Table 2 Range of the main rearing parameters during the larval-rearing period.
From: Variability of key-performance-indicators in commercial gilthead seabream hatcheries
Parameter | mean ± SD | min | max | n |
|---|---|---|---|---|
Larval rearing | ||||
Tank volume (m3) | 11.8 ± 4.1 | 10 | 25 | 74 |
Tank depth (m) | 1.3 ± 0.4 | 0.5 | 2.2 | 55 |
Tank shape | Cylindrical (74/74) | |||
Tank coloura | B (53/74), G (18/74), Y(3/74) | |||
Number of tanks in the same room | 14 ± 8 | 5 | 36 | 73 |
Tank disinfection prior stocking | Yes (74/74) | |||
Duration of dry period prior stocking (d) | 6.6 ± 7.5 | 1 | 31 | 68 |
Water source | Borehole (55/74), open-sea (19/74) | |||
UV water-treatment | Yes (89%, 66/74) | |||
Water Ozonation | No (85%, 63/74) | |||
Use or RAS for the larval rearing | NO (74/74) | |||
Use or RAS for the weaning | Yes (77%, 57/74) | |||
Initial stocking density (fish/L) | 152 ± 61 | 70 | 330 | 74 |
Use of eggs of different ages | No (95%, 70/74) | |||
Onset of siphon cleaning (dph) | 9.3 ± 3.5 | 0 | 13 | 74 |
Age at fish removal from the larval-rearing tank (dph) | 44 ± 13 | 26 | 70 | 73 |
Total rotifers (106) | 6968 ± 3746 | 2366 | 21,336 | 74 |
Total Artemia instar I nauplii (106) | 4572 ± 1664 | 1625 | 9909 | 72 |
Total Artemia instar II nauplii (106 ) | 283 ± 211 | 0 | 752 | 74 |
Rotifer adjustment levels (ind/mL) | 4–12 | |||
Artemia instar I adj. levels (ind/mL) | 0–3 | |||
Artemia instar II adj. levels (ind/mL) | 0.25–5 | |||
Daily number of algae inputs | 1 to continuous | |||
Daily number of rotifers provisions | 2 to continuous | |||
Daily number of Artemia provisions | 5 to continuous | |||
Algae usedb | Iso, Nan, Chl, Nps, other | |||
Use of more than one algal species | No (78%, 58/74 | |||
Number of enrichment prod. used (rotifers) | One (39/74) to two (35/74) | |||
Number of enrichment prod. used (Artemia) | 1 (74/74) | |||
