There is concern about kai moana stocks in Auckland's Hauraki Gulf - where crayfish numbers are falling rapidly.
A University of Auckland study has revealed that the crustaceans population has plummeted - even inside fully protected marine reserves, and numbers outside reserve boundaries are likely to be lower than previous estimates.
Researcher, Dr Nick Shears from the University's Institute of Marine Science the numbers crayfish in protected areas have dropped by 60-80 percent in the last decade or so.
This is despite being within a no fishing area.
He talks to Kathryn about what is causing the koura depletion.