Krill demography and large-scale distribution in the Western Indian Ocean sector of the Southern Ocean (CCAMLR Division 58.4.2) in Austral summer of 2006

摘要: Krill demography was studied during a large-scale survey of the South Western Indian sector Southern Ocean conducted in late January to February 2006 (BROKE-West). The progressed from 30oE 80oE and bounded North by 62°S. average krill density calculated catches RMT 8 net for four geographical strata ranged 0.84-68 individuals per 1000 m-3, with overall mean 6.7 m-3. distribution its population structure were analysed using cluster mixture analysis length frequency distribution, showing small sized (modal size 25-30 mm) broadly distributed centre western area whereas middle large 35-45 mm 45-55 mm, respectively) mainly eastern half area. These findings are discussed context observed geographic oceanographic structures; continental slope area, fronts, currents gyres. Proportional recruitment indices 0.089-0.226 R1 (age 1+ recruitment) 0.204-0.440 R2 2+ strata. Recruitment revealed differences between halves surveyed suggesting possible existence separate self-sustaining populations linked Weddell Gyre Prydz Bay systems. larvae along shelf break, implying early onset spawning mid-November. series coastal polynyas developing spring may be one important habitats allowing use season phytoplankton growth maturation spawning, those would transported westwards current slope.