We recently covered a study in which every single fish tested from U.S. streams was tainted with mercury. But that may be the least of our worries: The demand for fish will increase by 40 percent in the next two decades. As the world population hits 9 billion by 2050, the continued depletion of biodiversity and poor environmental conditions of the ocean could end up wiping fish completely off our menus. Not surprisingly though, aquaculture is picking up, and now more than 50 percent of the fish that ends up in our bellies was raised in coastal fish farms.
Fish raised in farms near the coastline are exposed to more pollution than wild fish, and therefore grow to be less nutritious. Ideally, we’d like our fish to roam around freely in the sea before we eat them.
Enter MIT’s Offshore Aquaculture Engineering Center, which is building robotic cages so fish can be farmed in the ocean away from the coastal waters. The Aquapod cage has 8-foot long propellers, which are controlled and powered from a generator in an attached boat. The cage, which strikingly resembles the Apple Store on New York’s Fifth Avenue, is built with triangular panels that are coated in steel nets. National Geographic reports:
“The idea of a cage towing a buoy, with the buoy in radio contact with the shore, is quite feasible,” [director Cliff Goudey said]. “It’s a little futuristic for today’s industry, but we could have a sensor on the cage which gives its heading and a GPS system to report its effective speed over the ground.”
Another group at Woods Hole Marine Biological Laboratory has a more open idea for a “cage”: They allow their fish to swim freely, but train them to return to their cage at the sound of a dinner bell. Granted, fish are hardly terriers: The bell worked for black sea bass for about a week, but when a school of bluefish came to dine on the bass, they refused to return to their cage despite the researchers’ offer of free food.
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Image: flickr/ Swamps
Seemingly straight out of a science-fiction movie, a fish with tubular eyes and a see-through head discovered off the coast of California.
Researchers in Monterey Bay have released pictures of the first Macropinna microstoma to be found with its “soft transparent dome” intact. The six-inch “barreleye” fish lives more than 2,000 feet below sea level and spends most of its time motionless, but has eyes that can rotate within its head, allowing it to see whatever is directly above it.
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Last month, we reported that female dolphins had learned to use sponges to catch their prey. And now, it turns out that not only do dolphins use tools, but they also have a recipe for calamari.
Australian researchers have observed a female bottlenose dolphin using her snout to prepare a meal of cuttlefish. But instead of just gobbling up the fish, the dolphin carefully extracted its bones before dining—a display of chef-like skills that is extraordinary among marine mammals.
The feast took place in South Australia’s Upper Spencer Gulf, where cuttlefish breed. The researchers had first filmed this amazing culinary-enabled dolphin off the coast of South Australia in 2003, where they saw her preparing four different cuttlefish. They were able to identify her in 2007 by her scars (apparently the circular scars on her head were unique enough to identify her four years later). They recorded her meals with a Sony HD Cam video camera, and later used the footage to analyze her foraging behavior. The results were finally published in PLoS One in January of this year.
In case you wanted to know, here’s her recipe for cuttlefish:
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• My, what a beautiful umbilicus you have! Survey says innies are hot, outies are not.
• Another week, another plan to exhume a dead astronomer. This time it’s Danish astronomer Tycho Brahe so historians can find out whether he was poisoned by a hired assassin.
• All in the family: Three completely different looking fish—known as tapetails, whalefish, and bignoses—turn out to be the young, female, and male of the same species.
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A newly-discovered species of catfish can use its fins for more than swimming. From the top side, Lithogenes wahari looks like any other catfish, except with some extra body armor. But flip it over and you’ll see a giant sucking mouth and a pair of fleshy pelvic fins, which it uses to grasp and shimmy up slippery rocks in fast-flowing rivers.
Scientists first laid eyes on the strange fish 20 years ago in Venezuela. But the only specimen they had was in such bad condition that it “looked like it had been run over by a truck,” recalls researcher Scott Schaefer. It took years before the team was able to locate more of the species, which they found in abundance in a tributary of the Orinoco river. Capturing L. wahari was easy: the researchers easily picked 84 specimens off of rocks.
