Cristin-resultat-ID: 1941508
Sist endret: 30. september 2021, 14:47
Resultat
Vitenskapelig foredrag
2021

Direct measurements of the migration speed of spawning herring

Bidragsytere:
  • Egil Ona
  • Guosong Zhang
  • Nils Olav Handegard
  • Sverre Berg og
  • Lars N Andersen

Presentasjon

Navn på arrangementet: ICES WGFAST and ICES-FAO WGFTFB
Sted: Bergen
Dato fra: 19. april 2021
Dato til: 23. april 2121

Arrangør:

Arrangørnavn: ICES

Om resultatet

Vitenskapelig foredrag
Publiseringsår: 2021

Beskrivelse Beskrivelse

Tittel

Direct measurements of the migration speed of spawning herring

Sammendrag

The Norwegian Spring Spawning herring stock migrates in January-February each year from the feeding area in the Norwegian Sea to the spawning grounds on the Norwegian coast. The bio-mass and age composition of the spawning stock is measured with three rented purse seiners in a standard zig-zag survey design. Depending on the progress speed of the survey and its survey design, fish migration may significantly affect in the final spawning stock estimates. Since most of the fish in this survey migrate in dense layers in midwater or close to the bottom, only a small fraction of the moving biomass can be isolated for sonar school tracking algorithms. In February 2020, a new Kongsberg ES150C, a combined broad band echo sounder and ADCP system was mounted on one of the vessels and logged the raw and processed current data from the system. During the survey, selected data sets with strong herring backscattering were isolated and used to directly measure the migration speed and direction of the herring as well as for the surround-ing water masses. For computing a representative mean migration speed for each of 13 strata, we weighed the migration speed with the acoustic density, and evaluated the potential migration error in the spawning stock estimate. Measurement methods, limitations and processing are described.

Bidragsytere

Egil Ona

  • Tilknyttet:
    Forfatter
    ved Økosystemakustikk ved Havforskningsinstituttet

Guosong Zhang

  • Tilknyttet:
    Forfatter
    ved Økosystemakustikk ved Havforskningsinstituttet
Aktiv cristin-person

Nils Olav Handegard

  • Tilknyttet:
    Forfatter
    ved Økosystemakustikk ved Havforskningsinstituttet

Sverre Berg

  • Tilknyttet:
    Forfatter
    ved Kongsberg Gruppen

Lars N Andersen

  • Tilknyttet:
    Forfatter
    ved Kongsberg Gruppen
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