,” Shelley recalled.
A new genus had just been discovered.
‭“It’s rare for anybody to find one of these,” Williamson said in a University of Nebraska press release. “I wish I had found it.” ‬ ‭
Teeth are some of the most telling fossils you can find when identifying a new species, Shelley explained — they’re the best indicators of what an animal ate, and what you eat pretty much determines everything about you. From those fragments, Shelley and her colleagues gained a rough understanding of how the ancient mammal looked and lived.
Though it’s now a dry and dramatic desert, at the time New Mexico would have been a lush semitropical forest, full of sustenance for an enterprising young herbivore. Kimbetopsalis had huge, knife-like incisors were ideal for gnawing on plants. And though predators certainly existed, very distant predecessors of modern cattle and horses, life would have been a lot safer than it was before the end-Cretaceous extinction.
Kimbetopsalis was among the biggest, but it was hardly the only mammal to flourish in the newly dinosaur-free world. After epochs of living in the shadows of their larger, lizard-like contemporaries, the early years of what’s now called the Palaeogene period saw the rise of hoofed animals and opossum-like marsupials, bats and even early primates. It pays, it would seem, to be small, good at hiding and willing to wait for a meteorite to wipe out your competitors.
The rapid growth and proliferation of the Kimbetopsalis is a testament to the power of environmental change and the persistence of early mammals, researchers say.
“The history of life hinges on moments that can reset the course of evolution,” Stephen Brusatte, a professor of vertebrate paleontology at the University of Edinburgh and another co-author on the paper, wrote in an essay for the Conversation. Amid the destruction and rapid change caused by the meteorite impact, “dinosaurs couldn’t cope and all of a sudden they were gone. Their size and strength couldn’t save them. Mammals fared better, and now one species of brainy ape occupies that dominant place in nature that was once held by the dinosaurs.”

The fieldwork team (L to R): Sarah Shelley, Eric Davidson, Carissa Raymond, Steve Brusatte, Ross Secord, are pictured in this undated handout photo, taken in New Mexico and provided by Tom Williamson.  (Tom Williamson/Handout via Reuters)

Scientists suggest a new, earth-shaking twist on the demise of the dinosaurs

By Joel Achenbach October 19

 

 

An illustration of the Chicxulub impact on the Yucatan Peninsula in Mexico, seen from 100 kilometers (km) altitude. (D. van Ravenswaay/Photo Researchers, Inc)

New research suggests that the asteroid or comet that slammed into the Earth 66 million years ago rocked the planet so violently that it accelerated a massive volcanic eruption in India, a double catastrophe that wiped out the dinosaurs and 70 percent of the Earth's species.
The study, published Thursday in the journal Science, puts a twist on the consensus explanation of the mass extinction at the end of the Cretaceous period. Scientists have long been confident that a mountain-sized object crashed into the planet, leaving traces even today of a vast crater at the tip of Mexico's Yucatan peninsula.
[Don’t worry. Matt Damon won’t get stuck on Mars. NASA can’t get him there.]
They’ve also known that massive volcanism in India was happening around the same time, spreading lava across a huge region known as the Deccan Traps. The coincidence of those two events initially hinted at causality, but subsequent dating of the Deccan Traps formations indicated that the flood of basaltic lava began long before the cataclysmic impact.

With the new data, causality's once again in play. The asteroid or comet didn’t cause the initial eruption, but it could have intensified it, according to the paper.
The Chicxulub impact – named after a town in the Yucatan – created earthquakes of magnitude 11 in the vicinity of the crater, the authors say. Magnitude 9 earthquakes would have been felt around the planet, they say.
[A ‘lost world’ of dinosaurs thrived in the snowy dark of Alaska]
The seismic energy made the planet's crust more permeable. Molten rock deep in the interior began flowing through fractures. As that magma expanded, gasses in the solution began forming bubbles. As with a shaken soda bottle, the results were likely explosive.
“Once that’s initiated, it becomes a kind of runaway process,” said Paul Renne, a University of California, Berkeley geologist and lead author of the new paper.

