| LarvalBase | FishBase |
| Main Ref: | McVey, J.P., 1991 | |||||||
| Territory: | ||||||||
| locality: | ||||||||
| Nursery System : | indoor tanks (flow through) | |||||||
| Details: | Usually, tanks (fiberglass, PVC, concrete, various shape) with a volume of several hundred up to 2000 liter and a depth of about 1m can be successfull used for larval rearing. A water exchange of 5-30%/h (increasing from day 1 to day 20) is recommended in the rearing tanks. If "green water" technique is applied, algae (e.g. Nannochloris, Chlorella) are added everyday to the water, maintaining a density of about 500,000cells/ml. | |||||||
| Ref.: | ||||||||
| Number of larvae: | ||||||||
| Stocking density: | 30 number/l | |||||||
| Culture system: | other | |||||||
| Water Supply | ||||||||
| Main Water Source: | ocean | |||||||
| Supplemental Water Source: | brackish water | |||||||
| Temp (°C) | Salinity (psu) | pH | Oxygen (mg/I) | Illumination (Lux) | |
| Min | 16 | 15 | 7 | 6 | 1000 |
| Max | 22 | 35 | 8 | 10 | 2000 |
| Production | ||||||||
| Time to fry | Mortality | First feed | ||||||
| (days) | (d-degree) | (%) | (d-degree) | (days) | ||||
| min | 30 | 10 | 2 | |||||
| max | 40 | 60 | 3 | |||||
| Production /cycle | ||||||||
| Production /year | ||||||||
| FCR | ||||||||
| Growth rate | Hatching 0.1-0.2mg, 1 months 50-75mg, 3 months 1.5-2.5g | |||||||
| Nutrient inputs | ||||||||
| Main food | Rotifers (Brachionus spec.), Artemia nauplii, artificial micro diets | |||||||
| Description of nutrient input | First feeding occurs 2-3 days posthatching, Brachionus spec. (size 90 - 240µm long, large size strain) are appropriate as first food und offered for about 10 day with a density of 10-20/ml. Newly hatched Artemia nauplii are introduced at day 8 with a density of 1-2/ml, and gradually replace rotifers. Both food organisms will be enriched before offering to the larvae (algae for Rotifers and specific enrichment substances for Artemia nauplii). Enriched Artemia metanauplii will be offered until conversion to artificial diets (weaning between 28 and 30 days). 90% of the prey offered has to be ingested within 24h. | |||||||
| Comments | At hatching, turbot larvae are 2.1 - 2.8 mm in length, have one oil globule and they are planctonic. Relatively high mortality during larval stages is a main problem of turbot culture. A first mortality peak appears sometimes in the beginning due to transfer stress of larvae into rearing tanks. The most typical mortality occurs between day 6 and 8, probably for "natural" reasons of unsufficient developed digestion mechanisms. Another peak in mortality sometimes occur between days 10 and 15. Furthermore, larval turbot are sensitive to an excess level of dissolved gas which causes swim bladder hypertrophy. The rearing environment should be kept as stable as possible. Between days 2-3, the mouth opens and exogenous feeding begins while yolk sac and oil glube are quickly mobilized and will disappear at days 5 and 7, resp. (vitellogenic period). In turbot larvae, metamorphosis take place over a long period. "Flattening" takes place progressively from day 15, the migration of the eye takes place from day 30, but larvae are still pelagic. Becoming benthic not happened before day 40 post hatch. | |||||||
| Rearing essay | ||||||||
| Comments and Corrections Sign our Guest Book |