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Are Fish Aggregating Devices just a FAD?

Blog by: Lindsay Brubaker, Blue Parks Science Intern

Featured Image: A view from below of a fish aggregating device (FAD). Wade Fairey

Fish Aggregating Devices—called FADs—result in five times more bycatch than other fishing methods, and lost FADs become ghost gear, costing millions of dollars in cleanup efforts in fragile ecosystems. These floating ocean objects take an enormous ecological toll, but there are answers for minimizing their impact.

A fish aggregating device, or FAD, might be made out of any number of materials, from polyurethane foam and nylon nets to steel oil drums and iron framing. It might be anchored in place or drift with the current. These man-made floating objects, used primarily by fishers, are designed to attract and aggregate fish such as tuna or mahi mahi that are naturally drawn to items floating in the ocean like seaweed or driftwood. By using FADs, fishers can create high densities of commercially valuable species in a single, known area and catch more fish per unit effort. An attached satellite beacon allows the fishers that deployed it to locate the FAD and return to it for easy fishing, and sonar equipment can let them see how many fish are congregated around it. This technology also allows fishers to reduce their fuel costs (and carbon emissions) by taking the shortest route to an area with guaranteed abundance. [1]

However, FADs have been criticized for their many ecological costs including entanglement and bycatch, overfishing of juveniles, harm to marine protected areas (MPAs) and sensitive habitats, proliferation of ghost gear, and violation of the International Convention for the Prevention of Pollution from Ships (MARPOL). [1, 2]

Sharks are often caught as bycatch in nets or FADs. Photo: Tom Vierus/Coral Reef Image Bank

Entanglement, Bycatch, and Overfishing of Juveniles

Fish, sharks, rays, turtles, and other megafauna are easily entangled and injured in the ropes and nets of FADs, and when they are unable to escape, they drown. [3] Species not targeted by fisheries may still be attracted to FADs, thus increasing their risk of being caught as bycatch. It is estimated that vessels that fish using FADs capture five times more bycatch than those that do not. [4] In the tuna industry, FADs are accompanied by the use of high-impact purse seines, which have large walls of netting that capture everything they surround, ranging from tuna to dolphins and turtles. The crushing weight of the fish in tow often crushes and kills those caught unintentionally. Using FADs in tandem with purse seines also increases the risk of catching juveniles, which can fast-track the depletion of a species. It was estimated that in 2018, 53-89% of tuna sold was associated with FADs. [1]

Fishing vessels often use purse seines to capture fish surrounding FADs. Photo: Jiri Rezac

Harm to Marine Protected Areas and Sensitive Habitats

In addition to increasing bycatch and entanglement, drifting FADs (dFADs) float across the ocean, often crossing national Exclusive Economic Zones (EEZs) and MPA boundaries, where they may be illegal and put sensitive and protected habitats and species at risk. [1] For example, the Phoenix Islands Protected Area, a 408,250 km2 no-take MPA, is a highly productive tuna spawning area. [8] Illegal dFADs have been found within the MPA, but enforcement and penalization have proven difficult. Since vessels wait until their dFAD has drifted outside of the MPA and are not technically ‘fishing’ within the MPA (towing gear in the water), there are questions about whether these fishers can be held accountable for the dFAD. Several recent studies concluded that FADs are considered fishing while drifting, which means that enforcement authorities could legally act. [1, 8] However, even with legal authority, finding a FAD in a vast MPA such as the Phoenix Islands can be challenging, and in the meantime, dFADs cause their usual trouble, entangling fish and trailing through sensitive ecosystems.

Similarly, just outside the boundary of Galápagos Marine Reserve (an awarded Blue Park), fishing vessels deploy dFADs that float through the MPA and attract an abundance of tuna, as well as threatened sharks, from the flourishing protected populations. The vessel waits for the dFAD to lure fish outside the MPA boundaries and proceeds to catch them. [7, 15] In the Galápagos, large fishing vessels can cast up to 500 FADs, known locally as plantados, outside the marine reserve, relying on currents to push them back outside the MPA where they can hunt the tuna attracted by the plantados. [7] To prevent the fishing pressure from FADs as well as industrial fishing fleets, Ecuadorian scientists and community groups support a proposal to expand protections around the Galápagos Marine Reserve (this campaign joined the Blue Parks network as a Blue Spark earlier this year). Since vessels utilize the South Equatorial Current to naturally float FADs from east to west through the MPA, part of this proposal includes setting a FAD-free fishing zone to the east of the MPA, therefore preventing the usage of the current and of FADs within the MPA. [15]

Ghost Gear and Pollution

Since dFADs are not fixed to one location, it is common for them to get lost. Of over 121,000 FADs deployed each year, over 60% are abandoned, lost, or stolen. [1, 5] Legally, dFADs that are lost or abandoned are considered a violation of Annex 5 of MARPOL, which prohibits dumping of garbage into the ocean. Flag states must penalize violators of MARPOL, but unless a FAD is reported lost by the ship itself or is found and traced back to the ship, penalization is impossible. [6] Abandoned dFADs thus become “ghost gear,” and though they are not monitored by their fishing vessel and therefore are not being used to catch fish, they still attract fish.

