Scientists are about to start a survey of the nation's estuaries to try to find the nursing grounds of a small shark.
The rig shark, also known as lemon fish, is commonly used in fish and chips.
Scientists from the National Institute of Water and Atmospheric Research will set nets around 14 estuaries in the North and South Islands as they try to establish which are most important for juvenile sharks.
Lead NIWA scientist Malcolm Francis saysknowledge about where rig sharks grow up is only rudimentary and this will be the first time most of the estuaries are studied properly.
Dr Francis says most of the big harbours have cities on their back doorstep so it is important to find out which the shark uses most and establish the human impact on the fish.
The survey begins next week and will take about a month.