Decadal tracking of Atlantic Bluefin Tuna

Sampling event
Latest version published by Ocean Tracking Network on Aug 27, 2025 Ocean Tracking Network
Publication date:
27 August 2025
Published by:
Ocean Tracking Network
License:
CC-BY 4.0

Download the latest version of this resource data as a Darwin Core Archive (DwC-A) or the resource metadata as EML or RTF:

Data as a DwC-A file download 3 records in English (8 KB) - Update frequency: unknown
Metadata as an EML file download in English (15 KB)
Metadata as an RTF file download in English (13 KB)

Description

This is the OBIS extraction of the Ocean Tracking Network and Technical University of Denmark (DTU) Decadal tracking of Atlantic Bluefin Tuna, consisting of the release tagging metadata, i.e. the location and date when the tagged animal was released, and summarized detection events of tagged individuals. If readers are interested in the source dataset they may also inquire with the project PIs as listed here or on the OTN web site (https://members.oceantrack.org/project?ccode=BFTDK).

Abstract:In 1930-1950, bluefin tuna were commercially fished in Denmark and Sweden. Landings were several hundred tonnes per year, with a peak of 2000t in Sweden in 1942. Fishing continued in the next two decades and then it gradually disappeared. Sport fishing for bluefin tuna in the Kattegat and the Sound continued until the 1960s. But then, bluefin tuna catches became increasingly rare. After decades of absence, bluefin tuna have recently been sighted again in the Northeastern Atlantic, inter alia off the coast of Bohuslän and in the Skagerrak and Kattegat. In 2016 and 2017, large schools of several hundred large individuals were observed. These adult fish hunted mackerel and herring during late summer and autumn. The reasons for the return and origin of the bluefin tuna in the North Sea-Skagerrak-Kattegat are unknown. This project will use electronic tags to help understand its migration patterns and behavior, avoid unwanted bycatch and support sustainable management of the stock. Attaching long life acoustic tags holds the potential to observe transatlantic migration as well as repeatability of the migratory pattern, by using the OTN network of receivers.

Data Records

The data in this sampling event resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 3 records.

2 extension data tables also exist. An extension record supplies extra information about a core record. The number of records in each extension data table is illustrated below.

Event (core)
3
ExtendedMeasurementOrFact 
18
Occurrence 
11

This IPT archives the data and thus serves as the data repository. The data and resource metadata are available for download in the downloads section. The versions table lists other versions of the resource that have been made publicly available and allows tracking changes made to the resource over time.

Versions

The table below shows only published versions of the resource that are publicly accessible.

How to cite

Researchers should cite this work as follows:

Aarestrup, K. 2018. Decadal tracking of Atlantic Bluefin Tuna. Accessed via the Ocean Tracking Network OBIS IPT on INSERT DATE

Rights

Researchers should respect the following rights statement:

The publisher and rights holder of this work is Ocean Tracking Network. This work is licensed under a Creative Commons Attribution (CC-BY 4.0) License.

GBIF Registration

This resource has not been registered with GBIF

Keywords

ACOUSTIC TAGS; EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > FISH; Occurrence; Samplingevent

External data

The resource data is also available in other formats

Decadal tracking of Atlantic Bluefin Tuna https://members.oceantrack.org/project?ccode=BFTDK ASCII HTM

Contacts

Ocean Tracking Network Data Centre
  • Originator
  • Point Of Contact
  • Data Manager
Ocean Tracking Network
  • Dalhousie University
B3H 4J1 Halifax
Nova Scotia
CA
  • +1 (902) 494-4101
Jonathan Pye
  • Metadata Provider
  • Data Manager
Ocean Tracking Network
CANADA
Kim Aarestrup
  • Content Provider
  • Principal Investigator
Technical University of Denmark
DENMARK
Anders Koed
  • Content Provider
Technical University of Denmark
DENMARK
Martin Lykke Kristensen
  • Content Provider
Technical University of Denmark
DENMARK

Geographic Coverage

REGION HOVEDSTADEN

Bounding Coordinates South West [57.96, 10.75], North East [58.28, 11.09]

