In an effort to save the world's oceans from overfishing, many countries now require commercial fishing vessels to bring along an observer, who checks that the crew aren't exceeding their catch limits. That observer takes up cabin space on the boat, however, plus they require a salary, and probably aren't made to feel particularly welcome by the crew members. This month, however, a Spanish purse seiner became the world's first tropical tuna-fishing vessel to try out something different - an electronic monitoring system. Designed by Archipelago Marine Research, the EM Observe system is already in regular use in the company's home province of British Columbia, Canada.

EM Observe is able to detect fishing activity via multiple sensors placed around the vessel, such as hydraulic and drum rotation sensors, that are triggered when the net is being hauled in. Video cameras then record the type, size and amount of fish that are being captured, while a GPS registers the location and time of each catch.

All that information is stored on an onboard computer, which transmits the data by satellite once an hour. When the boat next returns to port, its hard drive can be removed, so fisheries personnel can have all the data in one place for review. In order to help make sense of the reams of data that may be on that drive, the company's EM Interpret software organizes everything into a single timeline display representing the entire fishing trip.

Along with the current trial run in Spain, EM Observe has additionally been tested on a trawler fishing for whiting in Oregon, and on two halibut vessels in Alaska. The system is also now in continuous use on all of British Columbia's commercial hook-and-line/trap groundfish fishing vessels, of which there are approximately 200.

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