Evaluation of partial
substitution of live algae with dried Tetraselmis for larval
rearing of black-lip pearl oyster, Pinctada margaritifera (L.)
M.S. Doroudi, P.C. Southgate, R.J. Mayer-2002
Aquaculture
International, 10(4): 265-277
Abstract:
Experiments were conducted with larvae of the
black-lip pearl oyster, Pinctada margaritifera fed on a regime of
living algae (an equal mixture of Tahitian Isochrysis aff. galbana
and Pavlova salina) either partially or completely substituted with
heterotrophically grown spray-dried algae (Tetraselmis suecica).
Two experiments were conducted; in the first, 1-day old larvae were cultured
for 13 days and, in the second, 13 days old larvae were culture for 7 days.
In both experiments larvae were fed the following proportions of live algae
(LA) and dried Tetraselmis (DT); (1) 100% LA, (2) 75% LA + 25% DT,
(3) 50% LA + 50% DT, (4) 25% LA + 75% DT; and (5) 100% DT. The optimal diets
for maximum larval growth were 100% LA and 75% LA + 25% DT resulting in
larvae with a mean shell length (SL) of 132 ±
3.8 and 131 ± 2.7 µm,
respectively, at day 13. This showed that 25% substitution of live
micro-algae with DT is possible without affecting growth of P.
margaritifera larvae of less than 150 µm
SL. There was no significant difference in survival of P. margaritifera
larvae fed 100% LA, 75% LA + 25% DT and 50% LA + 50% DT over a period of 13
days. Highest survival (43.7%) occurred in larvae fed 100% DT while lowest
(approximately 18%) occurred in controls (50% live micro-algae and unfed)
during the first experiment. The result of the second experiment indicated
that with increasing size, larvae are capable of accepting a higher
proportion of dried Tetraselmis in their diet. There were no
significant differences in larval growth or survival, between treatments
where LA was partially and completely substituted diets with DT.
(School
of Marine Biology and Aquaculture, James Cook University, Townsville,
Queensland 4811, Australia Corresponding author: NSW Fisheries, C-Murray
Irrigation, Wakool 2710, NSW, Australia, E-mail: doroudim@fisheries.nsw.gov.au)