Scottish Mackerel Factories, Norwegian Researchers Track Fish Health via RFID

By Claire Swedberg

The LF system, provided by RFID Solutions, is enabling researchers in Norway and factories on both coasts of the North Sea to track populations of mackerel being caught.


The Norwegian Institute of Marine Research (IMR) is managing populations of mackerel, as well as some spawning herring in parts of the Northeast Atlantic, using an RFID-based program that tracks the number of fish and their size and weight as they are caught and harvested in Scandinavia and the British Isles.

Recently, fish producers in Scotland have joined the growing number of participants in the program to better understand mackerel populations on both sides of the Northeastern Atlantic. Nearly every Scottish mackerel processing factory is now employing low-frequency (LF) RFID readers to identify tagged fish before processing begins, joining factories in Iceland and at the Faroe Islands that were already doing so. Approximately 160,000 mackerel have been tagged to date. In 2016, 800 of those tagged fish were detected at all participating factories.

IMR’s Aril Slotte

The IMR project results thus far indicate that mackerel populations are healthy—a critical result, since the mackerel serves one of the primary seafood sources for Scandinavia, as well as for Great Britain. Norway funds the IMR project at a rate of approximately 4 million Norwegian krone a year ($478,000), while the goal has been to see other nations in the region begin including the technology at their own factories as well, to both access and share data.

The solution consists of LF RFID tags embedded in fish, with readers deployed at factories. The RFID-based data is gathered in the global fish species database known as FishBase. The system—including LF RFID tags, readers and specialized antennas—is provided by Norway’s RFID Solutions. The software that interprets the collected read data and forwards it to the FishBase system is provided by Smart Sea System. The collected data helps IMR, better understand—and thus manage—the mackerel population.

The IMR is a Norwegian national research institute owned by the Ministry of Fisheries and Coastal Affairs. Its task is to advise industrial and government organizations regarding the ecosystems of the Barents Sea, the Norwegian Sea and the North Sea.

Mackerel serve an important ecological role in various parts of the Northeast Atlantic, both on the coastlines and at sea. They also serve as a valuable stock for the fish market in Scandinavia and in Scotland. Financially, it is considered the most valuable stock in the Atlantic Ocean. Therefore, the management of mackerel has been a key effort in Norway for decades.

The tagging of mackerel dates back nearly half a century, explains Aril Slotte, IMR’s lead scientist in the RFID-tagging program. In 1968, scientists at the institute first started injecting metal tags into the muscular tissue of fish in spawning grounds west of Ireland and Scotland. Each tag had a unique ID number etched into it, and the fish were then released.

To identify tagged fish once they were caught, fish factories used metal detectors. If the detectors identified a tagged fish, it was removed from the catch and transported to an IMR lab, at which the tag was extracted and its visual ID number was input to link to biological data, such as the fish’s length, weight and age. Locating those tags and viewing their IDs was a large and cumbersome process, however.

With the implementation of the RFID system in 2011, Slotte says, this process became automatic. Researchers inject 134.2 kHz RFID tags that measure 3.85 millimeters by 23 millimeters (0.15 inch by 0.9 inch) into the muscle of young fish. The IMR has tagged about 160,000 mackerel in this way thus far.

At each participating factory where the caught fish are processed before being shipped to retailers, an RFID reader and antenna have been installed at the assembly line on which processing begins. Most readers are mounted on the main conveyor belt where fish are sorted into sized groups, Slotte says. In Iceland, the reader is installed at the pipeline that pumps fish from the vessel into the factory. In the latter case, a ring antenna is installed around the pipeline.

Readers transmit data directly back to the centralized software in Norway. The RFID antennas at conveyors and pipe lines can capture reads as more than 50,000 kilograms (55 tons) of fish pass through the portals. In total, 300,000 metric tons of mackerel are screened by the antennas each year.

Data is collected at the Institute of Marine Research’s central database in Bergen, Norway. The platform includes Web-based software that captures all of the data biased on tag reads, as well as the system’s status at each factory. The software provides analysis based on biological information, such as the date of capture and the abundance of fish, which can be used to better manage quotas for the fisheries.

The IMR has been using the data received not only to gain information in real time, but also to view historical patterns. There are some statistical calculations worked into the results, Slotte explains. For instance, he says, if researchers were to release 1,000 tagged fish to the sea and let them mix, then catch a million fish, “If you scan the catch through the RFID antenna-reader systems and get one tagged fish recaptured, then you expect a thousand times more fish in the sea than the tagged population of fish.” Therefore, he says, “the estimate of abundance is one billion fish.”

Introducing RFID to the system not only reduces labor time on the part of researchers and factory workers, Slotte notes, but also better ensures that tags will be identified. In fact, with the introduction of RFID, the rate of tagged fish reads increased tenfold. The technology was initially tested at a Norwegian factory in 2011, then was installed the following year at eight additional factories. Since 2014, the system has expanded to another eight factories in Scotland, Iceland and the Faroe Islands.

All participating factories are given access to the read data, but only to information related to recaptures. As such, they can follow recaptures as they occur, but cannot edit or access analysis of the data.

Since the RFID system was taken live, the IMR has begun tagging Norwegian spring-spawning herring. That effort, Slotte says, will require RFID infrastructure at factories dedicated to herring. The agency is currently in conversations with those factories, he adds, and is also working on the necessary changes to the software to accommodate the new fish variety.

In the future, Slotte says, salmon that the IMR tags as smolts (juveniles) in North Sea tributaries may also be recaptured in these systems. A growing number of countries have shown an interest in participating in the program, he reports.