Data from the IOTC shows the volume of yellowfin caught on FADs more than doubled over a decade, while free school tonnages have dropped. The catch of skipjack tuna in the Indian Ocean also shows a similar trend. This increase in FAD caught tuna further reinforces the need for the FAD measures adopted by the RFMO last year.
In 2007, just over 43,770 tons of yellowfin was caught by purse seiners using FADs. Almost 10 years later in 2016, as the devices became more advanced, this figure significantly went up to 98,659 tons.
It should be noted, seiners using FADs mostly target skipjack tuna, which would indicate most of this catch is in fact bycatch in the form of juvenile yellowfin. This massive rise in tonnage was reflected in the last stock assessment in 2016 which rated IO yellowfin as overfished. As a consequence, the IOTC was forced to implement a regulation that cut purse seine yellowfin landings by 15 percent.
On the other hand, skipjack in the Indian Ocean is still rated green, however, there have also been concerns about the status of this species. It also follows a similar trend to yellowfin and in 2016, 174,048 M/T was caught by purse seine associated (FAD) sets in comparison to a tonnage of 108,252 that was caught in 2007 in the same way.
Following an assessment that showed a decline in skipjack stock abundance, at the end of 2017, the IOTC put in place a skipjack catch limit for the first time. However, the quota for the species, which is at around 470,000 tons, is in fact higher than the total landings made by purse seiners in 2016 – making it debatable as to how effective this limit can be.
Other measures implemented by the IOTC last year include reducing the number of supply vessels (small boats that deploy and maintain FADs) working alongside seiners. The number of drifting FADs deployed per vessel per year was also limited to 350, down from 425. The increased focus on FAD management by the IOTC suggests cutting down on the use of these devices can lessen the pressure on yellowfin stock.
Despite the RFMO and some NGOs encouraging fishing firms to slow down their FAD use, purse seiners fishing on free schools in the IO, which is seen as a more sustainable method than FAD fishing, have not been catching greater volumes over the years. Although the tonnages caught on free schools has varied, there has been an overall decline.
In 2007, 23,568 tons of skipjack was caught on free school sets and only just over 6,500 was caught in 2016. A drop, although by a lower tonnage, is also seen in yellowfin statistics.
Some industry sources have said catching free schools in the IO is difficult because there is less schooling of skipjack than other ocean regions. Yet, a representative from the IOTC tells Atuna that the “vast majority (if not all) of skipjack are found in schools in the Indian Ocean”. They also state the same can be said about yellowfin tuna.
Nonetheless, the IOTC members will know the outcome of the recent conservation measures in November, following a stock assessment on both yellowfin and skipjack. The results of the assessment are likely to majorly impact how the members proceed in keeping these vital tuna species at a sustainable level.