(unimodal populationstructure,decline in occa-
sionalmarinecatches, increasedgrowthrates, and
non-motile sperm) aresymptoms of the dramatic
decline ofthis species. We metwith manydifficul-
ties (inability for thefemales to achievereproduc-
tivematuration incaptivity,feeding oflarvae, and
adaptation tofarmcondition).^2
Fourmainproblemsmust be solvedfor successful
restoration. Thefirst isobtainingbroodstock and
producingA. sturiofor restocking. Thisinvolves de-
termining thebestmethods ofcapture andtrans-
portation of wild fish to our research station, assess-
ment ofgoodconditions forshort andlong term ac-
climatization to farm conditions, maturation of
broodstock emphasizing water temperature, im-
proving reproduction methods for females and
males, production of juveniles, preparation of juve-
nilesbeforerelease (counting,tagging,transport),
release offish, and finally, in casematurewild
spawningfish arecaught, experimentsspanning ar-
tificialstripping to release ofjuveniles. The second
problem isincreasingnatural reproduction ofA.
sturio .We plan to study spawning grounds in order
to be able toimprove thosewhich aredegraded and
to createartificialones, as has alreadybeendone
elsewhere(Vlasenko1974,Gendron1988). The
thirdproblem isincreasing ourbasicknowledge of
the biology andstatus of the present population,
withspecial emphasis onits distribution. migration,
and structures.Fourth,biologists involved in the
restorationprogrammustattract the attention of.
and educate, thepublicabout the currentcondition
of the species.
It is often difficult toobtainfinancialsupport be-
cause the effectiveness ofrestorationprograms can
be estimatedonly on alongtermbasis.But, from a
longtermfinancialpoint ofview it hasalready been
demonstratedthat‘themanagement of endangered
species is intrinsically apolicy oflossminimization’
(Point1991). Suchawareness must bepromoted.
Because allsturgeonspecies aremore orless en-
dangered, andbecausetheycrossmanyinterna-
tionalboundaries, theirmanagement needs inter-
national cooperation and investment.weight, thisindividualregainedweight, butnever
recovered its naturalfeeding behavior.
Theseobservationsshowthat wemustminimize
stresses tosuccessfullyadaptfish to farmcondi-
tions. In1993, weusedlarger tanks (3 and 4 in dia-
meter)suppliedwith low salinity(5‰)thermoregu-
lated(18°C) water in darkness tokeepfishcalm.
Soonafter thearrival offish, salinity wasslowly
lowered to 0‰.Each tank ran as aclosedsystem in
whichnitrogencompounds, pH, andtemperature
werecontrolled. Thebottom of onetank was cov-
ered with 10 cm depth of 8–10 mm gravel. Two Fish
caught in mid-August werestocked into one tank
and two othersinto the second tank in lateSeptem-
ber. Theirsizes (TL =105.8 + 1.2 c m W = 5.4 ± 0.2
kg) wereclose to thegoal of < 105 cm TL. Thefish
were fed shrimps,mostlyfrozenPalaemonetes vari-
ans, Crangoncrangon,andPalaemon longirostris,
and whenavailable,livePalaemonlongirositis.
All fourfishcaught in 1993 were still alive in1994:
threebegan to eatshrimp after 160days, andafter
200 days, thelast individualfed.During theperiod
of starvation theylostabout 20% of theirbody
weight.Theywere progressivelyweanedonto pel-
lets, but shrimp remained the preferred food.
Whatever the food, theirconsumption isirregular,
and we did not find any relationshipbetweenfeed-
ing and the two types oftankbottom.
We suggestthatquickadaptation lofreshwater
of fish ≥ 105 cm is possible but that normal food in-
take is neededwithin 5.5 to 6.5months. In the fu-
ture,betterresults may beobtained byreducing all
possiblecauses of stress. Weintend to improve
catch, transport, andstocking conditions,particu-
larly using brackishwater(15‰)untilfishbegin to
feed andonly thereafterbegin thetransfer tofresh
water.^2
Restorationprogram forA. sturioBiologicalfeatures ofA. sturioin westernEurope(^2) Several ofthese problemsmeresolvedduring theI995season,
whenCemagrefsuccessfullycapt uredandartificiallystripped
adults andsubsequentlystockedjuvenilesinto theGironde sys-
tem (editors note, March, 1996