/ Environmental impact / Tuna, FADs and bycatch

Tuna, FADs and bycatch

Albacore Tuna © Dr Lindsay Marshall www.stickfigurefish.com.au
Tuna specialist and fisheries assessment manager, Dr Adrian Gutteridge on Fish Aggregating Devices.
Dr Adrian Gutteridge on April 12, 2016 - 9:37 am in Environmental impact, Sustainable seafood
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Updated on 1 November 2016

Global campaigns for sustainable tuna fishing have called for a ban on the use of Fish Aggregating Devices – also known as FADs. However, ‘FAD’ does not always mean ‘bad’. The impacts of this fishing practice need to be considered in the context of that particular fishery and ecosystem.

What exactly are FADs and are there different types?

Fish Aggregating Devices (FADs) are man-made, usually floating wooden structures with hanging nets to attract fish. These rafts can either be free floating (known as drifting FADs or dFADs) or anchored to the seabed (known as anchored FADs or aFADs).

Some tuna fisheries also target natural structures or objects, including free-floating logs (tree trunks) and large marine animals, such as whale sharks, around which fish congregate. This is referred to as ‘natural-associated’ or ‘object-associated’ fishing.

By deploying their nets and casting their lines close to these floating objects, tuna fishers can increase their catches of tuna.

What are the problems with using FADs?

A wide variety of marine life like tuna, turtles and sharks congregates around them. These species can become entangled in the floating nets attached to FADs. They can also be caught as bycatch in the same nets or lines used to catch tuna.

Bycatch of non-target species when fishing around FADs can be high, particularly in comparison to other methods of tuna fishing such as free school fishing, where nets are set in the open water. High amounts of bycatch can have detrimental impacts on the sustainability of these species. It can also increase the capture of juvenile tuna, putting the sustainability of particular tuna stocks at risk.

However, different species interact differently with different types of FAD, and different fishing techniques can make dramatic differences in the level of bycatch.

What can be done to reduce the impacts?

The capture of bycatch and non-target species around FADs is usually associated with purse seine fishing operations. Here fish are encircled with a large net which is then drawn closed at the vessel (like a purse), catching the fish inside the net. Other more selective fishing methods such as purse seine fishing on free schools of tuna (those not associated with Fish Aggregating Devices or other floating objects), pole and line fishing or trolling result in less bycatch. However, these other methods may have their own impacts which need to be considered carefully.

The advent of “eco-FADs”, which don’t use hanging mesh, are also thought to limit the number of entanglements. The impacts of FADs also need to be considered within the particular marine ecosystem, accounting for its unique mix of species and how they congregate around different types of FAD. For example, bycatch around anchored FADs (aFADs) which are located closer to land, can be lower than bycatch associated with drifting FADs (dFADs), which float freely in open water.

Developing more robust FAD management is an area of focus for many fisheries organisations, NGOs and the Regional Fisheries Management Organisations (RFMOs) that manage tuna stocks. For RFMOs, management measures include limiting the number of FADs that are deployed, promoting the use of biodegradable materials and developing management plans to address the impacts of FAD fishing and the numbers of FADs that are currently deployed.

Maldives pole and line fishery

The MSC certified Maldives pole and line tuna fishery uses a selective fishing technique to reduce bycatch.

What is the MSC’s approach?

Certification to the MSC Fisheries Standard is based on comprehensive assessment of the impacts of a particular fishery and the environment within which it operates. Therefore, because of the variations in the impacts that different FADs and fishing techniques can have in different marine environments, the MSC Fisheries Standard does not include specific requirements for FAD use, nor does it prohibit the use of FADs.

However MSC requirements that any impacts on bycatch species are sustainable mean that fisheries using FADs with high or unknown levels of bycatch can struggle to achieve certification. There are currently no purse seine fisheries certified to the MSC Fisheries Standard for tuna caught using drifting FADs. However, there are some purse seine fisheries on free schools (“unassociated” with floating objects) that are certified, and there are currently two MSC certified fisheries which catch tuna associated with anchored FADs.

All MSC certified tuna fisheries, regardless of their fishing techniques, have been assessed as having rates of bycatch which do not pose a long term threat to any species within the ecosystem where they operate.

We believe that by incentivising sustainable tuna fishing, the MSC program can be part of an evolution to more sustainable fishing practices. In the case of tuna fishing this incentive could encourage more fishers to adopt free school fishing methods, as we are already seeing in the MSC certified PNA fishery. It might also lead to new ways of reducing any unsustainable impacts of fishing on FADs – and stricter controls to ensure that these are followed.

We see considerable research being undertaken by the fishing industry to reduce the environmental impacts of FADs. Through these innovations and improvements, we believe that fishers can continue to catch tuna in a way which is both profitable and sustainable.

Further reading

Sustainable tuna: Challenges and solutions >

The role of anchored FADs for coastal tuna fisheries (IPNLF) >

International Seafood Sustainability Foundation (ISSF) On FADs > 

Dr Adrian Gutteridge

Fisheries Assessment Manager at MSC
Dr Adrian Gutteridge, Fisheries Assessment Manager at the MSC focussing on tuna fisheries. His work involves ensuring that certification bodies correctly apply the MSC Fisheries Standard when assessing fisheries targeting tuna and other highly migratory species. Adrian lives in Sydney, Australia and loves being in the ocean and cooking prawns on the barbie.

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