Background on FADs
The term FAD stands for “fish aggregating device”, and generally refers to artificial structures that are deployed in the ocean to attract schools of fish. FADs function as open-ocean “meeting points” with multiple species gathering underneath them. It is generally believed that fish use these floating objects for protection, increased food availability, and to increase survival of eggs, larvae and juvenile stages of development1.
Artisanal fishermen throughout the world have been using various types of FADs for hundreds to thousands of years to increase their catches.2 However, since the late 20th century, FAD use in the world’s oceans has soared due to the new technologies that have allowed for their widespread use by industrial-scale purse seine vessels targeting tuna. Based on conservative estimates, over 20,000 drifting FADs are actively monitored by the global purse seine industry3 – the majority of which will remain in the ocean until removed or destroyed.
Today’s drifting FADs are often times technologically advanced – equipped withlocation transmitters and sonar devices to remotely inform vessel operators of their location and the tonnage of fish aggregated. While FAD fishing can be an efficient method for catching large schools of tuna, industrial-scale FAD fisheries can have significant adverse impacts on tunas and other species.
The impact of FADs
Overall, information on FAD use is not widely available because information on their exact numbers and locations is considered proprietary by industrial fishing vessel operators and fleets. However, based on a synthesis of peer-reviewed literature on FADs4, their widespread use has already had numerous adverse impacts, including:
- Recruitment overfishing of skipjack tuna in the eastern Atlantic Ocean;
- Overfishing of bigeye tuna in the western and central Pacific Ocean, and potentially in the eastern Pacific;
- Decreased weight of tunas caught near FADs compared to tunas caught in freeschools;
- Increases over time in fish biomass under FADs5;
- Reduced free-school abundance;
- Differences in fish sizes and ages compared to free-school caught tuna;
- Alterations in school movement patterns across the Pacific Ocean;
- Increased difficulty of properly assessing the status of individual tuna populations; and\
- High volumes of bycatch including sharks, sea turtles and juvenile tunas.
Moreover, research suggests that networks of thousands of FADs could act as “ecological traps” for open-ocean species by altering their natural distribution patterns, habitat associations, migration, and residence periods. Over time, the proliferation of FAD use may cause widespread alterations in the structure and function of these ecosystems.
Current Attempts at FAD Management
Some Regional Fisheries Management Organizations (RFMOs) have measures in place aimed at managing the impacts of FAD fisheries on non-target tunas and other non-target species. These include FAD closures, total fishery closures, and FAD inventory programs. To date, these measures have not achieved their objectives - partly because the number of FADs deployed is uncontrolled. There is also important ongoing research into FAD fishing methods that could reduce catches of juvenile tunas.
Reducing the Impact of FADs Approximately half of the global tuna catch comes from FAD fisheries. These are lacking in measures to manage their impacts. In order to maintain sustainable catches and healthy ocean ecosystems, these fisheries should be managed in accordance with the precautionary principle and ecosystem approach with specific measures to account for the impacts of FADs on tuna populations as well as associated and dependent species. We urge countries and RFMOs to implement targeted measures regarding FADs that are highly precautionary, until such time as the ecological impacts of FADs are better understood and scientifically proven techniques for mitigating their ecological impacts have been fully implemented. Such measures should specifically manage and control the wide-scale use FADs so as to:
- avoid overfishing target tunas;
- minimize bycatch of non-tuna and other nontarget species; and
- avoid significant or adverse changes to open ocean ecosystems.
Considering the uncontrolled proliferation of FADs and the lack of comprehensive management measures to regulate their use, the Pew Environment Group recommends a number of actions that countries and RFMOs should take immediately to address industrial FAD fisheries before irreversible harm is done to open ocean ecosystems. Specifically, to both better understand the harmful impacts of FADs and to lessen those impacts, we recommend that countries and RFMOs involved in industrial purse seine fisheries should:
1. Mandate relevant RFMO scientific committees to:
Recommend scientifically-based catch limits for skipjack, yellowfin, and bigeye tunas, using scientific models that incorporate the catch of non-target juvenile tunas from FAD fisheries into these catch limits, and
Develop limits on the number of FADs allowed in an ocean area which ensures that the number of FADs in use is consistent with the recommended scientifically-based catch limits and results in minimal alterations in the natural distribution patterns, habitat associations, migration, and residence periods of large pelagic fish species.
In addition, RFMOs should:
2. Inventory and track all FADs in their respective convention areas to ensure understanding of their scope of use and enable effective regulation;
3. Undertake research and scientific trials to determine how to reduce catch of non-target species when fishing on FADs;
4. Require decommissioned FADs to be removed from the water;
5. Require drifting FADs to be removed from the water during FAD closures to stop “ghost fishing”;
6. Implement 100 percent observer coverage on large purse seine vessels to ensure compliance with FAD measures and provide data on catch composition to RFMOs.
If measures 1-4 above cannot be implemented in the short term, then fishing on FADs should be suspended by the RFMO in question until such a time as effective management measures have been adopted and implemented. Fishing on tuna schools unassociated with FADs (free-schools) is one feasible alternative. This type of fishing has significantly lower non-target catch, does not create ecological traps, and results in a catch that is often of higher quality.
1 Gooding and Magnuson 1967; Hunter and Mitchell 1968; Hunter 1968, Dagorn et al. 1995; Fréon and Dagorn 2000
2 Kakuma 2000; Morales-Nin et al. 2000
3 WCPFC 2009a, Hampton 2010, Moreno et al. 2007)
4 Morgan, A.C. 2011. Fish Aggregating Devices and Tuna: Impacts and Management Options. Ocean Science Division, Pew Environment Group, Washington, DC.
5 If a FAD is left in the water, even during a closure, result suggest that fish continue to aggregate, resulting in more fish being caught when fishing resumes than if the FAD had been removed from the water. This has been sometimes referred to as a form of “ghost fishing” as it ultimately results in increased fishing mortality.