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Environmental parameters in the Caspian Sea from 1996 to 2017_
| Variable | Mean | SD | Minimum | Maximum |
|---|---|---|---|---|
| 1Precipitation, cm | 125.8 | 20.27 | 85.3 | 153.9 |
| 1Evaporation, cm | 42.9 | 3.38 | 34.9 | 48.8 |
| 2SST_Mar, °C | 11.4 | 0.77 | 10.2 | 12.6 |
| 2SST_Apr, °C | 14.2 | 1.19 | 12.1 | 17.6 |
| 2SST_Oct, °C | 22.7 | 0.79 | 21.6 | 24.2 |
| 2SST_Aug, °C | 28.2 | 0.99 | 25.3 | 29.7 |
| 2SST, °C | 19.2 | 0.42 | 18.3 | 20.2 |
| 3SSL, m | −26.4 | 0.34 | −27.1 | −26.1 |
| 3Volga discharge, km3 | 233.3 | 33.96 | 176.2 | 283.5 |
| 3Iran's rivers discharge, km3 | 3.79 | 1.58 | 1.98 | 7.50 |
| 2GTA | 1.14 | 0.82 | −0.88 | 2.42 |
| 4EAWR | −0.20 | 0.94 | −2.12 | 2.11 |
| 4NAO | −0.13 | 0.38 | −1.29 | 0.40 |
Relationship between environmental variables and diversity index, most abundant fish species (species with a percentage value higher than 1%) in the Caspian Sea_
| Variables | AIC | RSS | R2 | |
|---|---|---|---|---|
| Community | Year, PR, SST_Apr, SSL, SST, GTA, IRD, VD | 83.0 | 422.7 | 0.803 |
| Shannon diversity | Year, SSL, IRD | −86.3 | 0.302 | 0.867 |
| Rutilus kutum | Year, PR, SST_Apr, SSL, SST, VD | −64.0 | 0.634 | 0.666 |
| Cyprinus carpio | Year, PR, SSL, SST, SST_Aug, IRD, VD | −30.9 | 2.615 | 0.770 |
| Rutilus rutilus | Year, PR, SST_Mar, SST_Apr, SST_Oct, SSL, SST, SST_Aug, EAWR, VD, NAO | −95.1 | 0.098 | 0.975 |
| Chelon aurata | Year, SST_Oct, EV, SSL, SST, GTA, EAWR, VD, NAO | −66.8 | 0.388 | 0.832 |
| Chelon saliens | Year, PR, SST_Oct, SSL, SST, GTA, EAWR, VD, NAO | −57.9 | 0.638 | 0.912 |
Results of the DistLM model, containing the Sum of Square (SS), Pseudo-F statistic, p-value, and proportional total variance_
| Variable | SS | Pseudo-F | P-value | Proportion % |
|---|---|---|---|---|
| Year | 1007.0 | 17.70 | 0.001 | 46.94 |
| SSL | 730.1 | 10.32 | 0.001 | 34.04 |
| VD | 321.5 | 3.53 | 0.013 | 14.99 |
| IRD | 281.2 | 3.02 | 0.032 | 13.11 |
| EAWR | 273.5 | 2.92 | 0.040 | 12.75 |
| EV | 192.0 | 1.97 | 0.111 | 8.95 |
| SST_Mar | 169.8 | 1.72 | 0.155 | 7.91 |
| SST | 146.0 | 1.46 | 0.208 | 6.81 |
| SST_Aug | 96.2 | 0.94 | 0.433 | 4.48 |
| NAO | 96.1 | 0.94 | 0.430 | 4.48 |
| PR | 86.8 | 0.84 | 0.486 | 4.04 |
| SST_Apr | 85.4 | 0.83 | 0.491 | 3.98 |
| SST_Oct | 67.9 | 0.65 | 0.602 | 3.16 |
| GTA | 58.1 | 0.56 | 0.688 | 2.71 |
Mean annual catch number per unit effort (NPUE) and catch per unit effort (kg/beach seine, CPUE, ± SE) of commercial bony fish in the Caspian Sea in 1996–2017_
| Family | Species | NPUE (number) | CPUE (kg/beach seine) | ||||
|---|---|---|---|---|---|---|---|
| Mean | SE | % | Mean | SE | % | ||
| Cyprinidae | Rutilus kutum | 168.20 | 12.97 | 47.14 | 118.32 | 9.37 | 62.65 |
| Cyprinus carpio | 16.01 | 7.12 | 4.49 | 9.38 | 3.35 | 4.97 | |
| Rutilus rutilus | 4.45 | 1.21 | 1.25 | 0.70 | 0.20 | 0.37 | |
| Vimba vimba | 3.22 | 0.81 | 0.90 | 0.44 | 0.11 | 0.23 | |
| Alburnus chalcoides | 1.05 | 0.26 | 0.29 | 0.21 | 0.05 | 0.11 | |
| Leuciscus aspius | 0.06 | 0.02 | 0.02 | 0.04 | 0.01 | 0.02 | |
| Abramis brama | 0.60 | 0.14 | 0.17 | 0.12 | 0.03 | 0.06 | |
| Luciobarbus capito | 0.14 | 0.03 | 0.04 | 0.10 | 0.02 | 0.06 | |
| Mugilidae | Chelon aurata | 145.61 | 11.79 | 40.80 | 55.41 | 4.67 | 29.34 |
| Chelon saliens | 16.09 | 4.41 | 4.51 | 3.57 | 0.98 | 1.89 | |
| Percidae | Sander lucioperca | 1.34 | 0.34 | 0.38 | 0.50 | 0.13 | 0.27 |
| Salmonidae | Salmo caspius | 0.02 | 0.01 | 0.01 | 0.05 | 0.01 | 0.03 |
| Siluridae | Esox lucius | 0.05 | 0.02 | 0.01 | 0.02 | 0.01 | 0.01 |