Goldfish spectral sensitivity increase and shift with decreasing temperature

Goldfish spectral sensitivity is shown to be a function of temperature. Optic nerve responses (compound action potentials) to the onset (ON) and cessation (OFF) of a step stimulus were obtained at 10°C and 22°C. At 22°C the ON sensitivity peak at 460 nm with a secondary peak at 620 nm. The OFF sensitivity had a single peak at 620 nm. The peak sensitivities at 10°C were all shifted to longer wavelengths. At 10°C the ON sensitivity peaked at 500 nm and the secondary peak shifted to 660nm and was 300% higher than the 660 nm sensitivity at 22°C. The red OFF sensitivity shifted to 660 nm at 10°C was also 300% greater than the 22°C OFF sensitivity at 660 nm. The peak sensitivity shifts observed between the 22°C and 10°C data may be due to a change in concentration of the A 1 -vs. A 2 -based visual pigments: at 22°C the A 1 -based pigments predominate and at 10°C the A 2 -based pigments prevail. The increase in red sensitivity at 10°C for both the ON and OFF data could reflect the increased concentration of O 2 at the lower temperature. Only red sensitivity was affected by temperature. Both the shift in peak sensitivity across the spectrum at lower temperatures and the increase in red sensitivity are consistent with survival capabilities.