How do fishermen use strong lights to attract clupeid schools at night?

Fishermen exploit the natural behavior of clupeid schools—which typically migrate toward the surface at night—by using strong lights to congregate them. On moonless nights, these schools are attracted to beams of light, causing them to gather near the surface where they can be more easily captured.1

This technique is used to facilitate the use of various types of fishing gear:

• Surrounding nets: Light and bait are sometimes used as lures to create the large, dense shoals necessary for the successful operation of purse seines and lampara nets.2
• Lift nets: Various lift-net fisheries, such as the basnig used in the Philippines or specialized Japanese gear for sauries, rely on luring lights to draw fish over submerged netting, which is then hauled to capture the school.3