In Louisiana, speckled trout almost always spawn in groups numbering in dozens to thousands in deep, moving water, such as passes between barrier islands or natural and manmade channels in open water. Water depth in these locations is usually between 10 and 100 feet deep. Current seems to be necessary to keep the eggs from sinking to the bottom and suffocating.
Spawning always takes place between 6 p.m. and midnight. Males typically gather at the site an hour or two before sunset. There, they begin drumming — vibrating their tough swim bladder with surrounding muscles. The grunts, knocks and raps made by hundreds of males at one time sounds like a constant roar.
Drumming hits its peak around 8 or 9 p.m. and decreases sharply after 11 p.m. It is assumed that drumming activity attracts females to the site.
During spawning, the trout in the school mill constantly, with light side-to-side contact between the fish. Eggs and sperm are discharged into the water for random fertilization. The outgoing current in the channel or pass rapidly sweeps the eggs out to Gulf waters, where they float untended until they hatch.