Temperature-induced
ontogenetic plasticity in sea bass (Dicentrarchus labrax)
G. Koumoundouros, P. Divanach, L. Anezaki, M. Kentouri-2001
Marine Biology, 139(5): 817-830
Abstract:
We
studied the ontogeny of Dicentrarchus labrax comparatively
under constant rearing temperatures of 13, 15 and 20°C. At hatching,
yolk-sac larval morphometry differed significantly between the temperatures
and especially between the two extremes, while at the end of the yolk-sac
larval stage, it mainly differed between the two lower temperature regimes
and that of 20°C. Compared with the two lower temperature conditions, at 20°C
D. labrax presented a significant ontogenetic acceleration
which was morphologically expressed either as a significantly smaller total
length (TL) at feeding onset, notochord flexion and fin differentiation, or
as shifts of the allometric inflection points of 8 out of the 15
morphometric characters studied. Additionally, temperature significantly
affected the allometry coefficients, with a decreasing growth intensity as
the temperature difference decreased. The rate of TL growth increased under
elevated temperature conditions throughout the entire ontogenetic period,
except during the early larval period (feeding onset to metamorphosis
onset), at which time D. labrax presented equal growth rates
at 15°C and 20°C. The results are discussed with respect to the ontogeny
of the functional morphology and the meanings of temperature-induced
ontogenetic plasticity for the survival of fish larvae.
(Biology Department, University of Crete, P.O. Box 1470, 71110 Irákleion, Crete, Greece, Tel: +30-81-242022, Fax: +30-81-241882, E-mail: koumound@imbc.gr)