kottke.org posts about fish
In order to reproduce, salmon swim from the ocean up rivers until they find the spot they were born. But sometimes people build dams or other "artificial water constructions" that can disrupt salmon travel. A company called Whooshh Innovations has developed a tool to help with this problem: a pneumatic salmon cannon.
According to the folks at Whooshh, their transport system can handle 40-60 fish per minute, move the fish at 5-10 m/sec (11-22 mph), and transport fish 1000 feet into the air along a tube 2000 feet long. Here's a video showing how a similar fruit transportation system works:
A group of marine biologists that has been recently studying mesopelagic fish ("fish that live between 100 and 1000m below the surface") believes that 95% of fish biomass is unknown to humans. Marine dark matter. The problem lies with how fish have traditionally been counted and the enhanced visual and pressure senses of these fish.
He says most mesopelagic species tend to feed near the surface at night, and move to deeper layers in the daytime to avoid birds.
They have large eyes to see in the dim light, and also enhanced pressure-sensitivity.
"They are able to detect nets from at least five metres and avoid them," he says.
"Because the fish are very skilled at avoiding nets, every previous attempt to quantify them in terms of biomass that fishing nets have delivered are very low estimates.
"So instead of different nets what we used were acoustics... sonar and echo sounders."
A not-so-difficult prediction to make is that humans will find a way to catch these wary creatures, we'll eat most of them, and then we'll be back to where we are now: the world's oceans running low on fish. (via @daveg)
Asian carp were imported decades ago by catfish farmers to clean out the catfish pens. These carp escaped in the great catfish escape of 1983 (previous clause is more "truth" than "fact"), and don't have enough natural predators to prevent them from multiplying rapidly. The carp are spreading so quickly, President Obama recently allocated over $50 million to eradicate them. No one in the US really noticed this move. Chinese internet users, on the other hand, memed the story out in a variety of different ways.
To understand why Chinese netizens have taken such an interest in the story, it's absolutely essential to know that the most popular dinner-table fish in seafood-crazy China is carp, bar none...Add the fact that Chinese covet wild carp -- an expensive treat compared to cheaper, more common farmed carp -- and poetry ensues.
I like the use of the word 'poetry' to describe Internet explosions.
So says the first line of Paul Greenberg's story on fish oil. Which is weird for me because I had been wondering this very thing in my bathroom the other day while staring at my wife's bottle of omega-3 pills.
Nearly every fish a fish eater likes to eat eats menhaden. Bluefin tuna, striped bass, redfish and bluefish are just a few of the diners at the menhaden buffet. All of these fish are high in omega-3 fatty acids but are unable themselves to synthesize them. The omega-3s they have come from menhaden.
Menhaden are also top-notch algae eaters and, no surprise, overfished. (via djacobs)
Update: Bad Science questions whether fish oil is actually beneficial. (thx, phil)
The coelacanth, a 400 million year old prehistoric fish once thought to be extinct, has undergone a CT scan. Forty eggs were found inside of the large, frozen bodies of the two coelacanth tested, originally caught off the coast of Tanzania and then shipped to Japan for study.
The coelacanth young are thought to hatch inside of the mother and grow to 30cm before their live birth, when they swim outside of her body, looking identical to their parents, only tiny and cute. The discovery of the eggs could contribute to evidence that the ancient ocean dweller is the missing link between fish and amphibians:
Many scientists believe that the unique characteristics of the coelacanth represent an early step in the evolution of fish to terrestrial four-legged animals like amphibians. The most striking feature of this "living fossil" is its paired lobe fins that extend away from its body like legs and move in an alternating pattern, like a trotting horse.
As far as fish go, it's just a shade prettier than the sea wolf.
Researchers at Georgia Tech are working on a system to track the motion of fish in their tank in order to make music from their movements.
[Video removed because I couldn't figure out how to turn off the annoying autoplay. Go here to watch it.]
It works through a camera that uses recognition software that tracks objects based on their shape and color. The software then links each movement to different instruments that change in pitch and tempo as the fish patrol the tank. Fish that move toward the surface have a higher pitch. The faster they move, the faster the tempo.
The idea is to create audio aquariums for the blind. (via clusterflock)