Shelton Harley: Science ensuring healthy stocks

Many assessments of important fish stocks use catch datasets much more comprehensive than those submitted to the United Nations. Photo / NZME

Opinion

Rigorous assessments show sustainable abundance and new methods will further improve management.

Last week, a report attempting to estimate historical catch in New Zealand's waters was released to wide-ranging interest. This is not surprising since it claimed the "true" catch from New Zealand's fisheries between 1950 and 2010 was 2.7 times more than official figures suggest.

That statement might sound impressive, and it's certainly a useful way for the authors to market their research, but it is misleading and invalid.

The "official figures" the report refers to are those New Zealand reports to the Food and Agriculture Organisation (FAO) of the United Nations. The data requested by the FAO is only one small piece of information we have on catches and abundance for our fish stocks. Many of the assessments of important New Zealand fish stocks (orange roughy, snapper, paua, and rock lobster) use catch datasets much more comprehensive than those submitted to the FAO.

These scientific assessments incorporate historical knowledge of fishing practices, as well as observer and compliance information to generate the best information on total fishing-related mortality. The approach works, and we have decades of scientific assessment which shows sustainable levels of abundance.

The situation now is that New Zealand fisheries are healthy overall, because of science-based management. We focus our efforts on ensuring there are enough fish in the water for all of New Zealand's most important fish stocks. Our scientific assessments show that 96.8 per cent of landings of fish of known status come from stocks where sustainability is not a concern.

Does this mean that all of our fisheries are at the level we would want them to be all of the time? Of course not, and there are some stocks where we need active management plans, such as for bluenose and key snapper stocks.

We focus our efforts on ensuring there are enough fish in the water for all of New Zealand's most important fish stocks.

Sometimes we are confronted with localised depletion. We have experienced this with the blue cod fishery at the top of the South Island where we have worked with all fishers to put a new regime in place which will lead to a sustainable fishery.

In their piece for the Herald last week, the authors of the report said "fisheries science is complex and it is easy to misrepresent and muddy the waters". We couldn't agree more. We have some concerns about this report's methodology. Specifically we would expect that a scientific report of this nature would include details of the data used, assumptions made, and how the final estimates were derived.

For our part, we are talking with the researchers so this analysis can be reviewed and evaluated against the Research and Science Information Standard for New Zealand Fisheries, which requires that information be scientifically robust, peer-reviewed, relevant, objective and reliable.

We can agree with the report's authors on one point at least - this is too important to get wrong. The Ministry of Primary Industries' ability to better understand catch, and indeed all commercial fishing activity, is being significantly enhanced through the introduction of real-time electronic reporting.

These plans will use technology to greatly increase the quality and quantity of that information and ensure increased monitoring of commercial fishing activity leading to a significant increase in compliance.

The project, called Integrated Electronic and Monitoring and Reporting Systems, has been in development since 2014, with trials beginning in 2015, and we are currently investigating options to fast-track this project. It will mean monitoring of all catch on all fishing vessels.

The monitoring will provide detailed reports from vessels using a totally integrated reporting and monitoring system which combines on-board camera monitoring, vessel positioning data and real-time catch effort reporting. This system will be the first of its kind in the world and, once established, it will reinforce New Zealand's position as a world leader in fisheries management.

Dr Shelton Harley is the manager of fisheries science for the Ministry for Primary Industries.