European Tracking Network for fish has reached over 500 million detections | Lifewatch regional portal

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European Tracking Network for fish has reached over 500 million detections

Added on 2021-10-27 11:39:42 by Tavernier, Annelies
In recent years, fish tracking technology has revolutionized our knowledge on fish migration and behaviour. Today, the European Tracking Network (ETN) integrates the European efforts of hundreds of users, dealing with thousands of tagged fish from a multitude of species. Within this LifeWatch initiative, 500 million detections so far have taught us a lot on fish species such as Atlantic bluefin tuna, European seabass and sturgeon.
There is a large and growing number of researchers using biotelemetry to study aquatic animals, such as fish, and answer management-related questions (stock management, impact of climate change, etc.). Large scale nationally and regionally managed fish tagging initiatives were implemented around the globe in recent years. The European Tracking Network (ETN) aims at getting collaborations in the field of aquatic animal tracking in Europe and ensuring a transition from a loosely-coordinated set of existing regional telemetry initiatives to an open, sustainable, efficient, and integrated pan-European biotelemetry network embedded in the international context.

In animal tracking research, electronic tags are attached (internally or externally) to the animal which allow to follow-up the movement behaviour of the animal. On land, GPS technology can be used, but in the aquatic environment one relies on other technologies as GPS signals don’t work under water. Different technologies are used here, but one of the most commonly applied technique is acoustic telemetry. This technology uses tags that emit a sound signal that is recognized by receivers placed at strategic locations. For more info on the technology and its applicability follow this YouTube link.

Today, ETN is celebrating its 500 million detections, with 8710 tags applied to 81 species. Biotelemetry has proven its value in research on all those species, often with a scope on pressing scientific as well as policy-driven questions. For vulnerable species such as the Atlantic Bluefin tuna for instance, biotelemetry enables the researchers to fine-tune their long-distance migration patterns in support of protective management plans. In the case of critically endangered species such as the European sturgeon, tagging is a crucial element in reintroduction programs. And for several species, including the European seabass, biotelemetry facilitates the study of a species’ migration and population structure beyond the individual stock level.

* Atlantic Bluefin tuna (Thunnus thynnus) are an emblematic endangered species. Built like torpedoes, this largest tuna lives up to forty years and weighs up to 700 kg, making them impressive top predators. Lack of knowledge about their biology and migration patterns has long hindered successful fisheries management plans. Despite having been widely studied, knowledge gaps still remain in the migration patterns of Atlantic bluefin tuna. Traditionally, it has been described that western Atlantic bluefin tuna travel from foraging areas to spawning grounds in the Gulf of Mexico in April–June, returning back to feeding grounds during the summer whereas the eastern stock migrates into the Mediterranean Sea in May–June to spawn, and then back to the North Atlantic. Thanks to tagging studies, trans-oceanic movements have been described, showing mixing of the two stocks. The recent coupling of the Canadian Ocean Tracking network (OTN) and ETN will further support and facilitate the follow-up of trans-Atlantic migration and dispersion of this and other fish species.

* European seabass (Dicentrarchus labrax) is a fast-moving demersal fish species that is fished both professionally and recreationally because of its high commercial value and iconic angling status. As they tolerate wide ranges of temperature and salinity, these opportunistic predators are found in a variety of coastal habitats, to which they can adapt their hunting strategy. Despite this, individual seabass seem to be bound to specific locations. Biotelemetry studies in different countries and waters found that seabass exhibit high residency to summer feeding grounds. Moreover, they often return to these same locations after their spawning migrations to warmer and deeper waters during winter. On the one hand, the seasonal migrations shape the spatial stock structure. On the other hand, the highly localized residency puts seabass at risk of local depletion. Investigating individual movement and migration patterns is therefore crucial to fisheries management.

* The European sturgeon (Acipenser sturio) is a long-lived fish with distinctive characteristics, such as an elongated, scaleless body armored with rows of bony plates. They can grow up to 6 meter in length and weigh 350 kilos. European sturgeons behave as anadromous bottom-feeders, migrating upstream to spawn, but spending most of their lives feeding in coastal areas and estuaries. They are well-known for their roe, processed into caviar. Historically, the European sturgeon occurred in all coastal waters and main river systems of northwest Europe. Today the European sturgeon is listed as critically endangered by the IUCN, due to a combination of habitat destruction, overfishing and pollution. Reintroduction programs, from the only remaining source population in the Gironde (France), have started in the Elbe (Germany) river in the 1990s. Recently, the Rhine (the Netherlands) is considered for a reintroduction, sourcing from the remaining populations. Tagging programs are crucial in monitoring the success of those reintroductions.

The ETN initiative is powered by LifeWatch Belgium through Flanders Marine Institute (VLIZ) and Research Institute for Nature and Forest (INBO), and supported by numerous partners throughout Europe. LifeWatch is a European infrastructure for biodiversity research. As a virtual laboratory consisting of observation stations, databases, web services and modelling tools installed across Europe, this network facilitates the generation, processing, integration and analysis of biodiversity data. Within this framework, LifeWatch Belgium is organizing a LifeWatch Biodiversity Day on ‘Biologging and camera trapping’, on 28 October 2021.

Visuals are available upon request:

Press contacts: Source Image: © Exeter University

European Tracking Network for fish has reached over 500  million detections


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