Statement in advance of the 28th Session of the IOTC

May 02, 2024


Blue Marine Foundation calls for a credible stock rebuilding plan for yellowfin tuna and a moratorium on drifting fish aggregating devices in the Indian Ocean

There is an overfishing crisis in the Indian Ocean. Total tropical tuna catches in 2022 were the second highest ever recorded, despite clear evidence that two of the three species – yellowfin tuna and bigeye tuna – are overfished. In addition, the catch limit put in place for skipjack tuna has been ignored every year since it was introduced, with 2022 skipjack catches being 30% higher than the agreed catch limit[1].

By 2025, yellowfin tuna in the Indian Ocean will have been overfished for a decade. A stock assessment was last undertaken for yellowfin in 2021 and showed that a 30% reduction in catches from 2020 levels is needed in order to bring about the likely recovery of the stock by 2030. This would necessitate a catch limit of 301,000 tonnes[2]. However, given that catches in 2021 and 2022 have vastly exceeded this limit, it is likely that the health of the yellowfin tuna stock has declined even further, and that the reduction now needed to recover the stock by 2030 is even higher than previously thought.

Of the 1,187,565 tonnes of tropical tuna caught in the Indian Ocean in 2022, the EU-owned industrial purse seine fleet caught 377,042 tonnes – almost a third of the entire catch. This was achieved largely through the use of harmful drifting fish aggregating devices (dFADs). The IOTC recently noted that that the dFAD-associated fishery accounts for 80-85% of catches by purse seine vessels in the region[3].

Recent science has shown that, short of closing the entire Indian Ocean tuna fishery for two or three months – something that would not be possible for coastal communities that depend on fishing for food security and livelihoods – the most impactful measure would be a three-month, ocean-wide closure of the FAD-associated purse seine fishery. Indeed, a paper presented at the last IOTC Working Group on FADs analysed fleet-specific closures and found that closing only the FAD-associated purse seine fishery would produce the largest positive effect on the stock status, compared to other fisheries[4].

Many endangered, threatened and protected species fall victim to dFADs, either as bycatch or through entanglement, with a recent study estimating that at least 100,000 silky sharks (which are listed as “vulnerable” on the IUCN Red List) end up as bycatch in the Indian Ocean purse seine industry alone each year[5]. The use of dFADs has also contributed significantly to the over-exploitation of yellowfin and bigeye tuna in the Indian Ocean, with 97% of yellowfin tuna caught by purse seine vessels around drifting FADs in the Indian Ocean shown to be juveniles[6], further impacting the health of these already-overfished stocks.

Blue Marine Foundation supported the adoption of IOTC Resolution 23/02 on drifting FADs which was voted in by a two-thirds majority in February 2023 and introduced a drifting FAD registry, a reduction in the number of drifting FADs permitted per vessel, and most importantly, a 72-day closure period for drifting FADs in the Indian Ocean[7]. The EU chose to object to the resolution[8], despite supporting similar measures in other oceans where its fleet does not fish as much. This objection has been challenged by Blue Marine and BLOOM as it is in breach of EU law and, in particular, in breach of the precautionary principle[9]. Blue Marine understands that, should the European Commission withdraw its objection on grounds of illegality, the total number of objections will drop below the threshold and Resolution 23/02 will become binding on the EU fleet.

The European Union has repeatedly shown that it has no interest in effectively managing its industrial, distant-water tuna purse seine fleet. The same is true for Seychelles and Mauritius, both of which allow EU-owned purse seine vessels to fly their flags of convenience, utilise their tuna quota and pollute their waters with thousands of destructive dFADs[10].

Therefore, in addition to calling for the adoption of a new stock rebuilding plan for yellowfin tuna that implements a 30% reduction in catch from 2020 levels, Blue Marine Foundation is calling for a moratorium on the use of drifting FADs in the Indian Ocean until the European Union and its Spanish and French-owned purse seine fleets take responsibility for the destruction caused by their dFADs and implement responsible, legal, sustainable fishing practices and management measures.

Cover image: Alex Hofford/Greenpeace

[1] IOTC (2023). Report of the 26th Session of the IOTC Scientific Committee. Available:

[2] IOTC (2021). Report of the 24th Session of the IOTC Scientific Committee. Available:

[3] IOTC (2023). Report of the 5th IOTC Working Group on FADs. Available:

[4] G. M. Correa, G. Merino, J. Santiago, A. Urtizberea (2023). Responses of tuna stocks to temporal closures in the Indian Ocean. Available:

[5] I Ziegler (2022). Assessing the impact of drifting FADs on silky shark mortality in the Indian Ocean. Available:

[6] Global Tuna Alliance (2021). Sustainability of yellowfin tuna (Thunnus albacares) fisheries in the Indian Ocean, with a special focus on juvenile catches. Available:

[7] See:

[8] See:

[9] See:

[10] See:

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