An ocean-going drone is helping to spot illegal fishing in the world's largest, continuous marine reserve.
The UK established the 834,000-sq-km (322,000-sq-mile) zone around the Pitcairn Islands in the Pacific in 2015.
Data gathered by the drone will be beamed back to a satellite watch room to help prosecute unauthorised trawling.
The drones will patrol areas in the reserve designated as no-fishing zones.
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