Krill length frequency distribution through subarea 48.3 in 1988 January-February is considered in the frame of hypothesis of krill resources forming from two sources: Antarctic Circumpolar Current and Weddell Scotia Sea water flow. It is shown, that small krill with the mode of about 33 mm is distributed in the coastal zone of about 7-40 miles wide, further is situated the boundary zone at the distance of about 30-60 miles, beyond boundary zone occurs larger krill with the mode of about 49 mm. Krill length frequency distribution is unimodal in the coastal and off-shore zones and bimodal in boundary zone. Krill distribution well corresponds to the water flows mentioned. Further analyses revealed heterogeneity in Weddell Sea krill distribution, there are spots of krill of increased length, where krill is retained for certain time and have a possibility to grow longer. Difference in krill length in such spots and main water flow may reach 6 mm. Such spots may be considered as initial stage of krill aggregations forming inside quasi-stationary vortices, further development of this scenario leads to the creation of commercially important krill aggregations.
Krill length frequency distribution in Subarea 48.3 in
January–April 1988 in relation to sources of its origin
Numéro du document:
WG-EMM-03/40
Point(s) de l'ordre du jour
Résumé