Posts Tagged ‘Fish’

Identifying Canadian Freshwater Fish Through DNA Barcodes

June 19, 2008

New research by Canadian scientists, led by Nicolas Hubert at the Université Laval in Québec brings some good news for those interested in the conservation of a number of highly-endangered species of Canadian fish.

The use of DNA for automated species-level identification of earth biodiversity has recently moved from being an unreachable dream to a potential reality in the very near future. The potential of mitochondrial DNA in achieving this target has been successfully assessed for all of the Canadian freshwater fish communities and the approach bears some very exciting promise.

Click here for the full article.

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Great whites more brainy than ‘Jaws’ typecast

June 18, 2008

Depicting great white sharks lunging out of the water to devour seals doesn’t seem to argue against the species’ reputation as one of the ocean’s most bloodthirsty predators. But Smithsonian magazine does just that in a new story, using the sophisticated way in which great whites hunt to show how they ought to be known more for brains than jaws:

Despite this awesome display of predator power, [marine biologist Alison] Kock and other researchers claim that the shark has been defamed: Its reputation as a ruthless, mindless man-eater is undeserved. In the last decade, Kock and other shark experts have come to realize that sharks rarely hunt humans — and that the beasts are sociable and curious. “Unlike most fish,” Kock says, “white sharks are intelligent, highly inquisitive creatures.”

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Unravelling The Mystery Of The Kitty Litter Parasite In Marine Mammals

June 9, 2008

Researchers at California Polytechnic State University have discovered what may be a clue to the mystery of why marine mammals around the world are succumbing to a parasite that is typically only associated with cats. The key may just be the lowly anchovy, according to research presented today at the 108th General Meeting of the American Society for Microbiology in Boston.

Toxoplasma gondii is a protozoan parasite which causes toxoplasmosis, considered to be the third leading cause of death attributed to foodborne illness in the United States. While the Centers for Disease Control and Prevention estimates that over 20% of the U.S. population carries the parasite, the only known reservoir of the infectious form of the parasite (the oocyst) are cats.

Over the past decade, toxoplasma infection has appeared in a variety of sea mammals including beluga whales, dolphins, sea lions and seals. It has also become a major cause of death in sea otters living off the coast of California. It is estimated that approximately 17% of sea otter deaths can be attributed to toxoplasma. While many believe fresh water runoff contaminated with cat feces is to blame, there is no definitive science on the source of infection.

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Memory In Honeybees: What The Right And Left Antenna Tell The Left And Right Brain

June 8, 2008

It is widely known that the right and left hemispheres of the brain perform different tasks. Lesions to the left hemisphere typically bring impairments in language production and comprehension, while lesions to the right hemisphere give rise to deficits in the visual-spatial perception, such as the inability to recognize familiar faces.

In the last few years, we have become used to the idea that functional asymmetry between the left and right sides of the nervous system is not unique to humans: fishes, amphibians, birds and mammals have functional and anatomical asymmetries.

So, the idea that all vertebrate species, even non-human ones without any linguistic skills, have an asymmetric brain seems to be finally accepted. Now, this process of extension among species is going on and brain lateralization has been extended beyond the class Vertebrata. Insects, with their nervous system so different from that of vertebrates, are also “lateralized”, as shown in a paper published in PLoS ONE by Lesley J. Rogers of the Centre for Neuroscience and Animal Behaviour, University of New England (Australia), and Giorgio Vallortigara, of the Centre for Mind/Brain Sciences, University of Trento (Italy).

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Otters Reveal Their Identity

June 6, 2008

Researchers of the Helmholtz Center for Environmental Research have developed two new methods, in order to be able to better estimate the numbers of European Otters (Lutra lutra) and their effects on the fish farming industry. The researchers succeeded for the first time in gathering more accurate data on the otter population in the heath and pond region of the Oberlausitz Biosphere Reserve. Genetic analyses of the faeces could prove to be a promising approach when investigating otter populations, as researchers have written in the scientific journal Conservation Genetics. The new method does not only apply to otters, but also to all vertebrates.

