McComb D Michelle, Frank Tamara M, Hueter Robert E, Kajiura Stephen M
Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 33431, USA.
Physiol Biochem Zool. 2010 Mar-Apr;83(2):299-307. doi: 10.1086/648394.
Visual temporal resolution and scotopic spectral sensitivity of three coastal shark species (bonnethead Sphyrna tiburo, scalloped hammerhead Sphyrna lewini, and blacknose shark Carcharhinus acronotus) were investigated by electroretinogram. Temporal resolution was quantified under photopic and scotopic conditions using response waveform dynamics and maximum critical flicker-fusion frequency (CFF). Photopic CFF(max) was significantly higher than scotopic CFF(max) in all species. The bonnethead had the shortest photoreceptor response latency time (23.5 ms) and the highest CFF(max) (31 Hz), suggesting that its eyes are adapted for a bright photic environment. In contrast, the blacknose had the longest response latency time (34.8 ms) and lowest CFF(max) (16 Hz), indicating its eyes are adapted for a dimmer environment or nocturnal lifestyle. Scotopic spectral sensitivity revealed maximum peaks (480 nm) in the bonnethead and blacknose sharks that correlated with environmental spectra measured during twilight, which is a biologically relevant period of heightened predation.
通过视网膜电图研究了三种沿海鲨鱼物种（窄头双髻鲨Sphyrna tiburo、无沟双髻鲨Sphyrna lewini和黑鼻鲨Carcharhinus acronotus）的视觉时间分辨率和暗视光谱敏感性。使用响应波形动态和最大临界闪烁融合频率（CFF）在明视和暗视条件下对时间分辨率进行了量化。在所有物种中，明视CFF（max）显著高于暗视CFF（max）。窄头双髻鲨的光感受器反应潜伏期最短（23.5毫秒），CFF（max）最高（31赫兹），这表明其眼睛适应明亮的光照环境。相比之下，黑鼻鲨的反应潜伏期最长（34.8毫秒），CFF（max）最低（16赫兹），表明其眼睛适应较暗的环境或夜行性生活方式。暗视光谱敏感性显示，窄头双髻鲨和黑鼻鲨的最大峰值（480纳米）与黄昏时测量的环境光谱相关，黄昏是捕食活动增强的生物学相关时期。
