World Tuna Day 2023 - how seabird safe is the tuna we eat?

Tuna fisheries are among the largest and most widespread fisheries globally, and their operations can have a significant impact on seabird populations, as well as other vulnerable marine animals like whales, dolphins, sharks, and sea turtles. On World Tuna Day 2023 (2nd May), we are unpacking the sustainability of tuna and asking our team, how seabird safe is the tuna we eat? And to what extent does the Marine Stewardship Council’s recently released new certification Standard go towards reducing impacts on seabirds? Bernadette Butfield, International Marine Conservation Officer, dives into the details.

We are all increasingly aware of the declining health of the ocean, largely driven by human activities such as pollution, overfishing, and climate change. Such impacts are not only degrading marine ecosystems but threatening the seabird populations that rely on the ocean for their survival. Many of us know and love seabird species for their natural charisma and impress, but this group of birds are among the most threatened. With more than 50% of seabird species in decline, urgent action is needed to protect them.

Tokyo tuna market. © Stephanie Borrelle/BirdLife International. 

Bycatch – a real threat to seabirds
One of the most significant threats to seabirds is the incidental capture in fishing operations, also known as bycatch.

Looking at tuna fisheries specifically - one of the main fishing gears used is longlines, and it is one of the key causes of seabird bycatch. A longline consists of a main line with thousands of baited hooks attached to it on secondary or “branch lines”.

When longlines are deployed, the hooks on the end of the branch lines sink slowly from the sea surface to a depth between roughly 100 and 400 m and the entire longline can span up to 100 km.

Seabirds, such as albatrosses and petrels, have an incredible sense of smell and can smell bait from up to 30 km away. As baited hooks sink, they remain within diving range of many seabirds for several minutes, creating a high risk of entanglement and drowning.

Indeed, it is estimated that at least 160,000 and potentially more than 320,000 seabirds are killed in longline fisheries across the globe every year. Albatrosses have been heavily impacted by tuna longline fisheries, with some species experiencing population declines of up to 80% in recent decades.

Over 50% of seabird species, including the Wandering Albatross, are experiencing population declines. © Stephanie Prince. 

Making fishing lines safer for seabirds
Not all is lost though. There are simple and effective measures that can be taken to reduce the impact of tuna fisheries on seabirds, including:

· Bird-scaring lines: these are ropes with streamers that are attached to fishing vessels to create a visual barrier and deter seabirds from approaching the fishing gear.
· Weighted lines: which increase the sink rate of hooks, reducing the time they are available to seabirds.
· Night-setting: many seabirds are less active at night, so setting lines at night can help to reduce interactions.
· Hook-shielding devices: these encapsulate the hook until it sinks beyond the dive depth of most seabirds.

Our work has shown that use of these seabird “bycatch mitigation” measures can reduce seabird deaths by as much as 98%.

Working with tuna fisheries to implement and deploy the most effective measures is essential for seabird conservation, as these fisheries operate in some of the most important areas for seabirds.

Bird-scaring lines create a visual barrier and deter seabirds from approaching the fishing gear © Dimas Gianuca.

Setting standards for sustainable fishing practices
You might have seen the Marine Stewardship Council’s distinctive blue tick logo on packaging as you scan the supermarket shelves – let’s unpack what certification means for you and for seabirds.

The Marine Stewardship Council (MSC) is an independent organisation that sets standards for sustainable fishing practices and certifies fisheries that meet those standards, based on three core principles: sustainable fish stocks, minimising environmental impact, and effective management.

Tuna fisheries certified by the MSC have been through a process of assessment against set criteria and met thresholds that indicate they are fishing in a way that does not compromise the health of the target species, while also minimising harm to the marine environment and ensuring effective management practices are in place.

In some fisheries, obtaining MSC certification has been an important factor toward the adoption of seabird safe measures. In South Africa, Namibia and Argentina the process of certification with MSC has required the assessment of impacts on bycatch species. In each case this has permitted our Albatross Task Force to work to quantify the issue, leading to a better understanding of the scale of the impact. This process has led to the adoption of seabird conservation regulations that require the use of mitigation measures, and effective monitoring to ensure the measures are used by industry.

What are the benefits of the new MSC Standard for seabirds?
The Marine Stewardship Council has recently released a new version of its certification Standard, with an enhanced focus on the conservation of Endangered, Threatened, and Protected species.

The new Standard further strengthens the MSC approach towards achieving sustainably certified fisheries and includes specific benefits for seabirds. It requires fisheries to:

1. Protect vulnerable species by demonstrating that the fishing activity does not lead to the decline of the populations of Endangered, Threatened or Protected species.
2. Reduce bycatch using "best-practice" seabird bycatch mitigation techniques and report any bycatch incidents.
3. Increase transparency and traceability through improved documentation to ensure that the seafood supply chain is transparent and accountable. This helps to prevent illegal, unreported, and unregulated fishing, which can contribute to overfishing and harm to Endangered, Threatened or Protected species.
4. Collaborate with stakeholders to identify and address threats to Endangered, Threatened or Protected species. This collaborative approach helps to ensure that the best available science and information is used to inform management decisions and practices.
5. Improve monitoring and reporting to better understand the effectiveness of their mitigation measures and adjust as needed to reduce bycatch.

While the certification process provides a useful indication of a fishery's practices, it does not guarantee that every individual fish caught from that fishery is sustainable.

Tuna sourced from MSC certified fisheries is likely a more sustainable option for consumers, but several factors limit our confidence in the levels of seabird bycatch associated with certified tuna fisheries.

So what does this all mean for making fisheries safer for seabirds? As my colleague Oli Yates explains, the new measures are a step in the right direction, however: “We are concerned about the time it will take for fisheries, particularly those fishing for tuna, to effectively implement the new Standard. It could be several years before fisheries certified under the MSC label effectively implement the measures required to protect seabirds, marine mammals and sharks. For many seabird species like the Antipodean Albatross, immediate action is urgently needed to reverse the plight of this species.”

We are working closely with the MSC and other environmental organisations to provide input on how to promote increased action to reduce the impacts on seabird species around the world.

So, what can you do?
While MSC certification is an indicator of sustainability, it is important to note that certification does not guarantee that a seafood product is completely free from bycatch. The MSC's standards are better than other certification schemes, but they cannot account for all the factors that may affect the sustainability of a fishery or the level of bycatch it generates and there are delays in the process.

If you are concerned about the sustainability of the tuna that you buy, then look for the MSC label on packaging to ensure that it comes from a certified fishery. You could also research the specific fishery and company that produced the tuna to get a better understanding of the environmental and social practices involved in its production. If in doubt, avoid buying tuna caught on longlines as the risk of seabird bycatch is high. Pole and line caught tuna has an inherently lower risk to seabirds and other vulnerable animals.

The decline of seabird populations is a major conservation challenge, but by engaging with tuna fisheries to implement seabird safe measures we are working to address this issue so that seabirds can recover from population declines and thrive as part of a healthy marine ecosystem for generations to come.

By engaging with tuna fisheries to implement seabird safe measures we are working to address seabird population declines © Oli Yates/RSPB.

Continue reading
Find out more about our work on seabirds and bycatch:
• A view from the waves – how we’re working with retailers to make seafood safer for seabirds
• The mighty Pacific: how the RSPB is working with partners in Japan and Taiwan to reduce albatross deaths in High Seas fisheries
• Bycatch
• Albatross Task Force

Want our blogs emailed to you automatically? Click the cog in the top right of this page and select 'turn blog notifications on' (if you have an RSPB blog account) or 'subscribe by email'.