Underwater fence?

[G.I.B.]

I'm visiting some relatives in the Florida Key's and staying at the Key Largo Campground for a while. Anyhow, there is a pipe running from one end of the property to the other. Forced air is being pumped through the pipe causing the bubbles you see in the photos. This appears to be creating some sort of a 'fence' or 'dam' between the channel (left) and the two inlets to the boat slips (right).

I've not seen anything on the inside, so I'm assuming they are trying to keep something out.

Ideas? First hand knowledge?

 

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[Sandman]

It is said bubbles will deter Sharks............ I think if you look like food, you will be food...............

 

[tac512ltd]

They use it at a spot locally to keep manatees from a heavy use boat channel/dock area.

 

[Highwater]

There are two methods used to herd or corral fish, besides actually building a raceway or fence. One way is to use a bubble curtain, as Tac has posted, which in this case is to protect the Manatees from wandering into the boat channel.
The other method used is an electric wire with low voltage, which is the primary method used to herd salmon from streams and rivers into fish hatcheries. The wire is buried in the bottom of the stream at an angle to guide the fish into the hatchery.
Fish are very sensitive to even very low amounts of positive electrical current. One product that is being worked on and developed at this time is a device that divers can wear around shark infested areas. If shark get too close you merely push a button which puts an electric pulse in the water around you. The shark can't get out of the area fast enough. I am sure there will be a very good market for such a device.
I have often wondered about the effect of certain metal detectors when used in salt water and if they have any effect on fish? It would sure be worth a study to know.

 

[JoeSWFla]

I would love to see what kind of pipe they use to make that curtain wall,
as well as what size compressor/output.Great idea. As for the electrical
shark deterrent, I bought the newest model,but haven't had the time to
test it yet,for effectiveness,or for interference with my detector.HH Joe

 

[Highwater]

Joe,
I hadn't thought about the physics involved with the bubble curtain, but you sure have a point. It amazes me everyday what kind of ideas and inventions that man can come up with to solve a problem and to what extent he will go to in his endeavors. It has been like that all through history.
Please let us know how your apparatus for sharks works out and about the interference it might make with your detector. Is the thing on all the time, or just when you hit the button? HH Highwater

 

[JoeSWFla]

Greetings Highwater, The device(Shark Shield) stays on all the time,from
the time you enter to leaving.The only concern I have is that some claim
that it can attract them first,then repels at about 13 ft. radius .Has a long
antenna too-about 7',which trails behind you.Hope I can test it soon.
Bought it for the low vis. situation on this coast.I don't think it is
absolutely necessary,but certain areas have a lot of traffic,if you know
what I mean. As for the bubble curtain,I had an idea for that many
years ago ,but never pursued it.Now that I've seen it-has potential.
HH Joe

 

[G.I.B.]

I talked to a local fishing guide who has been fishing the Key Largo area for the last 20 years, and showed him the photo.

He told me that the 'air dam' is there to keep seaweed out. The bubbles put up a fence and as the tides and currents drag seaweed around, it stays out of the little canals. The seaweed, without the bubble fence, would collect in the canals, rot, and then stink really bad. This is the solution to that problem.

The water I saw in the canals inside the 'fence' was clear. No seaweed, no sharks, no manatees. It could be serving multiple functions.