An article in Scientific American about using subway cars for artificial reefs

One question that was largely overlooked in the entire controversy was whether artificial reefs should be created at all. Many fishing groups supported the reef-building efforts, arguing that more reefs and therefore more habitat would lead to more reef fish, but that may not be the case. "It's obviously beneficial to the person who has a boat that makes money renting space on the boat to catch fish. And it's of benefit to the person that has a private boat and wants to catch fish," Bennett says. "The question is whether it's good for the fish, and I don't think we know the answer."

Read the entire article here:
http://www.scientificamerican.com/article.cfm?id=the-submerged-subway-reef