Distinguishing between spring and autumn spawned herring from daily increments, a preliminary report
Original version
This report is not to be cited without prior reference to the authorsAbstract
Otoliths from Norwegian Spring Spawning herring larvae, collected on a
cruise in May 1985 and North Sea Autumn Spawned herring larvae,
collected on a cruise in Desember 1987, were examined for daily
increments. A greater distance from the otolith nucleus to the first
observed increment was seen in Norwegian Spring Spawning herring
larvae (14.0 ± 3.4 µm) than in North Sea Autumn Spawned herring larvae
(5.0 ± 1.6 µm). In addition the results indicate that species from autumn
and spring spawning stocks can be separated by a comparition of the
increment widths in the otoliths. In a distance between 40 and 60 µm
from the nucleus, the increments in the North Sea Autumn Spawned
herring larvae had a width less than 1.5 µm, while the corresponding
widths in spring spawners were greater than 2.0 µm.