Yellowfin tuna catches must be cut by 30 per cent to save the stock

February 23, 2022 by Blue Marine Foundation


The Indian Ocean Tuna Commission (IOTC) has today published its Scientific Committee report, detailing the results of the long-awaited yellowfin tuna stock assessment.  The results show that, despite having had a stock recovery plan in place for five years, the stock is still overfished and subject to continued overfishing.  A substantial catch reduction of at least 30 per cent is now essential to save the Indian Ocean yellowfin tuna stock.

The EU’s industrial distant-water purse seine fleet is the largest contributor to overfishing and has been for as long as the stock has been overfished.  Other IOTC member states like Oman have compounded the problem by dramatically increasing their catch since 2019.

Based on projections in the Scientific Committee report and the results of the new stock assessment – the first of its kind since 2018 – a sustained 30 per cent catch reduction is necessary to bring about a reasonable likelihood of stock recovery by 2030.  This reduction would necessitate a new catch limit of roughly 301,000 tonnes – almost 130,000 tonnes less than was caught in 2020.

In recent years, there has been significant uncertainty surrounding the management advice issued by the IOTC, due to “critical errors” within the Scientific Committee’s stock projections.  These errors prevented any new management advice being issued in 2021.  In the face of such uncertainty, a precautionary approach should have led to IOTC contracting parties significantly reducing their fishing pressure.  Instead, another revision of the stock rebuilding plan was adopted in June 2021 which is unlikely to achieve the recovery of yellowfin tuna in the Indian Ocean.

IOTC contracting parties will have the opportunity to rectify this later this year at the 26th Session of the IOTC in May.  As highlighted at COP26 during the EU Ocean Day, the ocean plays a crucial role in mitigating climate change – it produces 50 per cent of the earth’s oxygen and absorbs excess heat, while locking away and storing carbon.  Damaging practices like overfishing destabilise the essential ecosystems that support all life on earth.

Callum Roberts, Professor of Marine Conservation at the University of Exeter and Chief Scientific Adviser at Blue Marine Foundation, said: “Now that we have a new, more reliable stock assessment for Indian Ocean yellowfin tuna, it is clear that a catch reduction of at least 30 per cent from 2020 levels is needed to be confident in our chances of stock recovery. A 50-50 chance of saving the stock is not good enough – no better than a coin flip on yellowfin recovery. Healthy oceans need healthy fish populations.”

In 2015, the IOTC Scientific Committee recommended that catches be reduced by 20 per cent to allow the stock to recover[1]. Since then, catches have increased by more than 25,000 tonnes, totalling more than 430,000 tonnes in 2020[2].  Concerningly, the new stock assessment has determined the maximum sustainable yield (MSY) of the yellowfin stock to be some 54,000 tonnes less than previously thought, highlighting the growing impact of overfishing.

Umair Shahid, Indian Ocean Tuna Manager at WWF, said: “The IOTC assessment quantifies just what has been lost while members delayed action by blaming a ‘lack of science.’ Now it is crystal clear; strict conservation and management measures are urgently needed to allow Indian Ocean yellowfin to recover within the next decade. This is the only way parties of the IOTC can meet their commitments to sustainable development and biodiversity goals.”

Martin Purves, Managing Director of IPNLF, said: “Now that the science is clear and we know that catches need to be reduced by almost a third, the only remaining barrier to effective conservation is political will.  Decision makers must put aside greed and short-term gain to ensure the long-term survival of this important stock. The food security and livelihoods of coastal communities should always surpass the interests of profit-driven operations by distant water fishing nations”.

We call on the EU to uphold its commitments on combating biodiversity loss and climate change at a global level, pledging to reduce tuna catches in the Indian Ocean region.

[1] IOTC. 2015. Report of the 18th Session of the IOTC Scientific Committee.

[2] IOTC. Best scientific estimates of nominal catch data for IOTC species (used for stock assessment purposes and fully disaggregated by species and gear). Available:


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