Biology/Natural History: Since red light does not penetrate to the daytime depths of this prawn, the red parts of its body are effectively black. This species has organs of Pesta, which are bioluminescent, ventral to the red visceral mass. The organs of pesta have a shiny reflector to make the bioluminescence directional. As the animal moves through the water it turns the organs of pesta so that the bioluminescence is directed downward, thus effectively erasing its shadow. In situ studies in Monterey Bay showed that this species swims an average of 7.4 cm/s, or about 1.5 body lengths per second. Propulsion is exclusively by the pleopods, which beat at 4 Hz. The animal swims continuously, and remains above the oxygen minimum layer. It ascends near the surface at night and descends to deeper water during the day. The antennae respond to tactile stimuli and probably to vibrations in the water. This species matures in 1 or 2 years. Peak spawning is during the summer. May die after spawning. Feeds on large copepods and euphausiids. Predators include albacore, rockfish, sei and fin whales, and snipe eels.