Amy Qin, China Expands a Virus Dragnet; Seizing possible patients in two additional cities. New York Times, Feb 14, 2020 (front page).
Note: dragnet
ttps://en.wikipedia.org/wiki/Dragnet
(may refer to "a fishing net used in seine fishing")
lick "seine fishing," you will see seine weighed down, purpose of which is not bottom fishing https://en.wikipedia.org/wiki/Bottom_fishing
to harvest soles 比目魚, for example, but to prevent fish from escaping BELOW fishnet.