However, the department is largely focused on the conservation and allotment of harvests of salt water fisheries on the Atlantic, Pacific and Arctic coasts of Canada.

Nunavut The department's responsibilities were described as follows: Sea-Coast and Inland Fisheries, Trinity Houses, Trinity Boards, Pilots, Decayed Pilots Funds, Beacons, Buoys, Lights and Lighthouses and their maintenance, Harbours, Ports, Piers, Wharves, Steamers and Vessels belonging to the Government of Canada, except gunboats or other vessels of war, harbour commissioners, harbour masters, classification of vessels, examination and granting of certificates of masters and mates, and others in the merchant service, shipping masters and shipping offices, inspection of steamboats and board of steamboat inspection, enquiries into causes of shipwrecks, establishment, regulation and maintenance of marine and seamen hospitals, and care of distressed seamen, and generally such matters as refer to the marine and navigation of Canada.

In its early days, one of the department's most active agencies was the operation of the Marine Service of Canada, which became the forerunner to the Canadian Coast Guard, with vessels dedicated to performing maintenance of buoys and lighthouses.

These ships and other chartered schooners and the like, would cruise the fishing grounds off the Atlantic and Pacific coasts, watching for violations within Canada's territorial sea, then only three nautical miles (6 km) from shore.

After a third reading, the bill received royal assent on May 4, 1910, and became the Naval Service Act, administered by the minister of marine and fisheries at the time.

[5] The program aims to ensure the conservation and sustainable use of Canada's aquatic resources and the protection of species at risk, fish habitat, and oceans, not always successfully.

[6] C&P collaborates with a variety of domestic partners, including the Canadian Coast Guard, other federal departments, other levels of government, industry, First Nations communities, recreational fishing groups, and others.

C&P promotes compliance with legislation, regulations and management measures through education and shared stewardship initiatives; conducts monitoring, control, and surveillance activities using surface vessels, aerial surveillance aircraft and land patrols; and manages major cases and special investigations.

DFO's chief fishery officer is the Director General, Conservation & Protection; as of April 2019, the incumbent is Darren Goetze.