In April authorities were called to check out a report of possible human remains near a sunken boat in waters about 200 yards off Key West. The remains looked like a human torso sitting in a captain's chair.

Monroe County Sheriff's Office detectives arrived to find Florida Fish and Wildlife Conservation Commission officers inspecting the remains. The verdict: It was a plastic, novelty skeleton someone left out in the water.

The case was similar to calls a few years ago when a mannequin, mistaken for human remains, was found in an abandoned boat off Sugarloaf Key. Again, detectives were called out, said Sheriff's Office spokeswoman Becky Herrin.

The finds usually end up in the pages of newspapers and online as tongue-in-cheek goofs, but Florida Keys National Marine Sanctuary (FKNMS) officials said Thursday there is a larger issue at play: It is seeing an increase in the number of folding chairs, lawn ornaments, bicycles and other items left in environmentally sensitive waters ostensibly for funny underwater photos.

"It might seem innocuous to put a lawn chair or garden gnome out there," said FKNMS spokeswoman Karrie Carnes. "The majority of time most people innocently don't realize that this harms the sea floor."

Sanctuary officials are getting the word out now as full moons during August and September are typically the times that coral are spawning out on the reef, marking a particularly sensitive time.

The advent of digital cameras, cell phone photography and social media have given rise to many more instances of trash being found in the sanctuary, which runs 2,900 square nautical miles on both sides of the Keys from Key Largo to the Dry Tortugas.

Since 1997, the seafloor has been protected by sanctuary regulations that prohibit people from leaving non-approved material behind, Carnes said. Exceptions include anchoring in waters greater than 40 feet deep and lobster and stone crab traps.

"We see all sorts of things out there," said Sean Morton, sanctuary superintendent. "Golf balls, plastic pink flamingoes, candy, you name it. The problem is that as more and more of this proliferates it sends the message that it's OK and not harmful and we're asking seasoned divers to work with us."

Typically, first-time violators are given a warning, but serious violations could lead to fines between $100 to $300 for the violations sanctuary divers most often come across. Commercial-type violations, such as those in which large amounts of debris are dumped or the sea floor is drilled, dredged or otherwise damaged, could lead to penalties in the tens of thousands of dollars, Morton said.

Large events like the Underwater Easter Egg hunt in Key Largo and the Underwater Music Festival at Looe Key are permitted events that take place with the blessing of federal officials who also dive and ensure that the areas affected are properly cleaned of debris afterward, Carnes said.

Permit applications for research and education activities are reviewed on a first-come, first-served basis. On average, processing time for permits is 30 days, but may be longer for complicated requests or requests that include the collection of sensitive or prohibited organisms like coral species.

Though an area may look barren or "just like a rock," it may be teeming with life, Carnes said.

"We want help from everyone in reminding those who may not know that the reef is a living organism, not a jungle gym," Carnes said.

For additional information on sanctuary permits, visit http://floridakeys.noaa.gov/permits/welcome.html.

alinhardt@keysnews.com