Wanted: Ocean Recorder, with Batteries Dead or Alive

Aug 21, 2013

A WANTED! poster in search of the missing hydrophone.
Credit Courtesy of Dr. Aran Mooney

Researchers at the Woods Hole Oceanographic Institution are concerned by the mysterious disappearance of an underwater microphone, last seen on Horseshoe Shoal in Nantucket Sound.

“So the recorder is basically this long PVC tube about two-and-a-half feet long and about five inches in diameter,” said Dr. Aran Mooney, a biologist at WHOI. “It’s got a little brown hydrophone on the tip of it -- a Hydrophone is essentially an underwater microphone that sticks out on basically four inches of this very soft, flexible pipe, flexible cable. And so it just looks like a very odd looking PVC tube.”

Mooney is the researcher who put these recorders in the waters around Cape Cod as part of a research project designed to monitor ocean noise.

“The project that we’re working on here is trying to understand the baseline environment of Nantucket Sound and Vineyard Sound,” he said.

“We want to know the environment before any major development out there," he said. "Specifically, what we’re working on is changes in the environment before Cape Wind or a wind farm development on Horseshoe shoals. So how we’re doing that, we’re basically studying the sounds in the sea out there. So we’re listening to fish sounds and dolphin sounds and seal sounds and people’s boat sounds and we’re counting the abundances or how often the fish are making sounds out there or seeing how often boats go by.”

The recorders are left at sea for three to four months at a time. Then, they’re taken back onshore, where researchers listen and analyze the underwater sounds the microphones have recorded.

Everything was going according to plan, Mooney said, until they got a call from the harbormaster in Nantucket.

“In late June we had one of our recorders seem to go missing,” Mooney said. “We got a call from the Nantucket Harbormaster’s office that one of the recorders was on their dock. So it sounds like someone had kind of maybe accidentally brought it up, and the recorders had stickers and writing on them that say 'Woods Hole Oceanographic Institution,' and our phone number and so they dropped it off at the dock, and the Harbormaster kind of gave us a ring.

“We asked him to FedEx it out, or we could go out and pick it up, and they tried to FedEx it, but FedEx didn’t take it. And it seems like by the time they got around to letting us know that FedEx didn’t take it, it had been removed from the back of their truck. So recorder’s missing probably somewhere in Nantucket.”

Mooney said the sounds those hydrophones recorded are extremely important scientific data, particularly in advance of the Cape Wind project, which would install 130 wind turbines in the sound sometime within the next two years.

“So Cape Wind is going to be the first (offshore wind project) to go in," he said, "and it’s a really important wind farm, and it’s also really important as we construct future wind farms to understand if they may or may not change the local environment, and this set of data really gets us at that point. So it’s really crucial that we get it back.”

The recovery of the recorder is so important, in fact, that the WHOI is offering a reward to whoever finds it.

“There is a yet-to-be-determined reward that we can offer for getting that recorder back,” he said. “We don’t even really need the anchor or the chain or the floats that are attached, but the recorder -- the great PVC device with the underwater microphone attached -- is really the important thing to us and sort of the little data that’s inside it.”

If you have seen the hydrophon or have an idea where it may be, Mooney can be reached at 508.289.3714.