Fish Aggregation Devices, do they worth the cost?

Fish Aggregation Devices

Unless you’re a fisherman, you’ve probably never heard of FADs. What you may be more familiar with, perhaps from movies about castaways adrift in the middle of the ocean (such as Unbroken), is the image of fish approaching the life raft just because it is the only thing floating in the salty desert. And the reality is not very different: any floating object in the middle of the sea can become a microhabitat that attracts organisms, including species of fishing interest. 

This is precisely what FADs (Fishing Aggregating Devices) consist of, floating structures designed to concentrate schools of fish, which would normally be spread over large areas, in the same place, thus facilitating their subsequent capture. There are two main types: 1) anchored FADs, which always remain in the same position; and 2) drifting FADs, which move freely wherever the winds and currents take them and are kept geolocated via satellite (FAO, 2012). The use of FADs has been increasing since the mid 90’s and are becoming more common all over the world. For instance, nowadays, approximately 70% of purse seine tropical tuna fisheries depend on FAD (Hallier & Gaertner, 2008). 

FADs may be an effective method for more efficient tuna fishing, but these devices are said to be one of the causes of worse tuna health status. Misleading habitat selection (animals are “forced” to select FAD areas where their prey is attracted too) and consequent changes in the feeding patterns related to poor habitats affects tuna nutrition, causing smaller sizes/biomass and less healthy individuals (Hallier & Gaertner,2008). In the end, although “efficient”, FADs have a huge impact on the sustainability of tuna population and thus, tuna fisheries. For example, an ecosystem model of the Western Pacific Warm Pool Province showed that reducing FAD effort by at least 50% on the Pacific Ocean can increase the biomass of tuna species and return the fisheries to a pre‐industrial‐fishing state within 10 years (Griffiths et al., 2019).

Unfortunately, FADs do not affect only tuna, but bring multiple problems for marine ecosystems and pose a threat to numerous species like sea turtles, seals, dolphins and whales that are also attracted to them. These cannot only be subject to bycatch but also can get entangled in the lines of the device itself, which can cause lacerations or even death by asphyxiation (NOAA,2017).

In 2018, it was estimated that only around 10% of deployed FADs were recovered by a vessel. When abandoned, they become marine litter and can cause the so-called “ghost-fishing” (Hallier & Gaertner,2008).

Indirect impacts that could alter cetacean populations have been identified, such as habituation to having food concentrated in the same area, which would not occur naturally (NOAA, 2017). This is known as “ecological trap” and could affect cetaceans in a similar way as mentioned in tuna, changing habitat selection.

For all these reasons, organizations such as the Word Cetacean Alliance, of whom Futurismo is a partner since its foundation in 2013, support initiatives to call for effective management of FADs, such as the letter coordinated by the International Pole & Line Foundation calling on delegates to the Indian Ocean Tuna Commission (IOTC):

It is worth mentioning that it is indeed possible to improve these devices, using anti-tangle designs without hanging lines or using biodegradable materials to mitigate the effects of lost devices (MSC, 2018). In fact, we at Futurismo can attest to this last point, as we found a lost FAD on one of our sea tours a couple of years ago.

The implementation of “Pingers” (dolphin deterrent devices), which are already used today in other fishing gears might also be an option to mitigate impacts on dolphin species. As a consumer, one way to fight against the impacts derived from these devices is to reject fish that comes from their uncontrolled use.  

Written by Jorge Pan Martinez

References:

Davies, T.K., Mees, C.C., & Milner-Gulland, E.J. (2014) The past, present and future use of drifting fish aggregating devices (FADs) in the Indian Ocean. Marine policy, 45, 163-170.

Hallier, J. & Gaertner, D. (2008) Drifting fish aggregation devices could act as an ecological trap for tropical tuna species. Marine Ecology Progress Series, 353, 255–264.

Hanich, Q., Davis, R., Holmes, G. et al. (2019) Drifting Fish Aggregating Devices (FADs). Deploying, Soaking and Setting – When is a FAD ‘Fishing’? The International Journal of Marine and Coastal Law, 34, 731-754.

Baidai Y., Dagorn L., Amande M.J., Gaertner D. and Capello (2020). Mapping tuna occurrence under drifting fish aggregating devices from fisher’s echosounder buoys in Atlantic Ocean. ICCAT, 76(6): 777-784 

Griffiths, S. P., Allain, V., Hoyle, S. D., Lawson, T. A., and Nicol, S. J. (2019)Just a FAD? Ecosystem impacts of tuna purse-seine fishing associated with fish aggregating devices in the western Pacific Warm Pool Province. Fisheries Oceanography, 28: 94-112

FAO (2012) Anchored Fish Aggregating Devices (FADs) for Artisanal Fisheries http://www.fao.org/3/ar482e/ar482e.pdf

NOAA (2017) Fishing Gear: Fish Aggregating devices https://www.fisheries.noaa.gov/national/bycatch/fishing-gear-fish-aggregating-devices

MSC (2021) What is FAD free Tuna https://www.msc.org/en-au/what-you-can-do/eat-sustainable-seafood/what-is-fad-free-tuna

MSC (2018) Tuna FADs and bycatch https://www.msc.org/en-au/media-centre-anz/news-views/2020/03/03/tuna-fads-and-bycatch

Morgan, A.C. (2011) Fish Aggregating Devices and Tuna: Impacts and Management Options. Ocean Science Division, Pew Environment Group. https://www.pewtrusts.org/~/media/legacy/uploadedfiles/peg/publications/report/pegosdfadsenglishfinalpdf.pdf

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