The information can be used to ensure effective nature conservation. Accurate information on the size of the otter population makes it possible to calculate the quantity of fish eaten per pond and hence the damage incurred to the local fish farming industry. Consequently, appropriate damage compensation would improve the acceptance of otters among the local fish farming industry and thus the protection of this endangered species, as is required by national and international law. For population size estimates, the classical method of MRR (Mark Release Recapture) is enhanced by modern DNA analyses.

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Fish 380 Million Years Old Found With Unborn Embryo

June 6, 2008

In 2005, Museum Victoria’s expedition to the Gogo fossil sites in north Western Australia, led by Dr John Long, made a swag of spectacular fossil discoveries, including that of a complete fish, Gogonasus, showing unexpected features similar to early land animals.

Now the same team has made a new discovery: a remarkable 380-million-year-old fossil placoderm fish with intact embryo and mineralised umbilical cord.

The discovery, published in Nature, makes the fossil the world’s oldest known vertebrate mother. It also provides the earliest evidence of vertebrate sexual reproduction, wherein the males (which possessed clasping organs similar to modern sharks and rays) internally fertilised females.

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Male Seahorses Are Nature’s Mr. Mom, Researchers Say

May 27, 2008

Male seahorses are nature’s real-life Mr. Moms — they take fathering to a whole new level: Pregnancy.

Although it is common for male fish to play the dominant parenting role, male pregnancy is a complex process unique to the fish family Syngnathidae, which includes pipefish, seahorses and sea dragons. Texas A&M University evolutionary biology researcher Adam Jones and colleagues in his lab are studying the effects of male pregnancy on sex roles and sexual selection of mates and are trying to understand how the novel body structures necessary for male pregnancy evolved. By doing this, the researchers hope to gain a better understanding of the evolutionary mechanisms responsible for changes in the structure of organisms over time.

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Dramatic Impact Of Sea-Level Rise On Chesapeake Bay’s Coastal Habitats

May 23, 2008

A new report, Sea-Level Rise and Coastal Habitats of the Chesapeake Bay, shows in vivid detail the dramatic effects of sea-level rise on the largest estuary in the US, which sustains more than 3,600 species of plants, fish and animals including great blue herons and sea turtles.

If global warming continues unabated, projected rising sea levels will significantly reshape the region’s coastal landscape, threatening waterfowl hunting and recreational saltwater fishing in Virginia and Maryland, according to the report by the National Wildlife Federation.

Habitats at Risk

Coastal habitats in the Chesapeake Bay region, near Washington D.C., will be dramatically altered if sea levels rise globally about two feet by the end of the century, which is at the low end of what is predicted if global warming pollution remains unaddressed.

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Restoring Fish Populations Leads To Tough Choice For Great Lakes Gulls

May 22, 2008

You might think that stocking the Great Lakes with things like trout and salmon would be good for the herring gull. The birds often eat from the water, so it would be natural to assume that more fish would mean better dining. But a new report published in the April journal of Ecology by the Ecological Society of America says that the addition of species such as exotic salmon and trout to the area has not been good for the birds, demonstrating that fishery management actions can sometimes have very unexpected outcomes.

Craig Hebert (National Wildlife Research Center in Ottawa, Canada) and his team analyzed 25 years of data on the gulls and found that throughout the Great Lakes region, the birds were in poor health in many areas. Tests of their fatty acids showed an increase in the type of transfat that mostly comes from food produced by humans.

“It seems that the birds are being forced to make a dietary shift from fish to terrestrial food, including garbage,” says Hebert.

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“Reverse Evolution” Discovered in Seattle Fish

May 22, 2008

When a historic cleanup helped clear the waters of a polluted lake near Seattle, a population of tiny, spiny fish called sticklebacks may have “evolved in reverse” to survive.

