LARVAL GROWTH RATES OF THE PACIFIC SARDINE SARDINOPS SAGAX OFF CENTRAL CHILE, DETERMINED BY DAILY RING COUNTS IN OTOLITHS

Abstract

Growth rates of Sardmops sagax (Jenyns, 1842) were determined using counts of daily increments on sagitta otoliths infield collected larvae from the Talcahuano zone (36°35'S; 73°03'W). Size ranged from 5 to 22 mm length that corresponded to an age interval from 3 to 41 days after yolk absorption. Otolith’s radius and diameter show an allometric relationship with respect to larval size, and consequently with age. A simple power regression fitted best the data on age and larval size. Growth rates are lower than those reponed elsewhere for this species, probably in response to low environmental temperature (12.5°C). Typically S. sagax grows 0.4 mm/day when 13.0 mm in size, a rateequivalent to 50% of the rate at 18,6°C. Ecological implications of this finding are discussed.