highly significantp < 0.01
T = 2; U -test, p = 1), OPD in sediment from exclusion treatment enclosures decreased from 32 mm ± 3 at T = 3 to 12 mm ± 2 (mean ± SE) at T = 5, exhibiting a 63% reduction and resulting in a highly significant difference between treatments (Mann–Whitney U -test; p < 0.01).