How FADs Affect Recreational Billfish Fisheries

Floating debris and other fish-aggregating devices can create an “illusion of plenty” when analyzing billfish stocks

billfishing in FADs and debris offshore
FADs can have a negative affect on billfish conservation and stock analysis because they attract fish — and result in catch rates — that are not true representatives of the entire fishery.Pat Ford

As beautiful as it is, the open ocean is a barren place that is largely devoid of structure, and any piece of floating debris — big or small, natural or manmade — is, at times, capable of attracting a staggering diversity of marine critters.

For this reason, fish and anglers alike are drawn to weed lines, cargo pallets, and every conceivable manner of flotsam and jetsam. And for centuries, industrious humans have been constructing fish aggregating devices to concentrate and harvest fish. As early as the 17th century, Mediterranean anglers constructed FADs that were anchored to the seafloor in relatively shallow water. Today, moored FADs can be deployed in depths of more than 2,000 meters, and over the past several decades, free-floating or drift FADs have colonized the open ocean.

"Whether or not you like to fish around FADs, they can have some negative implications on recreational billfish fisheries."

Commercial fishermen deploy the vast majority of FADs, and it is estimated that more than 120,000 drift FADs were deployed in 2013 alone. The purse seine FAD fishery has become a global issue because it leads to the overharvest of juvenile yellowfin and bigeye tuna that congregate in large numbers around FADs. Recreational billfish anglers are also big into the FAD game now. In the past several decades or so, FAD-associated billfish hot spots have popped up in places like Costa Rica, the Dominican Republic and others that are reporting amazing numbers of marlin raised and caught. The social implications of these fisheries have been a common topic of late. Some equate fishing around FADs to shooting fish in a barrel, while others contend that FADs have the ability to greatly shorten the learning curve for both anglers and crew.

Whether or not you like to fish around FADs, they can have some negative implications on recreational billfish fisheries. A report written for the FAO by billfish experts at the University of Miami working on a regional billfish conservation and management project in the Caribbean indicates that recreational and commercial billfish catches made in association with FADs muddle catch-per-unit effort indices, which are used by scientists to estimate billfish abundance. The problem is that FADs have the ability to accumulate billfish biomass independently of true stock abundance. That is, catch rates associated with FADs can remain stable, or even become elevated, as true stock abundance actually decreases. In this "illusion of plenty," unnatural densities of billfish are mistaken for a healthy stock, which can lead to improper management.

Moored FADs are widely used in the Caribbean by fishermen targeting tuna, mahimahi and other pelagic species. Unfortunately, they also incur high levels of billfish bycatch. In the FAD fishery off Martinique, billfish account for upwards of 51 percent of fish commercially landed, and it’s estimated that the majority of blue marlin landed in the eastern Caribbean comes from FAD‑associated fisheries.

FADs in the Caribbean have also sparked a bit of a turf war in some areas: Heated disputes, sometimes approaching physicality, have erupted over who has the right to fish a given FAD. Marlin hijackings are also becoming more commonplace, where disgruntled commercial anglers “commandeer” billfish that are being fought or released by recreational anglers.

So, like ’em or not, there’s more at stake with FADs than whether you consider them sporting. Even well-­intentioned FADs deployed by anglers for catch-and-release purposes can be found by commercial fishermen who don’t have a marlin’s best interests in mind. In the end, global billfish populations are not faring too well in most places, so it doesn’t make sense to deploy FADs in countries where they can be commercially exploited and where regulatory frameworks can’t prevent FADs from exacerbating the ­overfishing that’s already occurring.