Somatic and molt production in Euphausia mucronata off central-southern Chile: the influence of coastal upwelling variability

摘要: Seasonal and inter-annual variability in population abundance, biomass, somatic molt production of the Humboldt Current krill Euphausia mucronata were studied during a monthly time series (August 2002 to June 2007) at Stn 18 (36° 30' S, 73° 07' W) off central-southern Chile. Experimental measurements performed (in 2007 2008) north- ern Chile (2010) order estimate vital rates for use E. secondary calculation 18. Coastal upwelling intensity was main oceanographic process found control abundance biomass on seasonal scales. Spawning peaks structure indicate that produces least 2 generations per year. The spawning period occurs austral spring when phytoplankton concentration is high. A second, less intense end summer early autumn. had mean 100 mg C m �3 an integrated annual 2432 yr �1 , with overall production/ ratio (P/B) 24. In May 2007, maximum daily 5 g total 63 d observed. These estimates are consider- ably higher than those reported other species coastal regions. Multivariate analyses upwelling-favorable winds promote high sec- ondary production, but transition periods from downwelling conditions. Results suggest has highly effi- cient behavioral strategy attain recover rapidly potential off- shore losses due advective processes productive ecosystem.