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• Asexuals, unite! Just don’t start recruiting too many to your cause.
• Endangered oceans, rejoice: You have a secret weapon. And it’s fish poop.
• And it’s a good thing, since the best option we humans have come up with for saving all aquatic life is re-naming fish “sea kittens.”
• Facebook graduates from a civil litigation tool to a crime-fighting tool.
• This latest eco-trend actually makes some sense: cat hair clothing and accessories.
• Today in animal intelligence: Just how smart are bees, anyway?
The fish are acting funny because they’re on Prozac.
In the U.S., more than 200 million prescriptions for antidepressants are given out every year. A lot of the contents of those pills eventually end up in our water supply, either from patients’ excretions or from pills flushed down the toilet. Since water treatment plants aren’t designed to remove pharmaceuticals, we’re effectively medicating our streams and rivers.
Chemists have found that water downstream of water treatment plants holds a veritable medicine cabinet worth of antidepressants, including venlafaxine, bupropion (Wellbutrin), citalopram (Celexa), fluoxetine (Prozac) and sertraline (Zoloft).
The concentrations of antidepressants in the water—billionths of a gram per liter—aren’t enough to affect larger species, but they are enough to make small fish and fish babies feel woozy. Researcher Meghan McGee tested the effect of antidepressants on young minnows by exposing unhatched and newly-hatched minnows to levels of antidepressants commonly found downstream of water treatment plants. The drugged minnows appeared lethargic and took twice as long to react to stimulus, making them much more vulnerable to predators.
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You might think these scientists were potty training this whale shark based on their level of excitement when the giant fish (the world’s largest) finally had a bowel movement. The scientists, like some proud parents, even captured the moment on film. Researcher Mark Meekan described the rare poop, which he collected and stored in tiny vials, as “scientific gold” for the clues it would contain about the shark’s diet.
The researchers are studying the whale shark (Rhinsodon typus), a gentle cousin of the great white shark, to learn about the species’ mysterious feeding habits and migration patterns. DNA analysis of the poop confirmed that whale sharks, which can grow up to 12 meters long, sustain themselves on tiny red crab larvae. This also explains why they travel to Christmas Island, just south of Indonesia, where millions of red crabs spawn each year.
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Last week we revealed our Top Ten Science Halloween Costumes and asked you to send in your entries. By far the best was from Linda, who writes:
“Since my 3 year old daughter insisted that she had to be an anglerfish, I had to make her one. All the bioluminescence glows in the dark and the eyes glow as well. The light on her head blinks and bobs just like the real thing!!”
The female anglerfish is a natural trick-or-treater. It uses the bioluminescent esca dangling from its head like a fishing pole to lure other fish to its giant jaws. But just as the other fish think they’re in for a treat, the anglerfish reveals its trick and swallows them whole!
This is without a doubt the most adorable deep sea creature we’ve ever seen. Thanks Linda!
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Think you might have a problem with body odor? Here’s a dose of perspective: A 41-year-old woman in Australia has smelled like rotten fish all her life. The pervasive smell emanates from her sweat, breath, and urine, and cannot be washed off or covered up. After being “sniffed” by doctor after doctor, all of whom waved her off as a hypochondriac or even prescribed vaginal cauterization, she was finally diagnosed with trimethylaminuria, or “fish malodor syndrome.”
Though she can now put a name to her condition, the bad news is that there is no cure. Trimethylaminuria is a rare genetic disorder that prevents the body from producing an enzyme that breaks down trimethylamine, a fishy smelling substance found in foods like meat, eggs, peas, soy beans, and er, fish. Only about 600 cases of fish malodor syndrome are known in the world. Cutting out trimethylamine from the diet can help, but there is no effective treatment.
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