Molluscan Research 25(1):
1-8; published 22 April 2005
Copyright © The
Malacological Society of Australasia
The influence of culture
conditions on the growth and biochemical composition of an
algal feed for
juvenile greenlip abalone (Haliotis
laevigata)
D. WATSON*1, S. DAUME3,
J. PRINCE2, L. BEAZLEY2 AND B. KNOTT2
1
The University of Western Australia, M090 Botany, 35 Stirling Highway,
Crawley, W.A. 6009 Australia
2 The University of Western Australia, M092 Zoology, 35
Stirling Highway, Crawley, W.A. 6009 Australia
3 Department of Fisheries, Research Division, PO Box 20
North Beach, W.A. 6920 Australia
*Corresponding author: dwatson@plants.uwa.edu.au
Abstract
The diatom Navicula jeffreyi was
cultured in seawater media of low, standard or high nitrate content
(2.47, 12.35 and 24.71 mg NO3-N
L-1,
respectively) in high (22 ± 3 mmol
photons/m2/s)
and low (4.7 ± 0.8 mmol
photons/m2/s)
light conditions. The growth, survival and grazing rates of juvenile Haliotis
laevigata Donovan, 1808 were monitored in response to the density
and biochemical composition of N. jeffreyi cultured in each of
the six treatments. Navicula
jeffreyi Hallegraeff et Burford grown in high light had a
proportionally lower protein content and a higher carbohydrate and fat
content (22 ± 0.6%; 17.6 ±
1.5%; 7.5 ± 0.7%,
respectively) compared to the content of diatoms grown in low light
(30 ± 0.6%; 14.3 ±
2.5%; 4.7 ± 1%,
respectively). Under low light, the carbohydrate content of N.
jeffreyi was marginally higher in low nitrate treatments (17%)
compared to standard (14%) and high (12%) nitrate. Juveniles grazed a
larger number of diatoms when the protein content of the diatoms was
low, possibly compensating for the lower protein levels. In high
light, dense N. jeffreyi biofilms produced elevated pH levels
which most likely resulted in the mortality of a large number of
juvenile H. laevigata. This study indicates that changes in
light intensity and nitrate concentration under which the diatom N.
jeffreyi were cultured, affected the growth, survival and grazing
rates of juvenile H. laevigata.
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