The fishers also shall mourn, and all they that cast angle into the brooks shall lament, and they that spread nets upon the waters shall languish.
The fishers also shall mourn. The Nile was famed for fish (Numbers 11:5). Numbers would be thrown out of employment by the failure of fish.
And all they that cast angle - a hook. Used in "the brooks," or canals, as the 'net' was in "the waters" of the river itself. Still the Hebrew for "brooks" is literally, 'into the river;' bay`or (H2975).