The key is the cage that replaces the conventional codend. It has been going through a process of constant development, but the results are clear as the Better Fishing cage has reduced juvenile fish mortality by a massive 94% while an 80% reduction has been achieved for elliptical fish.
‘Our goal is 100% selective fishing and we are also very keen to focus on humane treatment of fish,’ he said. ‘These are sentient creatures and this is something that deserves to be honoured.’
Karl and Sarah Warr have been running the trawler for the last fifteen years as a family business and he said that during that time social expectations and stakeholder conflicts have resulted in diminished public respect for demersal trawling, at the same time as New Zealand’s fisheries are increasingly channelled towards a small number of large companies.
‘These companies here pay very little for the contract catching of their fish quotas. Quotas have led to monopoly and the asphyxiation of most small operators through unprofitability,’ he said.
Better Fishing concentrates on flatfish and gurnard, working largely on quotas they have purchased. Fish are processed on board and sales are to local consumers and restaurants, with social media playing a central role in reaching the customer base.
‘By eliminating all links in the chain between us and the market, we can catch 80% less volume and make more income. Less expenses, less quota hassle. By being selective our fish is better quality and no quota is needed for fish we don't want,’ Karl Warr said.
‘The public like our ethics and other stakeholders respect our contribution toward lifting fish abundance. We have also tested our marketing concept in Singapore, which worked very similar to how it does locally in New Zealand, but with much higher values on product sales.’
The hardware is straightforward, a long steel cage made in 4mm 316 stainless steel rod with clearance between the bars that provides 100mm by 50mm apertures through which small fish are able to escape – and this happens at harvesting depth, eliminating the mortality problems associated with discarding fish at the surface after they have been through significant pressure changes.
The cage is rigged with floats to keep it buoyant and it does not make bottom contact while towing.
‘Panels of various shaped apertures can be interchanged for assessing optimal filtering of catch. The back and floor of the cage provide a low pressure front which fish use to recover and select escape opportunities,’ he explained.
The standard trawl and the cage with its wood floor are towed behind Karl’s 11 metre trawler Chips, and he describes the cage as being an interim design, as he foresees potential for the idea to be taken much further in terms of selectivity.