51813_Sturgeon biodioversity an.PDF

Rearing of larvae

Larvae were fed mainly with live nauplii ofArtemia
salinaand other zooplankton or frozen natural Cood
(chironomid larvae orTubifexsp.) alone or mixed
with chicken egg yolk, beef spleen, and an experi-
mental artificial diet made of beef liver and yeast
(Kaushik et al. 1986). Water temperature for rear-
ing was approximately 17°C.

Adoptation of wild immature fish to farm conditions

We first tested direct adaptation of large juveniles

fish from brackish (15 to 20‰) to fresh water. The

analysis of published data (Magnin 1962) and use of

the updated growth information (Rochard & Jat-

teau 1991) imply a possible successful adaptation of

sturgeon≥ 105 cm TL to freshwater. Our experi-

ments used riverine or well water at a constant ten-

perature of 18°C. Methods for long term acclimati-

zation of wild immature European Atlantic stur-

geon to farm conditions were based on previous

success with other sturgeon species, A. naccarii

(Arlati et al. 1988),A. transmontanus(Struffeneg-

ger 1992), andH. huso(Goncharov personal coin-

munication).

Communication with the public

We printed and distributed booklets and posters

aboutA. sturioto fishermen of the Atlantic coast of

France. We mailed more specific materials to all

French fisheries administrators, organizations of

fishermen, and to French and western European

fish research laboratories. We organized local

meetings to explain our goals and previous results,

and established an information network. To in-

media (local, regional, and national newspapers; ra-

dio and television). To roster scientific cooperation,

we organized the first international symposium on

Figure 3. Accidental captures of A. sturio between 1987 and 1993, crease public awareness, we collaborated with the
showing numbers of tagged versus non-taggsd individuals re-
ported.

stated operations. the water temperature was sturgeon, held in Bordeaux in 1989 (Williot 1991).
~17°C.

Results and discussion

Current status of the population

Figure 1 summarizes background information

necessary to understand the Gironde population of

Acipenser sturio, which has currently the only

known spawning stock of this species in western Eu-

rope. During its sea life,A. sturiooccurs over a wide

range (Figure 2), from the Bay of Biscay to the Bris-

se

E+

Figure 4. Changes in the age structure of juvenileA. sturioin the

Gironde Estuary between 1985 and 1992. Juvenile European At-

lantic sturgeon move from the sea into the estuary (April-Sep-

tember).