In the 1950s, Lake Washington, an inland lake that parallels Washington State‘s Pacific Coast, took on 20 million gallons (76 million liters) of phosphorous-laden sewage a day (see Washington State map).

By the 1960s it had become a 300,000-acre (121,400-hectare) cesspool.

Then an unprecedented U.S.-$140-million cleanup in the mid-1960s transformed the lake into the pristine boaters’ paradise that it is today.

But the lake’s recovery put at least one species in a pickle: the three-spine stickleback.

The small fish, formerly hidden in the murky depths, found itself swimming in plain view of predators like cutthroat trout.

Researchers now think the threat of predators spurred the fish into rapid evolution toward an older version of itself, evolutionarily speaking.

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Meetings with a Mutt? More Pets Share Office Space

May 21, 2008

Dogs and cats and fish, oh my! More than 63 percent of American households own a pet today, which equates to 71.1 million homes and a whopping 382.2 million pets, according to a recent American Pet Products Manufacturers Association survey of pet owners. So are Fluffy and Fido just hanging out at home, or are they going to work with their human companions?

Pets, it seems, are showing up in the workplace more than ever, with 30 percent of employers allowing workers to bring pets to the office, according to a recent consumer survey commissioned by The HON company, a leading designer and manufacturer of office furniture. Of those who actually bring their pets to work, the majority of Americans bring dogs (24 percent), followed by fish (12 percent) and cats (8 percent).

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Coral Sea species facing extinction: WWF

May 21, 2008

The Coral Sea must be declared a protected zone to save sharks and some other marine species from rapid extinction, says the conservation group WWF.

The organisation says two separate reports show many Coral Sea marine species are isolated and vulnerable to overfishing.

It is home to populations of whitetip and grey reef sharks, nautilus, maori wrasse and other fish species, which WWF says have been decimated in similar habitats around the world.

“For this reason alone, we are renewing our calls to the federal government to declare the entire Coral Sea a marine protected area,” WWF spokeswoman Gilly Llewellyn said.

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Tiny fish cleans abandoned pools at foreclosed houses

May 12, 2008

While lawmakers in Washington struggle to solve the nation’s foreclosure crisis, officials here are using a small fish to clean up some of the mess.

The Gambusia affinis is commonly known as the “mosquito fish” because of its healthy appetite for the larvae of the irritating and disease-spreading insects. Lately, the fish is being pressed into service in California, Arizona, Florida and other areas struggling with a soaring number of foreclosures.

The problem: swimming pools of abandoned homes have turned into mosquito breeding grounds.

“They are real heroes,” says Josefa Cabada, a technician at the Contra Costa Mosquito & Vector Control District, a government agency. “I’ve never seen a mosquito in a pool with mosquito fish.”

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Asia’s love of ‘living art’ koi fish growing

May 10, 2008

Koi, an ornamental fish which enthusiasts liken to a moving work of art, are gaining popularity across Asia thanks to changing lifestyles and increasingly sophisticated tastes, experts say.

Asian fish connoisseurs treasure koi — domesticated varieties of the common carp — as Europeans would a painting by the Spanish artist Pablo Picasso, they say.

“I look at a Picasso and I say it’s a child’s painting… but people will pay hundreds of thousands or even millions of dollars for it. For Asians, koi is like living art… it’s like poetry in motion,” said Richard Tan, chairman of the committee that organised the First Asia Cup Koi Show in Singapore this month.

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Giant Stingrays Found Near Thai City

May 7, 2008

Recreational fishers and biologist Zeb Hogan (wearing cap) hold a live, 14-foot-long (4.3-meter-long) giant freshwater stingray the fishers caught in the Bang Pakong River in Chachoengsao, Thailand, on March 31, 2008.

After weeks of combing remote Southeast Asian rivers for giant freshwater stingrays—possibly the largest freshwater fish in the world—Hogan finally found the creature near a Thai city. To his surprise, she gave birth soon after capture. (Read full story.)

