Broodstock conditioning of
the oyster Crassostrea gigas: origin and temperature effect
J.
Chávez-Villalba, J. Pommier, J. Andriamiseza, S. Pouvreau, J. Barret, J.-C.
Cochard, M. Le Pennec-2002
Aquaculture, 214(1-4) : 115-130
Abstract:
Broodstock conditioning of the pacific oyster Crassostrea
gigas (Thunberg) was examined in the laboratory under controlled
conditions. Three experiments were undertaken to determine (i) the effect of
the origin on gametogenesis, (ii) the time necessary to obtain the first
mature oocytes in standard conditioning procedures, and (iii) the impact of
different conditioning temperatures (16, 19, 22 and 25 °C) on
gametogenesis. Oocyte size was used to identify mature oocytes. Significant
differences among populations were observed in the number of mature oocytes
produced. Only the oysters from northern locations (Normandy and Brittany)
reached the mature stage by the end of the standard conditioning. Concerning
the effect of different temperatures during conditioning, the first mature
oocytes were detected (absolute days) by the 27th day at 16 °C, 23rd day at
19 °C, 19th day at 22 °C and 22nd day at 25 °C. This information was
applied to fit a logistic model to predict oocyte growth using temperature
and time as main affecting parameters; D=Dmax/(1+ae-kt)
with D––oocyte diameter at time t (µm), Dmax––the
asymptotic oocyte diameter (µm), a––adjustment parameter, k––slope
of the curve during growing stage and t––time (days). The model
fit consistently with values achieved at 16, 19 and 22 °C. The results
obtained during this study could be used to improve conditioning procedures
for C. gigas.
(U.M.R.
C.N.R.S. 6539, Institut Universitaire Européen de la Mer, 29280 Plouzané,
France, Tel.: +33-02-98-22-43-96, e-mail of J.-C. Cochard : Jean.Claude.Cochard@ifremer.fr)