More on this please..........what is a "good location" how do they decide that?
Near another coral reef?
Les is calling out my inner science nerd here, so be warned.
There are a number of different factors that have to be considered before just dropping something down on the ocean floor expecting it to become a reef or useful structure.
The 1st thing is the depth of the water. If you're looking to create a reef for hard corals to attach themselves to... you can't go too deep. Let's just say 100 feet or less for hard corals. Hard corals are the ones that we hear about dying from bleaching these days. Sunlight is very important for them to be able to grow... the deeper you get... the less light comes down.
Soft corals form on deeper structures. They don't require as much light as the hard ones.
Another important factor is the current. Many people have no idea that there is a literal river running along the east coast of Florida known as the Gulf Stream... and it is powerful and strong. The current created in this never stops, but it does fluctuate a small distance east and west almost daily. Drop something in the Gulf Stream off Florida and it might end up off the North Carolina coast in a few days. It flows north.
The daily tide rythm also has to be considered. The high tide depth may be perfect... but during low tide your structure may be above water during certain moon cycles. Plus... the orientation of the structure needs to allow for the current to flow over it in a way that promotes growth for coral and places for fish to escape the currents. Think about it this way... have the nose of a sunken ship pointed into the current (old boats and ships are used all the time)... if the current is blasting against the side of the ship it will cause the thing to fall over and probably move completely away from where you wanted it to be placed. Ocean currents are super strong.
The material you're using is also a factor. I mentioned old ships... but many times old concrete bridges and culverts are used along with big chunks of used concrete. The old oil rig towers are great because of their shape and openness. They're perfect structures for fish and coral. Old airplanes are sometimes used as well.
Still another thing to consider is the boat traffic or possible shipping lanes. You don't want to create a possible hazard for ships and boats.
Temperatures of the water in the location also have to be considered.
There's other shit too... but the bottom line is... you can't just toss something overboard and expect it to turn into a useful structure for for marine life. It's complicated.
