The use of Artemia
biomass sampling to predict cyst yields in culture ponds
P.
Baert, Nguyen Thi Ngoc Anh, A. Burch, P. Sorgeloos-2002
Hydrobiologia, 477 (1-3): 149-153
Abstract:
The possibility of using biomass volume (= mean
biomass present in the pond.week -1) to predict the total amount
of harvestable cysts (= kg wet weight collected. week -1)
produced in a culture pond by an Artemia franciscana population
using a mixed model regression was evaluated for two different sampling
methods; horizontal transects and vertical point samples. For transects, the
following equation was found: `log (0.01 + cyst yields) = –2.05
+ 0.025*(biomass volume)' with F(1, 4.87) =
8.83 and p = 0.032. For the point samples, the regression was also
significant with F(1, 55.2) = 13.62 and p =
0.0005 for following equation: `log (0.01 + cyst yield) = –3.613
+ 0.021*(biomass volume). As pond effect and interaction terms
did not significantly explain a significant portion of the variance for
either of the sampling methods (Transects: pond: F(3, 14.3)
= 2.48; p = 0.103; pond*biomass volume: F(3,
3.61) = 4.63; p = 0.0976; Point samples: pond: F(3,
44.5) = 0.00; p = 0.999; pond*biomass volume: F(3,
44.2) = 0.11; p = 0.954 ), the variable pond (repeated
measurement factor) was not included in the final calculations for the
regression equations. Although a combination of factors influences the
equation, the high significance levels of the regression indicate biomass
volume can be safely used to predict production trends. The low investment
requirements of this method make it especially attractive for on farm use,
where correctly determining the point of cyst decline will help farmers to
allocate resources where needed.
(Provinciaal
Natuurcentrum, Het Groene Huis, Domein Bokrijk, Genk, Belgium)