Table 3.
Critical factors for certain KPIs in the different hatcheries, as indicated by classification tree models.
| KPI | Potentially critical factor | Rel | nH | nL | Cor. Clas. (%) | Sign |
|---|---|---|---|---|---|---|
| Pug | Total Rotifers (3–35 dph) | N | 10 | 9 | 89.5 | ** |
| Artemia instar II (15–36 dph) | N | 10 | 9 | 94.7 | ** | |
| Artemia instar II (26–36 dph) | N | 10 | 9 | 94.7 | ** | |
| Artemia instar II (26–36 dph) | N | 9 | 8 | 100.0 | ** | |
| Artemia instar II (30 dph) | N | 10 | 9 | 89.5 | ** | |
| SD of temperature (10–14 dph) | N | 9 | 8 | 100.0 | *** | |
| Cdf | O2 cum. differences (daily, 11–20 dph) | P | 9 | 8 | 100.0 | *** |
| O2 SD (10–14 dph) | P | 9 | 8 | 100.0 | *** | |
| Temperature cum. differences (daily, 0–10 dph) | N | 9 | 8 | 100.0 | *** | |
| Artemia instar II (15–36 dph) | N | 9 | 8 | 100.0 | ** | |
| Age @ Weaning onset (dph) | N | 9 | 8 | 100.0 | *** | |
| Rotifer adjustment-levels | N | 9 | 8 | 100.0 | *** | |
| SBS | Total Dry Feed (21–25 dph) | N | 14 | 5 | 100.0 | *** |
| Artemia instar II (15–36 dph) | P | 8 | 9 | 82.4 | – | |
| V | SD of temperature (25–29 dph) | P | 10 | 8 | 88.9 | ** |
| Sur | Rotifers (3 dph) | P | 9 | 10 | 100.0 | ** |
| Artemia instar II (15–36 dph) | P | 9 | 8 | 94.1 | *** | |
| Age @ Weaning onset (dph) | P | 9 | 8 | 94.1 | *** | |
| Initial Stocking Density | N | 9 | 8 | 100.0 | *** | |
| SD of temperature (0–4 dph) | N | 9 | 8 | 88.2 | ** | |
| SD of temperature (5–9 dph) | N | 9 | 9 | 94.4 | ** | |
| SD of temperature (15–19 dph) | N | 9 | 8 | 88.2 | * | |
| Artemia instar I (product name) | 9 | 8 | 88.2 | - | ||
| Air-diffusers (number) | N | 12 | 8 | 100.0 | *** | |
| Spawning temperature | P | 12 | 8 | 95.0 | *** |
“Rel” column indicates the type of relationship between KPIs and critical factors (P, positive; N, negative), “nH” and “nL” columns the count of cases with high and low quality respectively, “Cor. Clas.” the % of correct classifications, and “Sign.” the significance of the difference in the critical factors between the nH and nL groups (*p < 0.05; **p < 0.01; ***p < 0.001). Analyses were performed separately for the different hatcheries. Cdf, caudal-fin abnormalities. Pug, pugheadness. SBS, dorsal-fin abnormalities. Sur, survival rate at 26–70 dph. V, vertebral abnormalities. KPI to critical factor association is purely statistically based on the specific data provided. They can serve only in building hypotheses to be tested by each hatchery.