One of the most important problems faced by harbors and fishery harbors is the shoaling of their basins by sediment, because of the presence of coastal structures. As a result of shoaling, these structures very often face difficulties in fulfilling their functions, and sometimes it is impossible for vessels to enter their basins. Because of this, it has become compulsory to dredge harbor basins, an operation that requires a large amount of time and money. In this paper, the shoaling processes of fishery harbors is studied and the effects of main and secondary parameters (length, location, and so on), on fishery harbor shoaling, are researched in a physical model. Four regions of fishery harbors, in which the shoaling problem is dominant, are determined and the relation between shoaling amounts and breakwater parameters is empirically studied. It is believed that by taking into consideration the results of this study, it may be possible to reduce the shoaling amounts and dredging expenditures of fishery harbors (and probably of harbors too).