February 15-18, 2009 Washington State Convention Center Seattle ...

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EVALUATION OF SUBSTRATES IN BIOLOGICAL FILTERS FOR REARING PACIFIC
WHITE SHRIMP Litopenaeus vannamei IN CLOSED SYSTEMS
Mario Hernández-Acosta, Abundio González-González, Gilberto Gutiérrez-Salazar, Francisco M Guzmán-Saenz,
Jorge Loredo-Osti, Pablo González-Alanis and Kevin Fitzsimmons
Environmental Research laboratory
University of Arizona
2601 E. Airport Dr.
Tucson, Az 85706 USA
mariohdz@email.arizona.edu
The use of Biofilters to control water quality for long periods, offers the possibility of commercially producing marine organisms
at inland sites, avoiding problems such as environmental contamination. Recirculating water systems require the use
of a denitrification process to keep survival and ammonium and nitrate levels within acceptable ranges in order to insure the
cultivated marine organism’s development. Biofilters are considered as the most important factor for water treatment in a
recirculating system; their purpose is to provide a substrate to let probiotic bacteria grow. The development of such biofilters
has focused on effectiveness and conserving a proper balance between ammonia production and removal. Six different biofiltration
treatments were used in this study. The two way analysis of variance shows significant differences in survival of shrimp.
The physical – chemical parameters such as: pH, N-NO 2 y N-NO 3 , were similar in all treatments (p > 0.05); but the DO, TAN,
N-NH 3 and CaCO 3 were statistically different (p < 0.05). The two best biofilter systems with regard to shrimp survival and
growth, present an opportunity to culture shrimp for long periods with cero water exchange
.
Treatments
1 2 3 4 5 6 p
Temp ( 0 C) 26.7 ± 0.66 26.7 ± 0.66 26.7 ± 0.66 26.7 ± 0.66 26.7 ± 0.66 26.7 ± 0.66 p > 0.05
DO (mg/L) 5.08 ± 0.31 5.05 ± 0.54 4.97 ± 0.37 4.75 ± 0.33 4.40 ± 0.49 4.50 ± 0.37 p < 0.05
pH 7.70 ± 0.11 7.70 ± 0.11 7.70 ± 0.11 7.72 ± 0.10 7.62 ± 0.16 7.68 ± 0.13 p > 0.05
TAN (mg/L) 0.125 ± 0.027 0.122 ± 0.045 0.100 ± 0.077 0.142 ± 0.097 0.063 ± 0.022 0.075 ± 0.042 p < 0.05
N-NH3 (mg/L) 0.0038 ±0.0017 0.0033 ±0.0015 0.0028 ±0.0022 0.0042 ±0.0029 0.0015 ±0.0006 0.0018 ±0.0012 p < 0.05
N-NO2 (mg/L) 0.375 ± 0.154 0.492 ± 0.246 0.300 ± 0.089 0.467 ± 0.266 0.292 ± 0.156 0.283 ± 0.264 p > 0.05
N-NO3 (mg/L) 7.3 ± 2.3 8.2 ± 2.2 7.7 ± 2.7 8.7 ± 2.1 8.8 ± 2.0 9.0 ± 2.4 p > 0.05
CaCO3 (mg/L) 248.7 ± 12.6 236.7 ± 26.3 219.0 ± 18.7 221.3 ± 19.5 192.7 ± 37.2 198.3 ± 31.4 p < 0.05
Salinity (ppt) 15 ± 0 15 ± 0 15 ± 0 15 ± 0 15 ± 0 15 ± 0 p > 0.05
Table 1.- Mean and standar deviation of the evaluated parameters during the experiment.