Growth in the 0-group of Argentine hake (Merluccius hubbsi) from the Argentine-Uruguayan Common Fishing Zone

Abstract

Growth of hake (Merluccius hubbsi) in the 0-group from the Argentine-Uruguayan Common Fishing Zone was studied and spawning data were back-calculated by identifying daily growth rings in otoliths of specimens caught during research cruises performed in May 1997, May 1998 and June 1999. Total length (TL) range was 14-69 mm. Increments were read under microscope using an otolith daily ring measurement system (RATOC). Changes in the increment width data present a pattern that seemed to be similar, and independent from birth date of individuals. Data observed and back-calculated showed good accordance with the Laird-Gompertz model. Significant differences between coefficients were found in all comparisons of growth curves for observed and retrocalculated data. Growth rates estimated from observed data showed maximum values (ca. 0.54 mm d-1) at the stage of late larvae and minimum values at the stage of large early juveniles (ca. 0.25 mm d-1). For each year back-calculated hatching dates corresponded to the scarce mid-summer reproductive activity.