First ever evidence of a swimming, shark-eating dinosaur

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When it wasn't putting T. rex to shame, the dinosaur Spinosaurus spent its time swimming -- and chowing down on sharks.
Until now, scientists didn't have any proof that there were swimming dinosaurs. There were some marine reptiles prowling the seas, to be sure, but paleontologists couldn't find fossils that put dinosaurs in the water.
New fossil evidence published Thursday in Science changes that, and the  Spinosaurus aegyptiacus is breaking records left and right. It's now the largest predatory dinosaur to have ever roamed the planet — nearly 10 feet longer than the largest T. rex specimen — although the carnivore was still dwarfed by some of its plant-eating contemporaries. But more importantly, Spinosaurus has the distinction of providing our first ever evidence for a semi-aquatic dinosaur.

Spinosaurus was discovered in the Sahara more than a century ago by German paleontologist Ernst Freiherr Stromer von Reichenbach, but all of his fossils were destroyed during World War II.
When a partial skeleton was uncovered in the Moroccan Sahara -- in a place once home to a massive system of rivers full of all sorts of sharks and other predators  -- scientists had a new clue that there was something fishy about the massive dino.
In addition to revealing a record-breaking length, digital modeling of the skeleton suggested a whole fleet of aquatic adaptations. Tiny nostrils, placed far back on the middle of the dinosaur's skull, presumably allowed it to breathe as it swam at the surface. It also had openings at the end of its snout that are reminiscent of ones in crocodiles and alligators. In the modern animals, these openings house receptors that let them sense movement in the water.

Paleontologists Nizar Ibrahim, left, and David Martill examine
 a spine fragment of Spinosaurus found in southeastern Morocco.
 (Photo by Cristiano Dal Sasso )
 

Huge, slanted, interlocking teeth seem perfectly shaped to catch fish, and hook-like claws would have been ideal for catching hold of slippery prey under the water. Big, flat feet (perhaps even webbed) would have been well-suited to paddling water or stomping through mud, and some unusually dense limb bones (more like those seen in penguins than those found in other dinosaurs, the researchers report) would have allowed it to keep itself under the water, instead of floating.
The dinosaur's skeletal shape indicates that it would have been a strange sight to us on land. The Spinosaurus's center of gravity was pushed forward by its long neck, so it was almost certainly impossible for it to walk on two legs. In fact, the Spinosaurus's legs and pelvis are quite like those seen in early whales -- much better for paddling than for walking. Like whales, these dinosaurs probably evolved from land-dwelling ancestors to become semi-aquatic.

Skull reconstruction of Spinosaurus aegyptiacus showing discovered
 bones in blue. (Image by Davide Bonadonna, Ibrahim et al., Science/AAAS)
 

Scientists aren't quite sure how Spinosaurus moved when it left the water -- which it must have done, at the very least, to lay and nest eggs. Spinosaurus didn't have the kind of limbs that scientists would expect in a four-legged animal, but it also couldn't have balanced on its hind legs for very long.
"I think that we have to face the fact that the Jurassic Park folks have to go back to the drawing board on Spinosaurus," co-author and University of Chicago paleontologist Paul Sereno said in a teleconference held by Science on Wednesday. "It was not a balancing, two-legged animal on land. It would have been something very peculiar."
This isn't to say that Spinosaurus wouldn't have been an impressive sight on land. "It would have been a fearsome animal. There's no question about it, you would not want to meet this animal on land," Sereno said. "But it was not gallivanting across the landscape."
While paleontologists continue to puzzle over how the Spinosaurus managed to walk, you can visit a life-size skeletal replica of the creature at the National Geographic Museum in Washington. The exhibit will run Sept. 12th through April 12.

Were dinosaurs warm or cold blooded? Ancient eggshells could reveal the truth.

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By Rachel Feltman October 13

An artist’s rendering of oviraptorid theropods. (Doyle Trankina and Gerald Grellet-Tinner)