Temporal Coverage

Start Date 2018-08-24

Project Data

In 1930-1950, bluefin tuna were commercially fished in Denmark and Sweden. Landings were several hundred tonnes per year, with a peak of 2000t in Sweden in 1942. Fishing continued in the next two decades and then it gradually disappeared. Sport fishing for bluefin tuna in the Kattegat and the Sound continued until the 1960s. But then, bluefin tuna catches became increasingly rare. After decades of absence, bluefin tuna have recently been sighted again in the Northeastern Atlantic, inter alia off the coast of Bohuslän and in the Skagerrak and Kattegat. In 2016 and 2017, large schools of several hundred large individuals were observed. These adult fish hunted mackerel and herring during late summer and autumn. The reasons for the return and origin of the bluefin tuna in the North Sea-Skagerrak-Kattegat are unknown. This project will use electronic tags to help understand its migration patterns and behavior, avoid unwanted bycatch and support sustainable management of the stock. Attaching long life acoustic tags holds the potential to observe transatlantic migration as well as repeatability of the migratory pattern, by using the OTN network of receivers.

Title Decadal tracking of Atlantic Bluefin Tuna
Funding OTN is a research and technology development initiative headquartered at Dalhousie University, in Halifax Nova Scotia. OTN is funded by the Canada Foundation for Innovation (CFI) and is grateful to have once received funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Social Sciences and Engineering Research Council of Canada (SSHRC). OTN is also grateful for the continued support from Research Nova Scotia, and OTN's host institution, Dalhousie University.
Study Area Description No study area description for this project was provided to OTN for publication.
Design Description A wide range of aquatic species are tagged with small electronic transmitters, surgically implanted or attached externally, which can operate for up to 20 years. Acoustic receivers arranged in line on the ocean floor as well as attached to buoys, gliders and large animals (e.g. grey seals) pick up the coded acoustic signals from these tags identifying each tagged sea creature that passes within half a kilometer of the receiver. Data collected by these listening stations are subsequently uploaded to one of many compatible data nodes, adding to the reach of an intercompatible network of networks designed and maintained by the Ocean Tracking Network, producing current and reliable records for every part of the globe. Certain classes of electronic tags and listening equipment (receivers) may also be outfitted or co-located with sensors to measure the ocean's temperature, depth, salinity, currents, chemistry, and other properties.

The personnel involved in the project:

Kim Aarestrup

Sampling Methods

Acoustic tags released.

Study Extent Program started 2018-08-24 and ran until
Quality Control OTN species names are verified using the World Register of Marine Species (WoRMS). If species names on new data cannot be verified against (a) known valid names in OTN, and/or (b) WoRMs the Data Provider will be notified so they can check they are correct. Names that cannot be placed after checking with WoRMS are, where possible, placed on the basis of other authoritative sources, such as the Fishbase or ITIS; and once completely verified a request will be sent to WoRMS for addition of the verified species name. http://members.oceantrack.org/data/discovery/byspecies

Method step description:

  1. This resource was created by the Ocean Tracking Network Data Centre as a summarized representation of animal presence determined by electronic tagging efforts. Darwin Core (DwC) records were extracted from the OTN database and filtered and summarized according to international agreed-upon standards.

Bibliographic Citations

  1. Aarestrup, K. 2018. Decadal tracking of Atlantic Bluefin Tuna In: Ocean Tracking Network Data Centre, Halifax Canada / otndc@dal.ca Retrieved: 2030-08-27 from db.load.oceantrack.org

Additional Metadata

Access Constraints: none Use Constraints: Acknowledge the use of specific records from contributing databases in the form appearing in the 'Citation' field thereof (if any); and acknowledge the use of the OBIS facility. For information purposes, email to info@obis.org the full citation of any publication made (printed or electronic) that cites OBIS or any constituent part. Recognize the limitations of data in OBIS. See https://manual.obis.org/policy.html#disclaimer for more details

Purpose

These data are for display on the OBIS portal and associated mapping programs and for download to personal computers for ad-hoc end-user analysis.

Alternative Identifiers https://members.oceantrack.org/ipt/resource?r=otndtudecadaltrackingofat