Volunteers laboriously removing abandoned nets from a coral reef. Photo: Shaun Wolfe/Coral Reef Image Bank

Over time, abandoned and lost FADs begin to degrade, polluting the ocean. They can become stuck on coral reefs or other structures. In a period of two weeks, there is a 37% chance that a dFAD will become trapped and harm sensitive marine habitats. [2] In a period of just three years, 95 abandoned FADs were found among the seagrasses and coral of the British Indian Ocean Territory, a 640,000 km2 MPA. [11] Moreover, since 98% of FADs are made of plastic, many become sources of microplastics as continuous wave action breaks them down. Microplastics are consumed, along with phytoplankton, by larger predators, and when they are eaten, the microplastics bioaccumulate up the food chain.[9] Microplastics also impact the development, survival and fertility of fish.[10]

Removal of FADs can be laborious and costly, especially when they end up in remote areas, like Aldabra Atoll, a Blue Park and UNESCO World Heritage Site in the Seychelles. Clean-up efforts in 2019 removed 25 tons of marine debris; with the heaviest 60% comprised of nets, FADs, and buoys from the fishing industry, with cleanup costing $224,537. [13] This removed only 5% of the total debris on the island; removing the rest is estimated to cost $4.68 million and take 18,000 hours. [13] This makes the cleanup of marine debris, including FADs, inequitable, as many places lack the manpower and financial resources to undertake such a cleanup, and there is no structure in place to hold the fishing vessels that deployed the FADs financially accountable. 

What should we do about FADs?

So how do we solve the problems associated with FADs? Clearly, fishing vessels should be held accountable for FADs. Currently, there are minimal requirements for sharing the tracking information for FADs, which makes monitoring them extremely difficult. Instead, Bradley Soule, Director of Intelligence for Oceanmind, a nonprofit that encourages fishing compliance, suggests that vessels be required to use Automatic Identification System (AIS) to track FADs, which would make the tracking data openly available and is already employed in Europe to mark longlines and gill nets. [14, 16] This would make finding FADs and connecting them to their owner much easier, and enforcement strategies, such as fines, could incentivize owners to keep better track of their gear, meaning less gear in the water to entangle animals and release microplastics. FADs are legally considered fishing devices, so releasing them into MPAs is illegal, as is their abandonment under MARPOL. With stronger tracking and enforcement, fishing vessels could be fined for breaching these regulations.

The design of FADs could also be adapted to decrease the possibility of entanglement; they could be made from biodegradable materials, and the purse seines used by fleets around FADs could use larger mesh or include escape panels for unintentionally caught species like sharks and rays. Though FADs harm fish populations and marine protected areas, as well as release microplastics into marine food webs, it is clear that solutions exist to better regulate them and mitigate some of these negative impacts. All we have to do is take action.


1. Gomez, G., et al (2020). The IUU Nature of FADs: Implications for Tuna Management and Markets. Coastal Management 48 (6): 534-558.

2. Curnick, D., et al (2020). Risks to large marine protected areas posed by drifting fish aggregation devices. Conservation Biology.

3. Worm, Boris. Fish Aggregating Devices (FADs) in Responsible Tuna Fisheries. 6th May 2021. Webinar hosted by Blue Marine Foundation.

4. Mongabay (2021). European tuna boats dump fishing debris in Seychelles waters ‘with impunity’. Retrieved May 12 from

5. Gershman, D., A. Nickson, and M. O’Toole. 2015. Estimating the use of FADs around the world: An updated analysis of the number of fish aggregating devices deployed in the ocean. Pew Environment Group 1–24.

6. Churchill, R. Fish Aggregating Devices (FADs) in Responsible Tuna Fisheries. 6th May 2021. Webinar hosted by Blue Marine Foundation.

7. The Guardian (2021). The fight for the Galápagos: race to expand reserve as fishing fleets circle. Retrieved May 12 from

8. Hanich, Q., et al (2019). Drifting fish aggregating devices (FADs) deploying, soaking and setting – when is a FAD ‘fishing’?. International Journal of Marine and Coastal Law 34: 1-24.

9. Escalle, L., et al (2018). ‘Evaluation of dFAD construction materials in the WCPO’ presented at the Fourteenth Regular Session of the Scientific Committee to the Western and Central Pacific Fisheries Commission (SC14-PP-EB-IP-01, Busan, Republic of Korea, 8–16 August 2018).

10. Burt, April. Fish Aggregating Devices (FADs) in Responsible Tuna Fisheries. 6th May 2021. Webinar hosted by Blue Marine Foundation.

11. Clark, M., et al (2015). Update on the catch and bycatch composition of illegal fishing in the British Indian Ocean Territory (BIOT) and a summary of abandoned and lost fishing. MRAG Ltd, London.

12. J Witting, ‘Report of FAD transponder float collection on Nikumaroro Island, Phoenix Islands Protected Area, during SEA Cruise S-281, 4–5 August 2018’ submitted to PIPA Implementation Office and PIPA Conservation Trust (2018).

13. Burt, A., et al (2020). The costs of removing the unsanctioned import of marine plastic litter to small island states. Scientific Reports 10: 14458.

14. Soule, Bradley. Fish Aggregating Devices (FADs) in Responsible Tuna Fisheries. 6th May 2021. Webinar hosted by Blue Marine Foundation.

15. Hearn et al (2021). A Proposal for Marine Spatial Planning of Ecuador’s Exclusive Economic Zone around the Galapagos Marine Reserve, pp. 9, 14.

16. Panbo: the Marine Electronics Hub (2020). AIS fishing net buoys, the wrong way & the right way. Retrieved May 2021 from