ABSTRACT
Bioluminescence of the sergestid shrimp, Sergia lucens was confirmed experimentally. To the unaided eye, light emission was oriented downward as a dim glow which originated from the ventral and lateral body surfaces. Image intensification revealed that this steady glow actually consisted of scintillating sources. Photophores first appear at 4.3 mm in carapace length (CL), and increase in number with growth. The arrangement is completed when the shrimp is sexually mature at 9.3 mm CL. The number of photophores of adults ranges between 158 and 169. Physiological mechanisms controlling the light emission are unknown. Gentle prodding of the body and electrical stimulation were ineffective, and there was very little response to serotonin treatment. The most effective stimuli were a strobe light flash and eyestalk crushing. Although the average emission measured from ovigerous females was approximately twice that from males, the differences in bioluminescence according to gender or reproductive condition were not statistically significant.
