Science Fiction Dictionary
A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

 

Bio Acoustic Fish Fence May Protect Great Lakes

A bio acoustic fish fence (BAFF) is being tested on a tributary about 200 miles from Chicago by ecologist Gregg Sass. The BAFF is basically an underwater sonic fence; a barrier created by outputting sounds into a wall of bubbles.

The intent is to stop invasive Asian carp species from swimming up the Illinois river and reaching the Great Lakes, which already have enough problems.

It uses an air bubble curtain to contain a sound signal which is generated pneumatically. Effectively, this creates a "wall of sound" (an evanescent sound field) field that can be used to guide fish around river structures by deflection into fish passes.

Physically, the BAFF comprises a pneumatic sound transducer coupled to a bubble-sheet generator, causing sound wave to propagate within the rising curtain of bubbles. The sound is contained within the bubble curtain as a result of refraction, since the velocity of sound in a bubble-water mixture differs from that in either water or air alone.


(An effervescent wall for fish)

1. Inside a shed on the riverbank, a signal generator emits eight chirps at varying intervals and varying frequencies up to 2,000 Hz. Two 400-watt amplifiers pump up the beeps to carp-deafening levels.
2. A compressor pushes a continuous stream of air through a rubber pipe riddled with small holes. The pipe, housed in an open steel chassis, runs across the bottom of the riverbed.
3. The pipe releases a sheet of bubbles illuminated by strobe lights flashing 200 to 400 times per minute. Alongside the pipe, 16 hundred-watt sound projectors shoot the chirping sounds into the fizz, where the noise is concentrated.
4. Native fish like trout and salmon can't hear frequencies above 400 Hz and swim through the bubbles unfazed. Carp, which perceive sound as high as 2,000 Hz, hit the piercing noise and turn back.

The first place I read about this idea was in Roger Zelazny's 1976 novel My Name is Legion; he refers to sonic curtains that can be used to keep sharks out of selected areas in underwater parks. Amusingly, dolphins can be taught to use it, and in turn teach other dolphins.

From Wired via Neatorama. See also this article on the fish fence.

Scroll down for more stories in the same category. (Story submitted 8/16/2009)

Follow this kind of news @Technovelgy.

| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |

Would you like to contribute a story tip? It's easy:
Get the URL of the story, and the related sf author, and add it here.

Comment/Join discussion ( 0 )

Related News Stories - (" Engineering ")

Climate Engineering In California Could Make Europe's Heat Waves Worse
'Pina2bo would have to operate full blast for many years to put as much SO2 into the stratosphere as its namesake had done in a few minutes.' - Neal Stephenson, 2021.

Textiles That Harvest Energy And Store It
'The clothes and jewelery drew their tiny power requirements from her movements.' - Alastair Reynolds, 2005.

Coin-Sized Nuclear Battery Good For 100 Years
'...power pack the size of a pea.' - Alfred Bester, 1956.

The FLUTE Project - A Huge Liquid Mirror In Space
'It's area, and its consequent light-gathering capacity, was many times greater than any rigid mirror...' - Raymond Z. Gallun, 1934.

 

Google
  Web TechNovelgy.com   

Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.

 

 

 

 

Science Fiction Timeline
1600-1899
1900-1939
1940's   1950's
1960's   1970's
1980's   1990's
2000's   2010's

Current News

Shanghai Guidelines For Humanoid Robots
'Now, look, let's start with the three fundamental Rules of Robotics...'

Desktop TARS Robot From Interstellar
What's YOUR sarcasm setting?

Robots Can Now Have Smiling Faces With Human Skin
'I am a cybernetic organism...'

Virtual Rat Predicts Actual Rat Neural Activity
'..the synthetic intellects at the Place of Knowledge had far outstripped the minds of men.'

GoSun EV Solar Charger Drapes Onto Your Car
'...six square yards of sunpower screens.'

Rizon 4 Ironing Robot
'But after washing and drying clothes had to be smooth - free from fine lines and wrinkles ...'

Cognify - A Prison Of The Mind We've Seen Before In SF
'So I serve a hundred years in one day...'

Robot With Human Brain Organoid - 'A Thrilling Story Of Mechanistic Progress'
'A human brain snugly encased in a transparent skull-shaped receptacle.'

Goodness Gracious Me! Google Tries Face Recognition Security
'The actuating mechanism that should have operated by the imprint of her image on the telephoto cell...'

With Mycotecture, We'll Just Grow The Space Habitats We Need
'The only real cost was in the plastic balloon that guided the growth of the coral and enclosed the coral's special air-borne food.'

Can A Swarm Of Deadly Drones Take Out An Aircraft Carrier?
'The border was defended by... a swarm of quasi-independent aerostats.'

WiFi and AI Team Up To See Through Walls
'The pitiless M rays pierced Earth and steel and densest concrete as if they were so much transparent glass...'

Climate Engineering In California Could Make Europe's Heat Waves Worse
'Pina2bo would have to operate full blast for many years to put as much SO2 into the stratosphere as its namesake had done in a few minutes.'

Optimus Robot Will Be A Good Nanny, Says Musk
'Nanny is different,' Tom Fields murmured... 'she's not like a machine. She's like a person.'

ESA To Build Moon Bases Brick By Printed LEGO Brick
'We made a crude , small cell and were delighted - and, I admit, somewhat surprised - to find it worked.'

Does The Shortage Of Human Inputs Limit AI Development?
'...we've promised him a generous pension from the royalties.'

More SF in the News Stories

More Beyond Technovelgy science news stories

Home | Glossary | Invention Timeline | Category | New | Contact Us | FAQ | Advertise |
Technovelgy.com - where science meets fiction™

Copyright© Technovelgy LLC; all rights reserved.