Tuesday, September 4, 2012

3-D 'Seahorse' cam tracks scallops, and sees a lot more

University of Delaware's research vessel, the Hugh R. Sharp, is one of the most advanced research ships in the United States.
The ship is outfitted with a full range of oceanographic equipment and instrumentation, including fiber optic wire.
Researchers are using that wire with an underwater video system to help NOAA survey scallop populations along the mid-Atlantic coast.

From HuffingtonPost

A new underwater explorer hit the seas this summer, armed with cameras, strobes and sonar and charged with being a protector of sorts to a half-billion dollar resource – the Atlantic scallop catch.

The stainless steel Seahorse, which gets its nickname from its s-shaped silhouette, traces its roots to a conversation a decade ago between a biologist and a fisherman who was seeking a better way to track the scallop population.

This summer, the instrument was towed over miles of seafloor, from Virginia to Cape Cod, taking millions of images and capturing details about marine life and the ocean floor that stretched beyond just the number of scallops.

The Seahorse revealed previously unseen ocean topography, predators stalking prey, and even the furrows left where fishing gear was pulled along the bottom.

Marine scientists just don't get this kind of look into the darkness on the ocean floor, said Dvora Hart, a National Oceanic and Atmospheric Administration mathematical biologist who leads the federal sea scallop assessment.
"We've been kind of blind before having this type of information," Hart said.

Eager for a low-impact way to tally scallops in the highly productive fishing waters off Cape Cod, local scallop fishers teamed with scientists and engineers at the Woods Hole Oceanographic Institution to design an innovative underwater camera called HabCam.
It acts as a satellite for the seafloor, trailing behind a fishing boat and snapping a continuous strip of pictures of the life at the ocean bottom.
HabCam surveys are also revealing a potential threat to the scallop fishery: an invasive marine invertebrate that is colonizing the very ground the scallops rely on.

The Seahorse is the fourth version of HabCam, an instrument originally created to better count scallops.
Former scalloper Richard Taylor had seen scallop industry's worst times around 1994, when the prime fishing areas were closed to protect depleted groundfish and scallop populations.

But by 1996, scientists discovered that areas that had been shut down to protect certain fish species were rich with scallops.
The industry has been thriving since the late 1990s, after regulators installed a plan to cut down fishing days and rotate fishing between different areas, to allow the stock to replenish in untouched regions.

Bob Keese is a scalloper operating out of Chatham, Massachusetts on Cape Cod.
This video showcases how Bob and his crew fish for scallops using a dredge, and shuck 600 pounds of scallop meat before they reach the docks at the end of the day.

Last year, the Atlantic sea scallop catch was worth $580 million in revenues, and the industry's best-known port of New Bedford has been the nation's top fishing revenue port for 11 years running.

Back around 2002, Taylor knew things were going well, but also knew how quickly they can go bad. He was particularly concerned about the inefficiency of the primary method for sampling scallops for use in population estimates – using a dredge to scoop them up.
A dredge misses varying percentages of the scallops it goes over, and Taylor worried the flawed information could eventually lead to the overfishing or underfishing that can drag down the resource and the fishermen.

Taylor talked with Woods Hole Oceanographic Institution biologist Scott Gallager, whom he had worked with on scallop issues.
"We need a better tool," he told Gallager.

They helped develop the Seahorse, along with the Deep Submergence Laboratory at Woods Hole.
It's an advance over previous versions of HabCam because it's equipped with strobes and two cameras, instead of one, enabling it to take 3-D pictures at a rate of 10 overlapping images per second.
It has side sonar to give high resolution images of the surrounding topography, and also equipment to measure variables such as temperature and water color.

The Seahorse is towed at about 7 mph, and moves 6 feet above the ocean floor.
The instrument, about 10 feet long and about 3 feet wide, is controlled by joystick by an operator in the towing vessel.

Since 2010, NOAA has spent $856,000 to develop, test and deploy the Seahorse.

Researchers have made a first pass through the 7 million images, studying 1 of every 200, and the data is being used in management decisions, Hart said.
A more detailed look is planned, she said.

The voluminous detail the Seahorse collects has application well beyond scallops and their habitat.
Hart notes, for instance, that the Seahorse captured pictures of the struggling yellowtail flounder, and may contribute to research in that fishery.
Its images of the effects of fishing gear can inform the hot, yet data-poor debate about whether fishing gear is wrecking the ocean bottom.

The Seahorse can't replace the dredge as a sampling tool. Scientists need to actually pull up scallops to get key information, such as by studying rings on the shells (much like tree rings) to learn about their growth rates.

And Taylor cautioned that new data from the Seahorse doesn't necessarily mean much when it comes to managing fisheries.
"I'm somewhat skeptical," he said.
"Just because you have better data, doesn't mean automatically that better decisions are made."

Scalloper Paul Rosonina runs a vessel that's towed the Seahorse and has been part of its development for years.
Scallop industry regulators can't do the right thing without good information, and that's what the Seahorse is about to him.

"You think I don't want my son to have a future?" he said.
"I want my grandson to have a future; I want my great grandson to have a future. I don't want this to die. ... I think it should be around forever."

Links :
  • RedOrbit : Juvenile scallops are abundant in Mid-Atlantic discovered by new survey of ocean floor

No comments:

Post a Comment