Temperature dependent
otolith growth of larval and early juvenile Atlantic cod (Gadus morhua
)
E.
Otterlei, A. Folkvord, G. Nyhammer-2002
ICES
Journal of Marine Science, 59(2): 401-410
Abstract:
The otolith (lapillus) size-fish size
relationship was examined for offspring of two Atlantic cod
stocks, reared at different temperatures. Larvae and early
juveniles reared at high temperatures (fast growing),
had larger otoliths at a given length than fish reared
at low temperatures (slow growing). Within a given temperature group, however, faster growing cod tended
to have proportionally smaller otoliths, although the difference was not always significant. Moreover, the
otolith radius of Norwegian coastal cod was larger, at given fish lengths, compared to that of the northeast
Arctic cod. An ontogenetic shift in the allometric
otolith size-fish size relationship occurred at onset
of metamorphosis (12mm).Mean daily otolith growth of
the lapillus radius increased with increasing temperature from 4 to 14°C and was size dependent and peaked at a
larval length of about 25mm. The radius of the
lapillus at hatching was poorly correlated with larval length at day 56 for both stocks, suggesting that the
potential for fast growth may not necessarily be
reflected in traits present at hatching. The effects of temperature, stock and ontogeny are discussed with
regard to the assumption of constant proportionality
between otolith growth and fish growth.
(University of Bergen, Department of Fisheries and
Marine Biology, PO Box 7800, N-5020, Bergen, Norway, Tel: +47 55 58 44 56;
fax: +47 55 58 44 50; e-mail of A. Folkvord: arild.folkvord@ifm.uib.no)