History of Bait

Bait is the consumable used for Fishing, introduced in Season of the Deep. Every cast costs one bait, and you can hold up to 500.

Acquisition

Bait is rewarded for Salvage, Deep Dive and playlist activities, public events, patrols and collecting planetary materials (one per material). TheGamer says a Salvage gives up to 16; another outlet lists 18 for Salvage, 15 for Deep Dives, six for public events and two for patrols, so exact amounts may have changed. Hawthorne gives ten free bait after the first fishing quest. Fishing without bait lowers the odds of better catches, as seen on Chiron's Carp.