As the second-largest tuna-consuming country in the world, the United States is responsible for the consumption of 31% of the world’s canned tuna products. But is the tuna you consume sustainably caught?
To be a more conscientious consumer and appreciate the value of FAD-free tuna, it’s important to first understand the most widely used commercial fishing method for catching tuna: fish aggregating devices (FADs). So let’s do a deep dive into the reasons for the use of FADs and the problems they create for our oceans.
Some marine life species are attracted to floating objects. For the fish that flock to them, these objects provide a sense of safety from predators above the water. They also serve as a source of food because the object begins to grow barnacles and mussels.
When schools of fish take up residence under a floating object, it’s natural that other marine life, such as sharks, will come to feed on the fish that live there. Before long an ecosystem is formed.
This floating object could be as benign as a log or branch. But more often than not, particularly in the tropical oceans, it is a trap known as a FAD.
What is a FAD?
After realizing that tuna fish tend to congregate under floating objects, it didn’t take long for fishers to realize how they could benefit from this knowledge. Then fish aggregating devices (FADs) became an industry standard.
FADs account for more than 40% of tuna caught annually, with tens of thousands of these devices deployed.
FADs can be broken down into further categories:
- natural or man-made
- anchored or drifting
The natural objects, like fallen trees, are found by fishermen and modified for their use. The man-made objects, however, are designed specifically for tricking the fish into gathering in a designated location. This artificial practice makes tuna fishing less like hunting and more like harvesting.
In their earliest days, FADs were hand-assembled bamboo rafts set adrift with the current and then later used to fish from. By contrast, today’s FADs are usually much more complex and technical, with a solar-powered satellite transmitting the FAD’s exact location to a purse seine boat and a sonar device remotely allowing the fishermen to track the number of fish congregating beneath the FAD.
To the untrained eye, these FADs can appear to be unmanned rafts or rogue barrels. Nonetheless, often there are ropes hanging beneath the surface of the water or high-tech radio transmitters signaling their location.
Drifting Fish Aggregating Devices (dFADs)
These FADs, which are usually man-made rafts, float slowly along with the current, often following the migration path of tuna. Beneath the water, dFADs drag long pieces of old fishing nets, ropes and plastic ribbons used to slow their catch’s movement. Aboveboard they are equipped with GPS and satellite for easy tracking, as well as sonar for easily and remotely counting the adjacent fish.
Anchored Fish Aggregating Devices (aFADs)
These FADs, which can be either man-made or natural materials anchored to the ocean floor, are used less often than the kind that drift, but they have a big advantage. Because aFADs are anchored — sometimes as much as four kilometers beneath the surface — they do not need sophisticated tracking equipment. Also, aFADs are more likely to be used for one-by-one fishing methods.
How FADs Work
Once the tuna fish have sufficiently aggregated beneath the FAD, a boat arrives to harvest the tuna fish. Frequently, this is a purse seine boat. A purse seine is a vertical net ‘curtain’ that is used to surround the school of fish. Then the net is drawn together and lifted in the manner of a drawstring purse.
This method of fishing proved effective and seemed like good news for the tuna industry. As with any part of nature, however, it wasn’t long before human impact was evident.
The Primary Problems with FADs
The most easily recognizable problem with FADs is overfishing. This is what happens when fishermen catch fish faster than their stocks can replenish, and this outcome is what happened to the once common bigeye tuna.
Unwanted fish and nontarget species caught during commercial fishing are known as bycatch. The use of FADs is estimated as 2.8 to 6.7 times more likely to return bycatch than non-FAD fishing. FAD bycatch frequently includes juvenile tuna and endangered sharks or sea turtles.
Not only do the purse seine boats bring up bycatch with their nets, but the FADs themselves frequently capture and kill bycatch in the hanging nets and ropes that dangle beneath the FADs. One study of FADs in the Indian Ocean found that the number of silky sharks killed through entanglement in a dFAD’s ropes and nets were 5-10 times greater than those caught by purse seine nets that were meant to actually harvest fish.
Discarded and lost fishing gear adds to the ever-growing amount of ocean trash that tangles on reefs and traps marine life. This waste is commonly known as “ghost gear,” which is particularly harmful to marine life given that its originally intended use was for capturing fish.
Years after it is lost and abandoned, ghost gear continues to capture fish, sea turtles and even whales. It is also increasingly made of plastic. An estimated 12 million tons of plastic ends up in the ocean every year, and ghost gear accounts for 10% of that oceanic plastic waste.
The Downsides of dFADs and aFADs
Although there are more dFADs deployed than ever before, fewer of them are actually fished on. Because the fishers are able to check the amount of fish aggregated from a distance, more and more dFADs are intentionally abandoned at sea.
Though anchored, aFADs can break free in bad weather. Once these aFADs are set adrift aimlessly, they not only contribute plastic, metal and electronic waste, but they wreak havoc on the ecosystem.
What’s Being Done?
By 2009 tuna stocks had fallen 32% below what they were before fishing became industrialized. In response to this depletion, the Western and Central Pacific Fisheries Commission instituted an annual ban on the use of FADs. This ban is in effect every year from July to September.
These bans have had little effect. Even though fishing stops for three months, many FADs aren’t actually removed from the water.
There have been complications regarding the definitions surrounding FAD and FAD set (the group of fish caught with the use of the FAD). Until these legal issues are resolved, FADs remain in the water, and the number of fish surrounding them continues to increase. As a result, these FADs yield a greater haul when the fishers arrive after the ban is lifted.
The United Nations has been negotiating the Global Ocean Treaty, which would allow 30% of international waters to become ocean sanctuaries by 2030. Hopefully this measure will be more effective.
What Can I Do?
Next time you order sushi or make a tuna sandwich, learn about the fishing methods used to catch your dinner.
- Choose skipjack tuna instead of yellowfin or other species, as skipjack is more often sustainably caught.
- Make sure the tuna you choose is labeled as being caught through “pole-and-line” or “FAD-free” methods.
- Remember that if the tuna can does not provide this information, it is most likely not FAD-free tuna.
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