Since the guide for non-entangling FADs was released in 2012 by the International Seafood Sustainability Foundation (ISSF), three tuna RFMOs now recommend that fleets deploy these less-traditional devices. However their effectiveness can be argued as the Foundation itself says the FAD design is “not germane” in regards to the bycatch caught in purse seine nets.

The use of traditional FADs (DFADs) used to attract tuna has been criticized increasingly by ISSF due to their design which causes bycatch species, including sharks and turtles, to get caught in their nets, despite the foundation being one of the first promoters of FAD fishing. The large mesh netting in the DFAD creates the highest risk of entanglement resulting in direct mortality, according to ISSF. Therefore, the Foundation developed the concept of non-entangling FADs which it states have a lower risk of entanglement.

ISSF says the use of non-entangling FADs is “likely to have avoided the mortality of between half a million and a million small silky sharks in the IO” so far. The IOTC, IATTC and ICCAT all require vessels to transition to non-entangling FADs. A “properly designed” non-entangling FAD can completely eliminate entanglement as stated by ISSF. However this mortality rate only covers the deaths caused by entanglement and does not take into account the sharks that can still be caught in the purse seine net set around a FAD.

A FAD, regardless of the design, attracts fish species (both target and non-target) which then gather around the fish aggregating device. In many cases, this results in a purse seine net catching non-target species after casting its net over the area. When asked by Atuna on this problem that can occur when using non-entangling FADs, ISSF acknowledged that it is a “separate issue” and says the type of FAD is not relevant when the sharks end up on the deck of a fishing vessel.

There is no evidence to indicate the non-target species are less likely to be caught by the purse seine net using non entangling FADs – only that they have a lower risk of direct mortality from the FAD netting. In regards to the bycatch caught and brought on deck, ISSF recommends fishermen use its “best practices” which consists of “correct handling techniques” of the shark and a “speedy release”. Using this method, ISSF has found this can reduce mortality by 15-20 percent.

ISSF tells Atuna “it should be noted that this technique works for catches from free school sets as well, which also catches sharks”. While this is true, free school fishing does not use FADs and thus does not attract as much bycatch as FAD fishing. The Foundation acknowledges this and states, “shifting part of the effort from FADs to free school will reduce shark mortality to varying degrees depending on the magnitude of the shift”.

Due to the lack of further research on the effectiveness of non-entangling FADs in preventing non-target species from being caught in purse seine tuna fishing, it remains unclear as to how efficient they really are in reducing bycatch.