For our enduring oceans, their sea life and our industry to thrive, there’s finally a better way to fish.
What is FloMo?
A Better Way to Fish
How can we select out under-size and/or non-target species?
How can we give those fish that escape or can be returned the best chance of survival?
How can we increase the quality of the landed fish to maximise the Fisher's financial return?
FloMo is a groundbreaking innovation that re-imagines the way we fish. The development brief was to create a design that addressed three perennial challenges the fishing industry faces: Selectivity, Survivability and Quality.
To do this, we started with the fish, interrogating and understanding their physiology and natural swimming behaviours.
Previous studies have shown that a traditional mesh codend limits the catch’s ability to maintain its natural swimming control due to factors like fatigue, the confined environment, and turbulence.
Simply stated, we needed to design a codend that could create a low-turbulence environment where the catch could maintain its natural state through the trawl and the lift.
We also needed the design to consider how undersized fish and non-target species could either escape during fishing, or if brought on board could be returned with the highest chance of survival on release. A decade later, FloMo is delivering against those challenges.
The FloMo codend is a composite fabric cylinder that hydrodynamically inflates using the directional flow of water created through a trawl.
Apertures of varying sizes and patterns are cut into the fabric cylinder to deliver a gradient of porosity and reduced water velocity throughout the length of the cylinder.
This allows the catch to naturally swim in this low turbulence environment, reducing fish-on-fish and fish-on-net damage. The aperture design also promotes the escapement of undersized fish or non-target catch, which are either ejected by the suction flow associated with water jetting outwards from the escapement holes or, in some instances, simply swim out.
In contrast to traditional mesh codends, the shape of the apertures in the FloMo can be tailored to target species and sizes, and their dimensions remain stable during fishing.
The terminal end of the FloMo allows the catch to be brought on board in a bag of water, not only minimising crushing damage and maintaining the quality of fish destined for market but also greatly increasing the likelihood of survival for any catch returned to the ocean.
A Research and Science-led Approach
Most advances in fishing technology over the past 150 years have focussed on catch efficiency, with bigger vessels, bigger nets and new electronic tools to find fish.
But now we are moving into a new era, where the fishing sector, governments and society want technologies that are not only efficient but also minimise injury and damage to both the harvested catch and the catch that escapes or is released from nets.
This growing focus on welfare, sustainability and harvest quality inspired a team of scientists at Plant & Food Research to re-invent the way we fish. The challenge was to redesign mobile fishing nets into a system that first herded fish, then create a capture environment low in flow and turbulence that allows the fish to swim within their own tolerances, and at the same time allow small fish and non-target species to be gently selected out.
Furthermore, the researchers needed to find a way to bring the catch aboard without dewatering and crushing the fish. After more than a decade of government and industry funded research, prototyping, and extensive testing in commercial trials, a radical hydrodynamic membrane concept was developed that transitions mobile fishing nets into a new era, focussed on animal welfare, harvest quality and better sustainability outcomes.
An Industry Seeking Change
Taking the FloMo from concept to a technology ready for global impact is the result of a close collaboration between the New Zealand Seafood Industry and the New Zealand Government, with a vision to do things better, improve the way we harvest and handle our fish, and ensure that our fish stocks are maintained for future generations.
It’s a great case study of the private and public sectors coming together to genuinely make change that benefits all parties commercially, socially, and environmentally. Investing in prototyping, trials, and ongoing development has significantly transformed a concept into a product now operational in New Zealand and being trialled in Europe.
The Resulting Innovation
FloMo (previously called the Modular Harvesting System) is a patent-protected technology (WO/2014/140702) that attaches to the belly of the trawl and replaces the extension/lengthener and codend sections.
Constructed from custom-designed, high-strength composite fabrics, the FloMo is made up of different modules that work together to generate a low-turbulence, low-damage hydrodynamic environment that gently filters incoming catch and allows it to be hauled aboard without dewatering (although dewatering is an option).
The Cone Module attaches to the belly of the trawl and helps direct the water flow induced by towing into the subsequent modules. As the water flows through the Retention Modules the internal pressure keeps the FloMo inflated like a windsock.
The Retention Modules have hundreds of escapement holes, which not only progressively reduce water speed, they generate a stable, membrane-like surface that gently filters the herded catch. Escapement holes can be designed to suit the target catch by changing the shape, size, and pattern cut into the composite fabric.
The Liftbag Module is FloMo's terminal module. It does not have any holes, and when deployed, the opening is rolled up and chain-stitched closed to create a blind end. Water flow into the Liftbag pressurises and inflates it, and along with the Cone Module pulls the fabric structure taut and creates a membrane-like filter surface along the Retention Modules. The Liftbag enables the catch to be brought aboard in water, or if necessary, the catch can be rapidly dewatered as it is lifted using a modified design.
Trawl operations using FloMo are similar to those with a conventional mesh codend. The one major difference is that the solid fabric Liftbag can be hauled aboard with water inside.
The catch displaces water in the Liftbag as the FloMo comes out of the water, so the volume of water coming aboard will vary from the full Liftbag volume to no water, depending on catch volume. To maintain fish quality, the recommended catch volume for a given Liftbag size is 50 % of the Liftbag volume.
As the catch can be maintained in water inside the FloMo until unloading onboard, it removes a major source of damage during haul back, namely the abrasion and crushing damages a fish experiences when pulled out of the ocean in a traditional codend.
The low-turbulence environment that FloMo delivers through the trawl, is designed to reduce the known causes of fish damage, such as abrasion, compression, fatigue, and stress. FloMo’s unique design results in a graded, largely linear flow regime that allows fish to swim within their own tolerances.
By providing a stable hydrodynamic environment, fish can maintain their natural swimming ability and take care of themselves. This reduces fatigue and stress and avoids compaction and death of exhausted fish at the back of a codend during the fishing process.
Not only does this result in better quality catch for harvest, but it maximises the amount of time fish are available for filtration by the hundreds of escapement holes, and the subsequent survival of fish that escape or are released from the FloMo after unloading.
In addition, if fish aren’t dying or getting injured during the capture process, this decouples tow duration from fish quality, opening up new possibilities for more efficient fishing operations. Better for the fish, better for the fisher.
