| Treatment | % of total # of commercial clamsa harvested | % of total wt of commercial clams harvested | Harvest efficiency (seconds clam−1) |
| Z. japonica | 88 | 87 | 3.4 |
| No Z. japonica | 93 | 95 | 2.6 |
| T-test significance | 0.04 | 0.05 | 0.1 |