The experiment was carried out at the Institute of Marine Biology,
Biotechnology and Aquaculture (previously the Institute of Aquaculture)
of the Hellenic Center for Marine Research, Crete, Greece. European sea
bass eggs were obtained after natural spawning (January) of a
captivity-held wild broodstock that was kept under natural photothermal
regime. For larval rearing, eggs obtained from a single day's
spawning (multiple females and males) were transferred to indoor
500-l cylindro-conical tanks. The eggs were incubated (in duplicates)
at two temperatures (15 and 20 °C) during the period until metamorphosis
(~17 mm in total length, TL), which occurred after 66 and
55 days post spawning (dps) at 15 and 20 °C, respectively. For the
20 °C groups, the eggs were acclimatized over the course of 24 h from
their spawning temperature of 16 °C. The mean (±SD) water temperatures
in the two groups during the experimental period were 15.2 ± 0.4
and 19.9 ± 1 (Fig. 1). Fish were offered progressively enriched rotifers,
freshly hatched Artemia spp., 24-h enriched Artemia and artificial feed
(as reported in Sfakianakis et al., 2006a), according to standard larval
rearing protocols (Moretti et al., 2005). At frequent intervals (every
1–2 days) during the experimental period samples of fish (n = 10)
were taken in order to monitor development and growth, and adjust
feeding regimes. To maintain control over the water temperature, the
experimental tanks were connected to recirculation units (one per
temperature regime) equipped with a biofilter and chiller systems.
Water renewal was gradually increased during the study to ensure
optimal water quality, while gaseous oxygen was supplemented when
needed during the nursery period, in order to maintain a level of
saturation N70% in the rearing water. When the experimental period
ended at 55 dps (20 °C treatment) and 66 dps (15 °C treatment), fish
were then reared at a common temperature, which started at 17.4 °C
and fluctuated until harvest time between 14.5 °C in February and
26.5 °C in August (Fig. 1).