dredger

A dredger is a vessel or machine used for underwater excavation, primarily to maintain or deepen waterways, create new land, construct control works, or recover valuable subaqueous deposits. Dredges can be mechanical, like dipper or grab dredges, or hydraulic, using pumps to move material.12

In contrast, fishing vessels are designed for catching fish. While some fishing vessels are specialized, like lift-netters or those using drifting longlines, the term "dredger" in the context of fishing refers to vessels that use dredges to harvest shellfish from the seabed. These fishing dredgers often have shallow drafts and may be equipped with multiple booms for towing dredges, with sorting facilities on deck. They typically operate in sheltered, shallow waters.345