Bycatch in tuna fishing refers to the unintentional capture of non-target marine species during fishing operations. This includes dolphins, sharks, sea turtles, and other fish species caught alongside tuna. Bycatch creates significant sustainability challenges for the tuna industry, threatening marine biodiversity and raising concerns about fishing practices among consumers, retailers, and regulatory bodies worldwide.
What exactly is bycatch and why does it matter in tuna fishing?
Bycatch occurs when fishing gear captures marine animals other than the intended tuna species. Common accidental bycatch includes sharks, sea turtles, billfish, dolphins, and juvenile tuna that have not yet reached reproductive maturity.
The scale of this issue varies significantly depending on fishing methods and locations. Some tuna fishing operations may accidentally catch several non-target species for every tonnage of tuna landed. This matters because many bycatch species play important roles in marine ecosystems, and some face population declines.
For the tuna industry, bycatch creates multiple challenges. Consumers increasingly demand sustainable seafood options, and retailers often require proof of responsible fishing practices. Companies that cannot demonstrate low bycatch rates may face restricted market access, reduced consumer trust, and potential regulatory scrutiny.
How does bycatch impact ocean ecosystems and marine biodiversity?
Removing non-target species from ocean ecosystems disrupts natural food webs and population dynamics. When predators like sharks are caught as bycatch, their prey species may increase unchecked, potentially affecting the entire marine food chain.
Certain shark species, sea turtles, and dolphins face particular vulnerability because they reproduce slowly and take years to reach maturity. Even relatively small amounts of bycatch can significantly impact these populations over time. Very few species caught as bycatch in tuna operations are threatened or endangered, however, making any additional mortality concerning from a conservation perspective.
The cumulative effect across multiple fishing fleets and ocean regions can be substantial. When vessels consistently remove the same non-target species from specific areas, local ecosystem balance may shift, affecting fish populations that tuna depend on for food.
What fishing methods create the most bycatch in tuna operations?
Different tuna fishing methods produce varying levels of bycatch:
- Longline fishing – Typically produces the highest bycatch rates, as lines with hundreds or thousands of hooks attract sharks, sea turtles, and seabirds along with tuna
- Purse seining around FADs – Can generate significant bycatch when nets are set around fish aggregating devices, which attract juvenile fish and other marine species alongside tuna
- Free-school purse seining – Generally produces lower bycatch rates when targeting free-swimming tuna schools rather than FAD-associated fish
- Pole-and-line fishing – Creates the least bycatch because operators can selectively catch individual fish, allowing immediate release of non-target species
While pole-and-line fishing minimizes bycatch, it typically yields lower tuna volumes and requires more labor and fuel. This trade-off between efficiency and bycatch reduction influences operational decisions across the industry.
How can tuna fishing companies reduce bycatch without losing profitability?
Companies can implement several cost-effective strategies to minimize bycatch while maintaining viable operations:
- Equipment modifications – Using circle hooks instead of J-hooks in longline fishing reduces sea turtle and shark catches without significantly affecting tuna capture rates
- Strategic timing and location adjustments – Avoiding areas with high concentrations of vulnerable species during sensitive periods can substantially reduce unwanted catches
- Technology integration – FAD monitoring systems help purse seine operators distinguish between tuna schools and mixed-species groups before setting nets
- Enhanced species identification – Investment in sonar and underwater cameras improves pre-catch accuracy
- Crew training programs – Proper release techniques for accidentally caught animals reduce mortality rates without requiring major equipment changes
Many sustainable tuna fishing operations use real-time data to identify optimal fishing locations, combining multiple techniques to achieve measurable reductions in non-target species capture while maintaining profitability.
How SmarTuna helps with bycatch monitoring and sustainable fishing verification
SmarTuna’s digital traceability platform captures real-time vessel activity data that enables comprehensive monitoring of fishing practices, including bycatch reduction efforts. The system tracks fishing methods, locations, and timing to verify sustainable practices from the moment fishing operations begin.
The platform provides several key capabilities for bycatch monitoring:
- Real-time vessel tracking – Satellite VMS and AIS technology verify fishing locations and methods to ensure compliance with sustainable fishing zones and practices
- Observer data integration – Review of observer reports and electronic monitoring data that document bycatch incidents and species interactions. Observer reports are not made public.
- Automated compliance verification – Cross-referencing against sustainability databases and certification standards to validate fishing practices in real-time
- Digital documentation system – Comprehensive recording of fishing practices that supports sustainability claims with verifiable, tamper-proof evidence
SmarTuna enables companies to demonstrate their commitment to reducing bycatch through documented proof rather than unverified claims, strengthening relationships with retailers, consumers, and regulatory bodies while supporting long-term supply chain sustainability.
Ready to verify your sustainable fishing practices? Contact SmarTuna to learn how comprehensive traceability can strengthen your sustainability credentials and reduce supply chain risks.
