Friday Morning: Counting Fish on the Fly, and Dancing Icebergs

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Sea floor photo with two hidden skates
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Can you find both of the skates in this picture? HabCam did, and it counted the scallops and measured the sand grains, too. (Richard Taylor, courtesy Scott Gallager, WHOI)

Two icebergs pirouette off Palmer Station
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A snapshot from Gallager's remarkable video of two icebergs pirouetting just off Palmer Station, Antarctica. Watch the full clip at the PRIMO website (click on Photos). (Scott Gallager, WHOI)

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From Oceanus magazine, 1996

A smart camera system can count scallops and see hidden flounder

Part of the fun of a fishing trip is never knowing exactly what is swimming around beneath you. But that mystery is a major obstacle when it comes to keeping track of fish populations.

Fishery managers might be interested in a new device called HabCam that takes razor-sharp images of the sea floor and then automatically classifies fish habitat and counts bottom-dwelling fish - even the nearly invisible skates and flounders. The device was developed over six years by WHOI scientist Scott Gallager and a team of WHOI engineers and Cape Cod scallop fishermen.

The HabCam is a high-resolution video camera housed in a footlocker-sized box and equipped with bright lights and several water sensors. A small fishing vessel tows the device at about three meters above the sea floor (roughly the height of a basketball net), traveling at three to five knots. A four-hour cruise can traverse around 25 km (15 miles), recording 31,000 images and 50 gigabytes of data.

Onboard, scientists and fishermen can watch the sea floor go by as a fiberoptic cable brings images back from the camera. Sophisticated analysis programs detect the size of individual sand grains and find the boundaries around larger objects, like scallops and fish. The program foils even the best camouflage by picking up on changes in texture as well as color.

HabCam’s imaging system is similar to the one on SeaBED, a robotic vehicle that takes pictures of the deep-sea floor. Whereas pre-programmed robotic surveys are good for mapping projects, Gallager said, watching in real time through HabCam lets surveyors double back to investigate interesting areas.

Conventional monitoring of many bottom fish, including scallops, is usually done by dredging swaths of sea bottom and examining the catch. HabCam can identify and count fish without disturbing them and even measure their sizes, helping fishery managers judge when they should close or re-open precise portions of the ocean.

The Ocean Sites abstract abbreviated the list of authors for this poster. The full list is: S. Gallager, S. Tiwari, J. Howland, A. Girard, L. Abrams, H. Singh, R. Taylor, N. Vine, R. Smolowitz, P. Rago and D. Hart.

24-hour Antarctica on your desktop

HabCam isn’t even Gallager’s main project. That title belongs to PRIMO, the first cabled observatory in Antarctica, scheduled for installation this June.

Cabled observatories are suites of instruments placed several kilometers out to sea but connected to the mainland with long power and data cables (like Martha's Vineyard Coastal Observatory). PRIMO will be connected to the longtime research outpost at Palmer Station, Antarctica.

The observatory will measure “pretty much anything you can make a sensor for,” according to Gallager’s colleague Vernon Asper of the University of Southern Mississippi. Asper is most excited about the eight megapixel video and still cameras, which will be on the lookout for passing fish, penguins, and leopard seals.

The formidable Antarctic weather necessitated some careful design. Gallager mapped the surrounding seafloor in detail before choosing where to place PRIMO - in a narrow channel 130 meters (430 feet) deep, where rock walls protect the instruments from scraping icebergs. In shallow water near shore, the cables will be protected by iron cases bolted to the rock.

With data flowing to Palmer Station and then relayed by satellite back to the U.S., Gallager and Asper will be able to watch the undersea Antarctic through summer and winter. (Gallager already has a full-time webcam installed on land at Palmer Station. It has produced some beautiful time-lapse video of pirouetting icebergs).

All this for only about 2 kilowatts of power. That’s nothing, Asper said - for example, it’s way less power than Palmer Station uses just to heat the hot tub (click, then scroll down).


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Last updated February 24, 2006
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