Purse seine fishing is a commercial fishing method that uses large circular nets to encircle schools of tuna swimming near the ocean’s surface. The net forms a wall around the fish, then closes at the bottom like a drawstring purse to trap the entire school. This technique is one of the most efficient ways to catch tuna that travel in groups, making it a dominant method in commercial tuna fishing operations worldwide.
What is purse seine fishing and how does it work?
Purse seine fishing operates through a systematic process that involves multiple vessels and specialized equipment working together to capture entire schools of fish:
- School detection and positioning – Fishing vessels locate tuna schools using sonar technology, helicopter spotting, or visual identification from the vessel’s crow’s nest
- Net deployment and encirclement – The main vessel releases one end of the massive net while circling the fish at high speed, with a smaller skiff boat holding the opposite end to complete the circle
- Purse closure activation – Steel rings threaded along the net’s bottom allow a cable to run through them, which when pulled tight closes the net like a drawstring bag
- Net retrieval and fish collection – The entire net structure is hauled aboard using powerful winches, bringing the trapped tuna with it
The net itself can stretch over a mile long and reach depths of several hundred feet, creating a vertical wall in the water that forms an inescapable enclosure. This purse closure system is what makes the technique so effective, as it prevents fish from escaping downward while the net is being retrieved, ensuring maximum catch efficiency for commercial operations.
Why do fishing companies choose purse seines for tuna?
Commercial fishing operations prefer purse seines for tuna fishing due to several operational and economic advantages that make this method highly profitable:
- High-volume catches – A single successful deployment can capture dozens of tons of tuna, significantly outperforming hook-and-line methods in terms of quantity
- Species-specific targeting – Tuna naturally form dense schools near the surface during feeding and migration, making them ideal candidates for seine net fishing
- Operational efficiency – Successful fishing operations can be completed in hours rather than days or weeks, reducing fuel consumption and crew costs
- Cost-effectiveness – The ability to capture large quantities quickly translates directly into higher profit margins in competitive global markets
These purse seine fishing techniques align perfectly with tuna behavior patterns, as these fish species exhibit predictable schooling behaviors that can be efficiently targeted. This combination of natural fish behavior and technological capability has made purse seining the dominant commercial method for tuna fishing worldwide, allowing companies to meet global demand while maintaining operational profitability.
What types of tuna are caught using purse seine methods?
Seine net fishing methods target specific tuna species based on their schooling behaviors and market value, with catch composition varying by ocean region and season:
- Skipjack tuna – Represents the largest global catch volume due to their dense surface schooling and active daylight feeding patterns
- Yellowfin tuna – Often caught in mixed schools with skipjack or around floating objects, commanding higher market prices despite lower abundance
- Bigeye tuna – Frequently associates with other tuna species near seamounts and FADs, valued for premium sashimi markets
- Regional variations – Pacific operations typically target mixed-species schools while Atlantic fishing focuses on seasonal migration concentrations
Skipjack tuna are particularly well-suited to purse seine fishing because they form large, dense schools near the surface and maintain high activity levels during daylight hours, making them easier to locate and encircle. The schooling patterns of these species create opportunities for efficient commercial fishing operations, with yellowfin and bigeye tuna often providing higher-value catches that improve the overall profitability of fishing trips.
How does purse seine fishing impact tuna sustainability?
Purse seine fishing presents both challenges and opportunities for tuna sustainability, with modern practices increasingly focused on addressing environmental concerns:
- Bycatch management – Gear modifications and selective fishing around FADs help reduce unintended captures of dolphins, juvenile tuna, and other species
- Quota compliance – Regional Fisheries Management Organizations establish science-based catch limits that are regularly updated to prevent overfishing
- Certification programs – MSC and ISSF standards provide frameworks for sustainable fishing practices with regular monitoring requirements
- Technology improvements – Advanced fish aggregating devices and monitoring systems enable more selective targeting of mature tuna schools
These sustainable tuna fishing practices represent a significant evolution from earlier purse seine operations, with the industry increasingly recognizing that long-term profitability depends on healthy fish populations. Modern certification programs and regulatory frameworks work together to ensure that purse seine fishing can continue meeting global demand while maintaining the ecological balance necessary for future tuna populations to thrive.
How SmarTuna helps with purse seine fishing traceability
SmarTuna provides comprehensive traceability for purse seine fishing operations by capturing real-time vessel data from the moment fishing begins. The platform uses satellite VMS and AIS tracking to monitor fishing vessel activities, ensuring complete visibility into where and how tuna are caught.
Key capabilities for purse seine traceability include:
- Real-time vessel monitoring – Satellite VMS and AIS tracking provide continuous oversight of fishing vessel movements and activities throughout operations
- Unique batch identification – Assignment of raw material IDs at port discharge creates direct links between each catch batch and verified origin data
- Regulatory compliance verification – Automated checking against 15+ databases including RFMO registries and IUU blacklists ensures legal compliance
- Sustainability certification integration – Seamless compatibility with MSC CoC and ISSF PVR systems supports verifiable sustainability claims
- Comprehensive documentation – Digital storage of vessel records, discharge volumes, and certification documents provides audit-ready traceability
Built on GS1-EPCIS standards and fully GDST compatible, SmarTuna enables seamless data exchange throughout the tuna supply chain while providing the transparency needed for modern seafood markets. This first-mile traceability approach transforms how purse seine operations demonstrate compliance and sustainability, creating verifiable documentation that reduces regulatory risks and supports premium market positioning for responsibly caught tuna.
Discover how SmarTuna transforms tuna supply chain transparency with comprehensive vessel-to-shelf traceability for your purse seine fishing operations.
