School of Biological Sciences, University of Auckland, Auckland, New Zealand.
J Exp Biol. 2010 Nov 15;213(Pt 22):3832-42. doi: 10.1242/jeb.040790.
Blind Mexican cave fish (Astyanax fasciatus) are able to sense detailed information about objects by gliding alongside them and sensing changes in the flow field around their body using their lateral line sensory system. Hence the fish are able to build hydrodynamic images of their surroundings. This study measured the flow fields around blind cave fish using particle image velocimetry (PIV) as they swam parallel to a wall. Computational fluid dynamics models were also used to calculate the flow fields and the stimuli to the lateral line sensory system. Our results showed that characteristic changes in the form of the flow field occurred when the fish were within approximately 0.20 body lengths (BL) of a wall. The magnitude of these changes increased steadily as the distance between the fish and the wall was reduced. When the fish were within 0.02 BL of the wall there was a change in the form of the flow field owing to the merging of the boundary layers on the body of the fish and the wall. The stimuli to the lateral line appears to be sufficient for fish to detect walls when they are 0.10 BL away (the mean distance at which they normally swim from a wall), but insufficient for the fish to detect a wall when 0.25 BL away. This suggests that the nature of the flow fields surrounding the fish are such that hydrodynamic imaging can only be used by fish to detect surfaces at short range.
盲眼墨西哥洞穴鱼（Astyanax fasciatus）能够通过在物体旁边滑行并利用其侧线感觉系统感知身体周围流场的变化，从而感知物体的详细信息。因此，这些鱼能够构建周围环境的流体动力图像。本研究使用粒子图像测速法（PIV）测量了盲眼洞穴鱼在平行于墙壁游泳时周围的流场。还使用计算流体动力学模型来计算流场和侧线感觉系统的刺激。我们的结果表明，当鱼距离墙壁约 0.20 个体长（BL）内时，流场的形式会发生特征性变化。随着鱼与墙壁之间的距离减小，这些变化的幅度稳步增加。当鱼距离墙壁 0.02 BL 以内时，由于鱼体和墙壁上的边界层合并，流场的形式发生变化。侧线的刺激似乎足以让鱼在距离墙壁 0.10 BL（它们通常从墙壁游出的平均距离）时检测到墙壁，但当距离墙壁 0.25 BL 时不足以让鱼检测到墙壁。这表明鱼周围流场的性质使得流体动力成像只能用于鱼在短距离内检测表面。
