Growth of Northwest Iberian juvenile hake estimated by combining sagittal and transversal otolith microstructure analyses

摘要

Daily growth of Atlantic juvenile hake from Northwest Iberia has been estimated employing a new approach combining analyses of transversal and sagittal sections of the otoliths along the ventral radius. Age of juvenile hake ranging from 3 to 25cm collected during a spring 2002 survey was estimated. Somatic growth followed a power fit: Fish size (TL)=3.3254*age super(0) super(.) super(7) super(3) super(3) super(6) (r super(2)=0.87, p<0.001, n=76), yielding an average individual growth rate of 0.66mm/day (+/-0.06). The growth model indicates that after a year's life a juvenile can reach 25cm. Otolith ventral radius ranged from 401 to 1842 mu m and daily increments were between 104 and 387. Fish growth and otolith growth were closely related (r super(2)=0.92 p<0.001, n=76). These first results of daily growth rates for the Southern stock corroborate the fast-growth hypothesis of this species. The evolution of increment widths from hatch dates onwards reveals important seasonal growth peaks during July-August and October-November. A comparison with prior data and discussion is also presented in the light of recent work on hake juveniles and tagging-recapture experiences.