ABSTRACT The hard clam (Meretrix lusoria) is one of the most important cultured molluscs in Taiwan. Although it is mainly cultured in ponds and supplemental feeding of artificial feed is commonly practiced, no scientific information on its preferred foods and appropriate feeding strategies are available. Six diets: fishmeal (F), soybean meal (S), commercial hard clam feed (C), microalgae Tetraselmis chui (T) and Nannochloropsis oculata (N) and bread yeast (Y), were fed to hard clams. ...
<5 [micro]m, every 5 [micro]m from 6-30 [micro]m and><75%). Algal cells, such as phytoplankton and other particles in the size range 3-8 [micro]m were efficiently retained (70% to 100% retention) by the clam (Sobral & Widdows 2000). The studies mentioned earlier concluded that filtration retention efficiency increased with increasing particle size from 0.2-8 [micro]m. In our study, because the particle size of diets varied over a wider range, 4 [micro]m to 19 [micro]m, the overall ranking of filtration rates for the diets (S>
<0.01
Error 34
Total
TABLE 2. Main effects of 6 diets, 2 clam sizes, their interactions and
5 orthogonal contrasts for diets on hard clam pseudofeces production.
SV Mean df SS
Model 11 27.48
Diet 5 24.69
Shape (Reg. vs. Irreg.)
(N, T, Y vs. C, F, S) 1.42 vs. 1.39 1 0.49
Reg. (Algae vs. Yeast)
(N, T vs. Y) 0.95 vs. 2.37 1 20.15
Algae (Nano. vs. Tetra.)
(N vs. T) 0.73 vs. 1.17 1 0.79
Irreg. (Mixture vs. Single)
(C vs. F, S) 0.90 vs. 1.65 1 2.97
Single (Soy. vs. Fish.)
(S vs. F) 1.78 vs. 1.51 1 0.28
Clam size 1 1.49
Clam size x Diet 5 1.30
Error 36 5.98
Corrected Total 47 33.46
SV MS F P>