“For 15 years, officials, environmentalists, fishermen and boaters have struggledto put together a plan to protect one of South Florida’s jewels — a national park, almost entirely underwater, where a part of the largest reef tract in the United States lures throngs of divers and anglers who fish its once-abundant grouperand snapper.... The fish have come under pressure not only from South Florida’s booming population but also because fast boats, GPS devices and other high- powered gear make finding and catching fish much easier than it was a coupleof decades back.... Closing the 10,522 acres to fishing — a section of the park that the federal government controls alone — is one of several options on the table, Mr. Carlstrom [Brian Carlstrom, the park’s superintendent] said. It has been shown, in some cases, to be an effective and quick way to replenish fish stocks, scientists said.... State officials bristle at the idea of a no-take reserve. They said the proposed section is one of the park’s most popular areas and covers about 30 percent of the reef tract. In their view, shutting down fishing should always be a last resort, and in this case it is not, they argued.