Marine scientists are to use baited underwater video cameras to assess blue cod stocks in Fiordland.
Two popular recreational blue cod fishing areas at Milford and Doubtful Sounds have been closed by the Minister of Fisheries since 2005.
The National Institute of Water & Atmospheric Research says the cameras will be baited with paua guts and deployed to depths of up to 80 metres.
Dr Trevor Willis says this method has several advantages over the standard hook, tag and release programmes.
He says the fish are not stressed from being removed from the water and scientists are able to get more accurate assessments by using cameras.
He says the method has successfully been used elsewhere to assess snapper stocks.