Were dinosaurs warm or cold blooded? New data suggests that the answer might be a simple "yes".
Back in the day, paleontologists assumed that dinosaurs were all lizard-like, and had the slow metabolisms to match — making them cold blooded, like alligators. These kinds of animals, more formally known as ectotherms, have to get most of their body heat from their environment. Endotherms, like humans and other mammals, are capable of producing most of the heat they need internally.
[Fossils might reveal the colors of ancient critters]
Now we know that many dinosaurs were actually bird ancestors. Birds are endothermic, and have super fast metabolisms.
So did some dinosaurs have bird-like metabolisms, and the hot blood to match? A study published Tuesday in Nature Communications claims to have found the answer in fossilized eggshells.
The basic findings line up with what most recent research in the area has concluded: Dinosaur metabolisms were all over the place.
"It's important to realize that there's actually a whole sliding scale of physiology," even in the modern animal kingdom, study author Robert Eagle of the University of California told The Post. Birds have metabolic rates that put humans to shame, he explained, making them arguably more "warm blooded" than we are. And then you have critters like sloths, that are on the slowest, coolest end of the warm blooded spectrum. "So the real question is where dinosaurs fell on that spectrum," he said.
[A crummy dinosaur fossil turns out to hold 75 million-year-old blood and proteins]
That's where Eagle's work comes in. He and his colleagues analyzed the chemical makeup of ancient eggshells, using a technique previously perfected on teeth to estimate the temperature of the body they formed in. By measuring the abundance of chemical bonds between two rare, heavy isotopes (carbon-13 and oxygen-18) in calcium carbonate minerals, scientists can estimate body temperature. A mineral that forms at colder temperatures will have more of these bonds than the same mineral formed at a higher temperature. In the case of an egg, scientists can use this ratio to estimate the temperature of the mother's body when she formed it. 

A large clutch of Titanosaur eggs. (Luis Chiappe)

After showing that this measurement worked in eggs from modern animals, Eagle and his colleagues tested fossilized eggs. Many showed signs of decay that would alter any conclusions about temperature, but they were able to analyze two species successfully — and found signs of a range of metabolic rates.
One was a long-necked titanosaur sauropod, and it indicated a maternal body temperature of about 100 degrees Fahrenheit, comparable to large mammals today. Another species — a T. rex-like oviraptorid — indicated a cooler 90-degree body temperature, which is lower than most modern mammals.
But chances are that both of them were at least somewhat endothermic, Eagle explained. Analysis of the soil around the oviraptorid eggs indicates that the air temperature may have been lower than their body temperature.
"We can't take just body temperature and jump to the conclusion that they weren't cold blooded," Eagle said, "but combined with other data, it's consistent with them having some kind of intermediary metabolism. This suggests that maybe they were warm blooded, but hadn't developed the high level of temperature regulation seen in mammals and birds today. They were kind of part way to evolving endothermy."
Since oviraptorids like this one were close relatives to the earliest birds, Eagle hopes that studying the evolutionary lineage more closely will reveal when and how metabolisms sped up so drastically.
"There's just a massive spectrum of different questions we can ask now," he said.

Scientists Have Drafted a Complete Tree of Life

Maddie Stone9/19/15 3:00pm



Humans, bacteria, daffodils: We’re a diverse bunch on the surface, but trace each and every Earthling back far enough, and you’ll arrive at a common ancestor. For the first time, scientists have built a comprehensive tree of life that binds us all together.

A draft of the One Tree, published Friday in the Proceedings of the National Academies of Sciences, includes the roughly 2.3 million named species of animals, plants, fungi and microbes. It shows how all of the major branches relate to one another and traces each individual group back to its shared beginnings in a prebiotic soup 3.5 billion years ago.

“This is the first real attempt to connect the dots and put it all together,” said principal investigator Karen Cranston of Duke University in a statement. “Think of it as Version 1.0.”




This family tree of Earth’s lifeforms is considered a first draft of the 3.5-billion-year history of how life evolved and diverged. Image Credit: opentreeoflife.org

To build the tree of all life, researchers compiled thousands of smaller trees that had already been published online. One of the big challenges was simply accounting for the different taxonomic names, spellings and misspellings that crop up across scientific papers. For instance, in a strange fluke of taxonomy that I can only hope has inspired some fantastically weird artwork, spiny anteaters once shared their scientific name with moray eels.

The tree will continue to receive updates over time, of course — scientists are still discovering new species of plants, animals and fungi every year, and with our growing arsenal of genomic sequencing tools, we’re finally beginning to unlock the vast diversity of the microbial world. The team behind the tree is developing software tools that’ll enable researchers to log in and revise things as new data is collected.

In the meanwhile, the biology nerds in the room can start exploring all of this juicy data right now. The tree, along with the raw data and source code that built it, is available for free online at https://tree.opentreeoflife.org.

[Read the full scientific paper at PNAS h/t phys.org]