Cruise report of acoustic assessment of the Iceland-East Greenland-Jan Mayen capelin stock in the autumn 2024

Ágrip

Í þessari skýrslu eru kynntar helstu niðurstöður leiðangurs frá haustinu 2024 sem hefur það meginmarkmið að meta stærð loðnustofnins við Ísland, Austur-Grænland og Jan Mayen. Leiðangurinn fór fram 21. ágúst til 1. október á RS Árna Friðrikssyni og Polar Ammassak fyrir hönd Hafrannsóknastofnunar og RS Tarajoq fyrir hönd Grænlands. Stofnstærðarmælingar á loðnu byggðu á bergmálsmælingum og sýnum frá flotvörputogum. Auk þess var ástand vistkerfisins rannsakað með sýnatökum á svifdýrumi með WP2 og bongo netum og umhverfis mælingum með sondu (CTD). Kynþroska loðnu var aðallega að utan finna íslenska landgrunnsins norðvestur af landinu. Í vestur hluta Grænlandssunds var kynþroska loðna í bland við ókynþroska, en útbreiðsla kynþroska loðnur náði ekki langt austur fyrir Grænlandssundið. Ekkert varð var við loðnu vestan við Jan Mayen hrygginn eða Kolbeinseyjarhrygginn. Ókynþroska loðna fannst meðfram á landgrunni Grænlands með mesta þéttleika á suðvestur hluta svæðisins og í Grænlandssundi. Heildarfjöldi loðnu nam 74 milljörðum þar sem ókynþroska hlutinn var 58,5 milljarðar. Heildarlífmassi loðnu var 610 þúsund tonn og þar af var kynþroska 307 þúsund tonn.

Abstract

The report presents the main results of a survey aimed for assessing the stock size of Iceland-East Greenland-Jan Mayen capelin stock in the autumn 2024. The survey was conducted during 21 August to 1 October by the r/v Arni Fridriksson and f/v Polar Ammassak on behalf of Marine and Freshwater Research Institute in Iceland and r/v Tarajoq on behalf of Greenland Institute of Natural Resources. Abundance estimations were based on acoustic measurements and biological sampling with pelagic trawls. Moreover, the ecosystem conditions were studied with sampling of zooplankton by WP2 and bongo nets and environmental measurements with CTDs. Maturing capelin was mainly observed outside the Icelandic continental shelf off NW Iceland. In western part of Denmark Strait maturing capelin was mixed with immature capelin, but the distribution of maturing capelin reached not far east of Denmark Strait. Further, no capelin was found west of the Jan Mayen ridge or Kolbeinsey ridge. Immature capelin was found along the Greenlandic shelf, dominating in southwestern part of the survey area and Denmark Strait. The total number of capelin amounted to 74 billion where immature juveniles were 58.5 billion. The total biomass estimate was 610 000 tonnes of which about 307 000 tonnes were mature capelin.