There are accounts of freshwater stingrays growing as large as 1,000 pounds (450 kilograms), which could make them the largest freshwater fish in the world, Hogan said.

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Fish Can Have These Luxury Subway Condos for a Song

May 3, 2008

New York City Transit released the first glimpse of old subway cars that act as active marine reefs this week.

[…] New York subway cars are considered the luxury condominiums for fish. States have experimented with other types of artificial reef materials, including abandoned automobiles, tanks, refrigerators, shopping carts and washing machines.

But subway cars are ideal because they are roomy enough to invite certain fish, too heavy to shift easily in storms and durable enough to avoid throwing off debris for decades.

Best of all, they are free. Both to the fish and to the states that want them.

Click here for the full article.

Legless Lizard And Tiny Woodpecker Among New Species Discovered In Brazil

April 30, 2008

Researchers discovered a legless lizard and a tiny woodpecker along with 12 other suspected new species in Brazil’s Cerrado, one of the world’s 34 biodiversity conservation hotspots.

The Cerrado’s wooded grassland once covered an area half the size of Europe, but is now being converted to cropland and ranchland at twice the rate of the neighboring Amazon rainforest, resulting in the loss of native vegetation and unique species.

An expedition comprising scientists from Conservation International (CI) and Brazilian universities found 14 species believed new to science — eight fish, three reptiles, one amphibian, one mammal, and one bird — in and around the Serra Geral do Tocantins Ecological Station, a 716,000-hectare (1,769,274-acre) protected area that is the Cerrado’s second largest.

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Why Are Kids So Crazy About Animals?

April 30, 2008

Yeah, zoos are fun. So are cartoons. And I certainly see the appeal of a teddy bear.

But why are kids so over-the-top crazy about animals? I am especially struck by the fact that some of the most popular cartoon and children’s-book animals are among the least appealing animals in real life. Mice, for instance. And pigs and rats and bears and fish.

Here’s what I read the other day in the class newsletter my daughter brought home from kindergarten:

Post Office Money Update: After a vote among all four K classes about how to spend this money, “Animals” received the most votes. (Other choices were Kids, Grown-Ups, and the Earth.) Please let us know if you are aware of any reputable organizations which are devoted to animals.

I wouldn’t expect kids to want to give any of their money to grown-ups. And while kids may be helping to drive awareness of climate change, “the Earth” is a pretty amorphous target.

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Rampant overfishing endangers Baltic fish stocks

April 30, 2008

A storm is brewing, which means that coastal fisherman Zbignew Struck, 46, is taking in his salmon nets in the Bay of Puck in Poland.
“The storm could tangle the nets”, he says from the cabin of his boat.
There is another reason for the haste: Struck has cast his nets into the sea without permission.
“I am afraid that the fishing inspectors will show up. They watch us from the air and at sea, and wait for us in the harbours”, says the fisherman, who shakes his head at the thought of a hefty fine.

The inspectors have been cracking down on coastal and open-sea fishing, as Poland has been put under pressure by the European Union to do something about rampant fish poaching.  According to an assessment made last year, Poland had been in violation of cod quotas. As punishment, a ban on cod fishing in the Baltic Sea was imposed on Poland for the second half of the year.  The most defiant flouted the ban. Now the fishing routine is nearly back to normal, and illegal fishing continues unabated.

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Giant squid may decimate British Columbia fish population, scientists fear

April 30, 2008

Nightmarish packs of rapacious giant devil squid are hunting off the B.C. coast — and as their numbers increase, scientists are worrying about an attack on fish stocks.

Humboldt squid, called diablos rojos or red devils in Mexico, have been known to attack scuba divers, and were once a rarity in B.C. waters. But a changing ocean environment has brought them northward, and they may now be permanently establishing themselves off the B.C. coast.

Along the squid’s tentacles are about 2,000 suction cups, each circled with dozens of sharp teeth, to drag food to the razor-sharp beak with which it eats.

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