What are they? And how many are they?

Project

Hydroacoustic monitoring of fish stocks to determine stock parameters and distribution patterns

Hydroacoustic methods utilize sound waves to detect marine organisms. Modern echosounders can not only be used to determine stock parameters but also allow identification of habitat use, species composition and further parameters of marine ecosystems. These data are the basis for predictive models allowing estimating sustainable catch quotas.

Background and Objective

Hydroacoustic monitoring methods allow direct determination of stock parameters and distribution patterns of (mainly) pelagic fish species. To utilize these parameters as a basis for predictive models estimating sustainable catch quantitites and to allow conclusions on distribution patterns and habitat use of different fish species, spatially highly resolving surveys of corresponding areas are required. Further, by concurrently measuring environmental parameters, estimates on distribution patterns and habitat preferences or habitat usage of different fish species can be made.

Target Group

Policy-makers in marine environmental as well as common fisheries policy; Fisheries scientists; interested community

Approach

Within the framework of international surveys that are coordinated by the International Council for the Exploration of the Sea (ICES) we participate in surveys monitoring abundance indices of important fish stocks in the North Sea, Baltic Sea and Northeast Atlantic. On predefined hydroacoustic transects in the survey area data on echo distribution and total echo strength are collected, together with environmental parameters (temperature, salinity etc.). Based on total echo strenght/distribution, on species composition and corresponding length frequency distributions from targeted pelagic trawl hauls and based on backscattering characteristics of different fish species we are able to provide spatially highly resolved data on abundance, biomass and age structure of e.g. herring, sprat, blue whiting and redfish. These data are further used in internationally coordinated assessments of status and sustainable use of the corresponding stocks.

Hydroakustiksurvey auf See — Während der Hydroakustiksurveys müssen im Akustiklabor an Bord die Echolote permanent überwacht werden, um eine ununterbrochene Datenaufzeichnung zu garantieren und um den weiteren Surveyverlauf, z.B. Vergleichsfänge, koordinieren zu können. (© Thünen-Institut/Matthias Schaber)

Heringsschwärme im Öresund — Dichte Schwärme von Heringen (Clupea harengus) erscheinen auf dem Echolot. Die Rohdaten werden aufgezeichnet und mittels spezieller Software nachbearbeitet und ausgewertet. Dies dient z.B. der Erfassung von Bestandsparametern wie Abundanz und Biomasse. (© Thünen-Institut/Matthias Schaber)

Einholen des Netzes — Auch im Rahmen von Hydroakustiksurveys müssen Vergleichsfänge mit Schleppnetzen durchgeführt werden, um Artenzuammensetzung sowie biologische Parameter von Zielfischen im Untersuchungsgebiet zu erhalten. (© Thünen-Institut/Matthias Schaber)

Fangsortierung — Für eine genaue Zuordnung der aufgezeichneten Echogramme sowie für die Erfassung z.B. der Alters- und Längenstruktur verschiedener Fischarten im Untersuchungsgebiet müssen Vergleichsfänge mit Schleppnetzen durchgeführt werden. Diese werden an Bord nach Fischarten getrennt sortiert und weiter aufbereitet. (© Thünen-Institut/Matthias Schaber)

Data and Methods

Hydroacoustic data are collected with modern scientific multifrequency echosounders.

Our Research Questions

How can hydroacoustic data be used to estimate abundances and distribution patterns of different marine species? What is the status of different (pelagic) fish stocks?

Preliminary Results

Estimates of biomass, abundance, age structure and distribution of pelagic fish stocks in the North Sea, Baltic Sea and North Atlantic

Duration

1.2001 - 12.2020

More Information

Projekt type:
Project status: ongoing

Publikationen

Gröhsler T, Schaber M (2014) Annex 6: Cruise reports from other acoustic surveys in the area : Annex 6a: Western Baltic acoustic survey ; Survey report for FRV "Solea" ; German Acoustic Autumn Survey (GERAS), 30 September 2013 - 19 October 2013. In: Report of the Working Group of International Pelagic Surveys (WGIPS) ; 20-24 January 2014. Copenhagen: ICES, pp 224-251
Gröhsler T, Schaber M (2014) Survey Report for FRV "Solea" German Acoustic Autumn Survey (GERAS) 30 September 2013 - 19 October 2013. In: Report of the Baltic International Fish Survey Working Group (WGBIFS) : 24-28 March 2014 ; Gdynia, Poland. Copenhagen: ICES, pp 250-258
Planque B, Kristinsson K, Astakhov A, Bernreuther M, Bethke E, Drevetnyak K, Nedreaas K, Reinert J, Rolskiy A, Sigurdsson T, Stransky C (2013) Monitoring beaked redfish (Sebastes mentella) in the North Atlantic, current challenges and future prospects. Aquatic Liv Res 26(4):293-306, doi:10.1051/alr/2013062
Schaber M, Gröhsler T (2013) Survey Report for FRV "Solea" 2-21 October 2012. In: Report of the Baltic International Fish Survey Working Group (WGBIFS) : Annex 8: Cruise reports of acoustic surveys BASS and BIAS in 2012. Copenhagen: ICES, pp 266-289
Bethke E, Götze E, Planque B (2010) Estimation of the catchability of redfish and blue whiting for survey trawls in the Norwegian Sea. J Appl Ichthyol Suppl 26.1:47-53
Schaber M, Hinrichsen HH, Neuenfeldt S, Voss R (2009) Hydroacoustic tracking of individuals in environmental gradients - Baltic cod (Gadus morhua L.) vertical distribution during spawning. Mar Ecol Progr Ser 377:239-253, doi:10.3354/meps07822
Schaber M, Hinrichsen HH, Neuenfeldt S, Voss R (2007) Hydroacoustic resolution of small-scale vertical distribution of cod (Gadus morhua L.) in the central Baltic Sea at different hydrographic regimes : ICES CM 2007/ G:20. Copenhagen: ICES
Schaber M, Stepputtis D, Hinrichsen HH, Kraus G, Andersen KH (2005) Distribution of adult cod (Gadus morhua L.) in the Central Baltic Sea in relation to hydrographic conditions based on hydro-acoustic single-fish detection : ICES CM 2005/ AA:02 . Copenhagen: ICES

Director

Deputy

Secretariat