Preliminary experiment with photoperiod to influence crawfish spawning

In the fall of 1977, crawfish that had been trepped in a pond during the summer were brought to the laboratory to observe spawning. In ambient light 34 out of 49 females spawned. In 1978 crawfish were trapped from the same pond and brought to the laboratory. Beginning 20 March, 18 crawfish were exposed to reduction of light duration by about 5 min per day. During June and July 14 females spawned and four did not spawn. Of 15 crawfish exposed to ambient light none spawned.