Ecological intensification in multi-trophic aquaculture ponds: an experimental approach

Open Access

Table 4

Means of chemical, physical and biological indicators of the water in ponds for each treatment during the experiment.

	Extensive		Semi-intensive		Coupled

Indicator	Mean	SD¹	Mean	SD¹	Mean	SD¹	Significance²
Temperature (°C)	20.1	6.3	19.9	9.0	18.8	5.7	NS
pH	8.74^b	0.45	7.74^a	0.19	8.08^a	0.66	^**
Dissolved oxygen (mg · l⁻¹)	13.9^b	2.8	9.7^a	1.3	10.6^a	3.0	^**
Oxygen saturation (%)	155^b	39	98^a	26	116^a	36	^**
Conductivity (mS · cm⁻¹)	346	39	326	44	333	53	NS
Water transparency (cm)	28^a	8	11^b	10	25^a	11	^**
TN (mg · l⁻¹)	2.65^a	1.64	3.63^b	1.29	2.90^a	1.51	^*
TP (mg · l⁻¹)	0.13^ab	0.08	0.19^a	0.10	0.14^b	0.16	^**
Chlorophyll-a (μg · l⁻¹)³	19.2^a	8.5	65.1^a	46.2	7.2^b	7.7	^**
Total chlorophyll (μg · l⁻¹)⁴	123.9^a	74.1	134.3^a	73.0	28.2^b	18.9	^**
Blue chlorophyll (%)⁴	14^a	8	16a	9	1^b	2	^**
Green chlorophyll (%)⁴	56	29	63	26	65	23	NS
Brown chlorophyll (%)⁴	30	23	21	23	34	24	NS

Standard deviation.

Significance levels: **P <0.01, *P <0.05. Same letters in each column indicate no significant differences at the P <0.05 level.

From March to June.

⁴

From July to November.

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