If you spend much time fishing bridges at night, then the Yo-Zuri Mag Minnow should be your go-to lure, because it’s simple to use, represents a variety of baitfish and is super effective. Living in South Florida, the lights from the bridges draw a lot of snook and tarpon, which are my main targets. As a rule, both species like to hunt the shadow lines cast by the bridge on the up-current side of the structure, although tarpon will regularly work the down-current side as well.
The fish like to station on the dark side of the shadow line so mullet swimming with the current won’t see them. When the mullet traveling in the lighted areas hit the dark, shadowed sections they tend to be blinded for a few seconds and often slow down or stop. That’s when the fish strike.
The key for fishing shadow lines is to position your boat parallel to the shadow line you plan to fish, then cast parallel to the bridge but 10 to 20 feet up-current of the shadow line, allowing you to slowly swim the lure into the shadows. You can mix up the length of the cast or the distance from the shadow line to make the lure swim through the area in different locations.
The majority of the time I fish a Mag Minnow I just cast it out and reel in slowly back to the boat, giving it no action so it looks like a hapless baitfish just swimming along. Every few casts I’ll change it up and retrieve the lure with a stop and go action, ripping it along with a sweep of the rod and then letting the bait sit stationary for a second or two before moving it again. That will sometimes get reaction bites from fish that aren’t normally feeding.
Since the lighting on bridges is man-made and not natural, there’s a tendency for your leaders to reflect more light than during the daylight hours, so I always use Yo-Zuri fluorocarbon leader. I’ll also drop down in leader size from 50 pound test to 30 or 40 pound test to get more bites.