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Watch this animated video to get a clear understanding of the problem.


The European Tracking Network aims to deliver state of the art and relevant science utilizing a global network of equipment and scientists that work together to achieve common goals. As such, ETN requires a completely compatible telemetry system that allows for flexibility to operate tags and equipment produced by all the equipment manufacturers. This particularly important since the European animal telemetry community is highly diverse and using multiple telemetric approaches and equipment from several brands.

Some terminology

  • Tag protocol: A protocol is a set of unique tag IDs you have available. It is an R script that defines the IDs based on pulse position modulation (PPM).
  • PPM: Pulse position modulation. Tags transmit a series of pulses and each series of pulses defines a unique ID. This unique ID is encoded in the time intervals between the successive pulses.
  • Code map: A receiver will listen to a list of tag protocols. This list defines the code map.

Recent history in acoustic telemetry

Until recently, equipment manufacturers did not have formal agreements regarding tag protocols, ID allocation and tag serial numbers. However, there was a ‘gentlemen’s agreement’ in place with block ID allocation per brand (thus each manufacturer had a block of codes they could use). As there were only a few tag protocols operational (R64K, S256, R04K, R256) that were used by the different manufacturers (see table 1), and with the gentlemen’s agreement, the situation was working well.

In recent years however, one of the major manufacturers of acoustic telemetry equipment has introduced a new encrypted operating system for their tags and receivers (see table 1) and has removed the other protocols. Importantly, as tags are encrypted, and receivers do not register the original code sets, this means that:

  • Tags from this manufacturer will not transmit to receivers from other manufacturers;
  • Receivers from this manufacturer will not detect tags from other manufacturers;
  • Tags from this manufacturer may transmit different IDs to receivers from other manufacturers;
  • Researchers will not be able to “mix and match” telemetry equipment from different manufacturers so their needs are best addressed, and may be tied to a single operating system.

Problems related to the current situation

The reliance on a single manufacturer could stifle innovation within the telemetry community and restrict the scope, type and flexibility of research. This would also lead to reduced competition, resulting in increased unit prices, and researchers spending more on equipment. In Europe, the operation of and reliance on a single manufacturers system would not meet the requirements of EU competition legislation, and prevent organization bidding for European funds. This would also operate at a national government level.

In essence, this means that buying into this new encrypted operating system will lead to acoustic systems being incompatible across Europe. The result will inevitably be that the European Tracking Network will fail its primary goal of broad scale collaboration, and the important work we do will come to an end.

As a network, we believe this new system would have major consequences for future research by compromising collaborations between acoustic telemetry users and a potential loss of valuable data. Existing long-term research projects on large and wide-ranging pelagic species could suffer if existing global telemetry networks differed in their implementation of the new operating system. For instance, large pelagic fish – for example tuna tagged in Europe with multi-year tags operating on the existing system – may not be detected by colleagues operating the new non-compatible system in North America. Species with not yet known large migrations patterns will also go undiscovered.

The network therefore asks that European acoustic telemetry users take this into consideration when buying equipment to ensure the future of scientific research on aquatic animals in Europe.

Solution to the current situation

To move forward towards a much-needed Pan-European collaborative network that could provide relevant information in support of decision-making processes related to conservation and management, compatibility between brands and agreements on transmission protocols and ID allocation are imperative. Therefore, researchers and industry need to work in close proximity to foster technological advancements in both optimisation and developments of biotelemetry.

As a medium-term solution, the ETN has worked on the development of new open tag protocols. Together with Thelma Biotel, Sonotronics and Lotek, we have over the past year developed robust and energy-efficient transmission protocols aimed for the aquatic research community. The two initial versions of the new open protocols coding (OPC) have been named OPi and OPs, for ID and sensor tags respectively. OPi supports over 1 million unique IDs and OPs supports over 64 000 unique IDs with up to 4096 data points resolution. Both protocols are short and effective to reduce issues with transmission collisions. The protocols will be available for all interested manufacturers and researchers and compatible with the most common existing and new equipment. Open protocols encourage healthy and fair competition, flexibility in choosing the best equipment, service and price. Opening the infrastructure networks of acoustic telemetry to all manufacturers of different types of sensors and tags drives innovation, and boosts availability of new solutions for future research.

ETN is also working on a long term solution, but more of this will come at a later stage.

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