case study

Monitoring fishing activity on tropical tuna vessels: electronic monitoring versus onboard observers

In 2011, Spanish purse seiner Playa de Bakio became the world’s first tropical tuna vessel to test the latest in electronic monitoring technology. Equipped with both a CCTV-based monitoring system and onboard observers, the test vessel enabled researchers to compare the advantages and challenges of each, and to ultimately determine whether an automated monitoring system could serve as a viable alternative to onboard observers.


In the quest to eliminate illegal, unreported, and unregulated fishing, onboard monitoring—either human observers or automated systems—is a powerful tool. As fisheries and industry regulators move to incorporate monitoring into their fleets, automated monitoring systems are increasingly viewed as a comparable alternative to traditional observers, particularly in instances when a human observer would be impractical for logistical, safety, or financial reasons. But can a camera–based system actually provide a comparable level of service on a large pelagic fishing vessel? In 2011, the International Seafood Sustainability Foundation (ISSF) invited Archipelago Marine Research to help find out.

The goal of this study was to determine the effectiveness of electronic monitoring systems on tropical tuna purse seine vessels operating in the Atlantic, Indian, and Pacific Oceans. Over the course of several trips (on up to three vessels), the team would compare data from onboard human observers with data gathered by electronic monitoring equipment to determine the accuracy of each method (specifically when documenting set location, type of fishing, total tuna catch by species, and the amount of bycatch).

Equipping the vessels

Purse seiner Playa de Bakio, part of a fleet owned by the Spanish–based PEVASA group, was the first tropical tuna vessel to test the electronic monitoring technology. After experts from Archipelago Marine Research installed the EM Observe™ monitoring system, ISSF researchers joined the vessel crew on three fishing trips, monitoring a total of 61 separate fishing events.

EM Observe monitoring system: tuna seine

EM Observe monitoring system: tuna seine

Incorporating satellite modem, hydraulic sensor, and GPS receiver, the Archipelago system was configured to cover as much of fishing activity as possible, using four cameras above deck (to provide two views from the port side of the vessel and two views of the deck activity), along with three more cameras below deck (to monitor the conveyor belt and discard handling areas).

EM-viewsThroughout the trip, the system delivered hourly updates via satellite, reporting vessel position, fishing activity, and other relevant information. Once the vessel returned to port, any portion of the logged data was available for review in order to help evaluate fishing activity.

In early 2012, two more vessels were added to the trial. As part of the ISSF #BycatchProject, the Torre Giulia was equipped to monitor fishing activity in the Indian Ocean, and the Cape Finisterre participated as its counterpart in the Western Pacific. For comparison, the system set up, number of trips, and number of sets was similar for all three vessels, with cameras typically set to monitor the stern deck area (where fish were brought aboard), and below deck (where fish were moved to the storage wells). Approximately 18 sets were made during each vessel’s cruise.

Promising results

The results were extremely promising for electronic monitoring as a viable alternative: 95% sensor data success, 99% image data success, all sets were detected, and the electronic equipment correctly identified free school and FAD sets 98% of the time. The total catch estimate provided by the electronic equipment was also accurate, with no significant difference between the estimates provided by observers and by the electronic monitoring equipment.

In conclusion

Overall these studies indicated that when done properly, electronic monitoring can help regulators, scientists, and environmental activists to access information about what’s been caught, how it’s caught, and what happens to the catch once it’s onboard the vessel.

The studies also demonstrated that electronic monitoring is a valuable tool for onboard monitoring, ensuring coverage is always possible, even in situations where an onboard human observer would not be a practical, or safe, option. Although more work was in order to accurately determine the composition of tuna catch and small bycatch species, this research clearly indicated that regular third–party observation can become a best practice for the industry as a whole.

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