Maternal, paternal and temperature effects on otolith size of young herring (Clupea harengus L.) larvae

Investigations were carried out to clarify the timing of first check formation, and the influence of maternal, paternal and temperature effects on otolith size of young herring larvae. Three male and three female herring of the Norwegian spring-spawning-herring-stock were used as parental fish in a 3 X 3 factorial design, resulting in nine parental combinations. Eggs from each of the combinations were incubated at 4, 8 and 12 degrees C. Larvae were sampled at two ontogenetic stages: newly hatched and at the end of the yolk sac (EYS) stage. In addition, some larvae were also reared with wild zooplankton and sampled 16-21 days after hatching to compare first check size with observed otolith size of unfed larvae. The first check was deposited 1-2 days after hatching and before onset of exogenous feeding at 12 degrees C. Significant maternal and temperature effects were observed on the size of sagitta and lapillus at hatching, with smaller otoliths at higher temperatures. Larval length showed a similar temperature response as the otoliths, whereas larval dry mass showed an opposite trend. Otolith size and larval length and mass were poorly correlated, and large variability in the otolith data were evident. Temperature also influenced the measured variables at the EYS stage while the maternal influence was not as strong as at hatching. No sagittal growth between hatching and the EYS stage was observed at 4 degrees C although larval standard length increased. Large variability Limits the direct application of the first check size as a reliable tool for discrimination of units within and between fish stocks. (C) 1999 Elsevier Science B.V. All rights reserved.