Below this level, a fish stock is considered to be overfished or depleted and needs to be actively rebuilt, for example by reducing the total allowable catch.
"We spend about $22 million a year on scientific research to get the best available information about what is happening in our fisheries," Dr Ford says.
"All the scientific information we receive which goes into the stock assessments is independently peer reviewed by Fisheries Assessment Working groups to ensure the accuracy of information.
"If the science suggests that a stock is doing well, then we look at increasing catch limits. If the stock status assessment suggests that the catch needs to be reduced to ensure sustainability, then we propose reducing catch limits to re-build the stock," says Dr Ford.
Highlights from the review show that:
· The first ever successful assessment for Chatham Islands rock lobster was completed in 2018 and showed that the stock is above biomass limits, but below the management target.
· The Puysegur sub-stock of orange roughy was assessed in 2017 and found to have fully rebuilt since its closure in 1997.
To determine the status of each stock, a number of Fisheries Assessment Working Groups evaluate the results of scientific research vessel surveys, catch and effort reports, data from on-board Fisheries Observers and other relevant information.
New Zealand operates under the Quota Management System (QMS) to manage New Zealand's fisheries.
The status of the stocks is updated annually, and work on the 2019 update is already well under way.