VALIDATION OF DAILY INCREMENTS IN THE OTOLITH MICROSTRUCTURE OF NORWEGIAN SPRING-SPAWNING HERRING (CLUPEA-HARENGUS L)

Norwegian spring-spawning herring larvae were raised in an outdoor mesocosm for 65 days from hatching. The otolith microstructure in the sagittae of larvae sampled during the experiment was examined and daily pattern in increment formation was validated. Formation of the first increment (hatch check) corresponded to the end of the yolk-sac stage. The estimated hatching dates of 43.9% of the larvae were within the range of the observed hatching date, a period of 3 days. Age and hatching date estimates were less precise in larvae younger than 25 days, compared to those older. Starvation of the larvae resulted in an uncoupling of the body size:otolith size ratio. © 1992 International Council for the Exploration of the Sea.