Case study: Precision seafood harvesting

Precision seafood harvesting, also known as modular harvesting, has resulted from 10 years of development effort as part of a joint-funded research programme between the Government, Sanford Limited, Sealord Group Limited and Moana New Zealand. The new technology has been based on understanding fish physiology and behavior which has enabled the development of a trawling system that is better able to target selected species and land them in an improved condition. If the new net technology works as hoped, it has the potential to produce higher quality fish , reduce the numbers of juvenile fish killed, and increase the probability of bycatch species being released alive. 1933

The new system replaces part of the traditional trawl net with a flexible PVC landing liner which is dotted with escape portals. During a trawl, undersized and non-target species are more likely to be able to escape the net through the escape portals. This means that they can freely return to the sea, without being boarded on a vessel, and this greatly reduces any physiological stress. Targeted fish continue to swim at a natural pace, within the liner, until such time as they are landed. This method is far gentler than traditional methods, where fish are forced down to the cod end of the net and hauled along at speed, and fish remain alive until they are landed. 

Trials using the new method have shown that juvenile snapper caught in the net, but able to swim out before it is hauled aboard, have a 90 per cent survival rate in the first 24 hours post-harvest. 1934 For targeted species, the much greater probability of being alive when the net is hauled, improves catch quality and may result in more opportunities to export to live fish markets. In addition, the technological development means that any bycatch, which can include species too large to escape through the escape portals such as shark or rays, can be re-released with a good chance of survival. 1935

Last updated at 4:21PM on November 23, 2017