Table 1.
Comparison in biotic variables before (2012) and after (2015) the trawl ban in surveyed 28 sites in Hong Kong waters.
| Variables | 2012 | 2015 | t | n | P | ||
|---|---|---|---|---|---|---|---|
| Mean | S.D. | Mean | S.D. | ||||
| Total abundance | 253 | 508 | 848 | 1119 | −4.581 | 28 | <0.0001*** |
| Total biomass | 65.50 | 263.68 | 70.81 | 176.15 | −0.087 | 28 | 0.932 |
| Number of species | 27.5 | 18.3 | 48.3 | 26.0 | −6.839 | 28 | <0.0001*** |
| Margalef’s richness index, d | 5.33 | 2.85 | 7.30 | 3.51 | −5.179 | 28 | <0.0001*** |
| Pielou’s evenness index, J | 0.77 | 0.16 | 0.68 | 0.14 | 3.306 | 28 | 0.003** |
| Shannon–Wiener diversity index, H' | 3.38 | 1.13 | 3.61 | 1.27 | −1.304 | 28 | 0.203 |
| AZTI’s Marine Biotic Index, AMBI | 2.53 | 0.80 | 2.30 | 0.78 | 1.161 | 28 | 0.256 |
| Functional diversity | 2.46 | 0.77 | 2.46 | 0.77 | 0.052 | 28 | 0.959 |
| Functional groups | 11.6 | 5.4 | 14.8 | 5.7 | −4.402 | 28 | 0.0002*** |
| Collectors | 111.5 | 326.3 | 285.7 | 375.4 | −2.780 | 28 | 0.0098** |
| Burrowers | 45.7 | 150.8 | 72.7 | 96.4 | −0.816 | 28 | 0.422 |
| Carnivores | 37.0 | 40.3 | 228.5 | 341.1 | −3.238 | 28 | 0.003** |
| Surface deposit feeders | 3.3 | 9.1 | 84.2 | 159.1 | −2.822 | 28 | 0.008** |
| Omnivores | 34.4 | 89.6 | 30.0 | 68.3 | 0.632 | 28 | 0.533 |
| Suspension feeders | 21.7 | 60.3 | 146.4 | 500.3 | −1.319 | 28 | 0.198 |
| Discretely motile | 126.9 | 338.4 | 335.9 | 702.0 | −2.852 | 28 | 0.008** |
| Motile | 118.9 | 276.1 | 489.4 | 714.6 | −4.044 | 28 | 0.0004*** |
| Sessile | 7.6 | 16.9 | 22.2 | 28.6 | −2.943 | 28 | 0.007** |
Asterisks indicate significant differences, i.e.
**P < 0.01,
***P < 0.001.