# From Feed to Fish--Nutrients' Fate in Aquaculture Systems
## 3 Results
### Fislpond and Cultivation Characteristics
#### 3.3.2. Inlet Water  
Of the twenty-three papers, five did not report the water source, and although they were included in the budget, the main water source was not specified in one of the studies that reported the budget [17]. Nonetheless, in this case, the contribution of inlet water to the budget was less than 5% of the total inputs (Table 2). Particularly, studies that reported a substantial contribution of inlet water to the total input mentioned the specific water source. Studies on Brazilian fishponds reported a high share of the nutrients being supplied by the inlet water, along with which source was a reservoir that received effluents from \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Reference** & **Location** & **C (\%)** & **kg ha\({}^{-1}\) d\({}^{-1}\)** & **N (\%)** & **kg ha\({}^{-1}\) d\({}^{-1}\)** & **P (\%)** & **kg ha\({}^{-1}\) d\({}^{-1}\)** \\ \hline
[15] & China & n.r. & n.r. & n.r. & n.r. & 0.9 & 0.001 \\
[16] & USA & 0 & 0 & n.r. & n.r. & n.r. & n.r. \\
[18] & India & 0.5 & 0.06 & 0.08 & 0.001 & 0.07 & 0.003 \\
[21] & Brazil & n.r. & n.r. & 0.06 & 0.002 & n.r. & n.r. \\
[22] & Brazil & n.r. & n.r. & n.r. & n.r. & 0.5 & 0.004 \\
[24] & Brazil & n.r. & n.r. & 0.9 & 0.02 & n.r. & n.r. \\
[25] & Brazil & 0.6 & 0.19 & n.r. & n.r. & n.r. & n.r. \\
[26] & Brazil & n.r. & n.r. & n.r. & n.r. & 0.5 & 0.002 \\
[28] & USA & n.r. & n.r. & 4 & 0.07 & n.r. & n.r. \\
[29] & Homduras & n.r. & n.r. & 0.6 & 0.01 & 0.1 & 0.001 \\
[30] & China & n.r. & n.r. & 0.5 & 0.009 & 0.05 & 0.0002 \\
[31] & China & 0.06 & 0.05 & 0.11 & 0.01 & 0.08 & 0.001 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Contribution of precipitation to the total input of carbon, nitrogen, and phosphorus and their average supply rates during the study period (kg ha\({}^{-1}\) d\({}^{-1}\)). Values shown in the table are the mean of the values reported in the assessed papers. n.r. : not reported. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Reference** & **Water sources** & **C (\%)** & **kg ha\({}^{-1}\) d\({}^{-1}\)** & **N (\%)** & **kg ha\({}^{-1}\) d\({}^{-1}\)** & **P (\%)** & **kg ha\({}^{-1}\) d\({}^{-1}\)** \\ \hline
[13] & Irrigation canals, precipitation, and infiltration * & 7 & 4.3 & 54 & 4.6 & 10 & 0.3 \\
[14] & Stream & n.r. & n.r. & n.r. & n.r. & 0.3 & 0.001 \\
[16] & Precipitation, groundwater, and runoff & 0 & 0 & n.r. & n.r. & n.r. & n.r. \\
[17] & n.r. & 0.5 & 0.06 & 0.1 & 0.0009 & 0.07 & 0.0003 \\
[21] & Reservoir & n.r. & n.r. & 29 & 1 & n.r. & n.r. \\
[22] & Reservoir & n.r. & n.r. & n.r. & n.r. & 26 & 0.19 \\
[24] & Reservoir & n.r. & n.r. & 58 & 1 & n.r. & n.r. \\
[25] & Reservoir & 32 & 10 & n.r. & n.r. & n.r. & n.r. \\
[26] & Reservoir & n.r. & n.r. & n.r. & 37 & 0.11 \\
[27] & Reservoir & n.r. & n.r. & 6 & 0.6 & 0.1 & 0.004 \\
[28] & Main source n.r. and precipitation & n.r. & n.r. & 7 & 0.12 & n.r. & n.r. \\
[29] & Main source n.r. and precipitation & n.r. & n.r. & 4 & 0.06 & 4 & 0.03 \\
[30] & Main source n.r. and precipitation & n.r. & n.r. & 1 & 0.01 & 0.4 & 0.001 \\
[31] & Main source n.r. and precipitation & 0.45 & 0.3 & 1.7 & 0.17 & 1.4 & 0.02 \\
[32] & Watershed & n.r. & n.r. & n.r. & n.r. & 72 & 0.0001 \\
[33] & Effluents from fish culture & n.r. & n.r. & 75 & 1.3 & 55 & 0.12 \\
[34] & Water from fishpond & n.r. & n.r. & n.r. & n.r. & 1 & 0.01 \\
[35] & Effluents from fish culture & n.r. & n.r. & 1 & 0.2 & 0.2 & 0.006 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Contribution of inlet water to the total input of carbon, nitrogen, and phosphorus, along with their average supply rates during the study period (kg ha\({}^{-1}\) d\({}^{-1}\)). Values shown in the table are the mean of the values reported in the assessed papers. n.r. : not reported. other animals' cultivation. Thus, for phosphorus, there were shares of 26% [22] to 37% [26]; for nitrogen, there were shares of 29% [21] and 58% and [24]; and for carbon, 32% were found [25].