Attempts at larval rearing of the endangered western European sturgeon, Acipenser sturio (Acipenseridae), in France
Preliminary results are reported of larval rearing of the critically endangered European Atlantic sturgeon, Acipenser sturio L. Two live food items (chironomids and Artemia salina nauplii) and two compound diets were compared as first feeding. As soon as nauplii were observed in the digestive tract, they were delivered to all batches in order to improve survival of the maximum number of individuals. Growth in the batch fed only nauplii was better until 23 days post hatching (dph). The survival figure for larvae subjected to a short weaning period (3 days) at 17.5°C reached a maximum of 34% survival recorded at 34 days post initiation of weaning in 55-dph larvae. A long weaning (3 weeks) vs a short weaning (3 days) for 50-dph fish over a 56-day experimental period at 17.5°C resulted in better growth (6.4 g vs 2.9 g, respectively) and better survival (32.5% vs 6% respectively). The enrichment of nauplii did not show any difference in either growth or survival during a three-week experimental period. 50-dph fish fed live or frozen chironomids at 17.5°C during a 40-day period exhibited similar final weight (2.88 g and 2.87 g) and survival (98% and 98.5%). 2,000 hatchlings, 5,000 (~1 g) and 2,000 (~6.5 g) fingerlings were stocked in rivers.