D.C. Mun. Regs. tit. 19, r. 19-1502
Fishing or taking fish or other aquatic organisms for commercial purposes is prohibited.
Except as otherwise permitted by these rules, a person shall fish only with rod, hook, and line, not to exceed three (3) lines in number and not having more than two (2) hooks to each line. Artificial lures or plugs with multiple or gang hooks are considered one unit.
The use of dip nets shall be prohibited, except that dip nets may be used for the capture of baitfish, gizzard shad, blueback herring, alewife, and in the landing of fish taken by angling, provided that the net does not exceed twenty-four inches (24") in diameter or nine square feet (9') in overall area. The use of dip nets in Rock Creek Park shall be prohibited under any circumstances, in conformance with section 1503.2.
The use of seine nets and cast nets shall be prohibited.
Snagging shall be prohibited, except for the capture of blueback herring, alewife, gizzard shad, and menhaden.
A person may operate eel traps provided the number of traps does not exceed five.
An eel trap operator shall attach the operator's angling license number to each trap and shall check each trap daily.
D.C. Mun. Regs. tit. 19, r. 19-1502