Effect of exposure of sturgeon roe to low-intensity laser radiation on the hardiness of juvenile sturgeon

We present data on the effect of polarized laser radiation in the near IR region of the spectrum with wavelength 808 nm on the resistance of juvenile sturgeon to oxygen deficiency in the habitat when the fertilized roe are briefly exposed to radiation in the organogenesis stage. The magnitude of the stimulating effect depends on the exposure time (t) and power density (P) of the radiation and also on its modulation frequency (F). For optimal irradiation parameters (cw mode, P = 2.9 mW/cm2, t = 60 sec), the hardiness of the juveniles increases by a factor of ∼1.5 compared with the control group. The maximum differences in the sensitivity of embryos to cw and pulsed radiation are observed for F = 1 Hz; as the modulation frequency increases up to F = 50 Hz, the magnitude of the photobiological effect approaches a level typical for cw exposure. We show that the duration of the dark period (pause time) between pulses is the critical parameter determining the dependence of the stimulating effect on the modulation frequency. We discuss questions concerning use of the indicated physical factor in the technology for raising sturgeon under industrial fish farming conditions.