Form and function of the teleost lateral line revealed using three-dimensional imaging and computational fluid...

Area of Science:

• Ichthyology
• Hydrodynamics
• Sensory Biology

Background:

• Fishes possess a lateral line system to perceive water motion.
• Diversity in lateral line organ morphology (size, shape, mechanoreceptor distribution) exists across fish species.
• This diversity is hypothesized to relate to habitat-specific hydrodynamic conditions.

Purpose of the Study:

• To investigate the functional impact of lateral line canal morphology on hydrodynamic sensing.
• To simulate fluid dynamics around the cephalic lateral line in a model freshwater fish.
• To understand how variations in canal dimensions and epidermal features affect mechanoreceptor stimulation.

Main Methods:

• Acquisition of 3D imaging datasets of the cephalic lateral line in *Leuciscus idus*.
• Computational fluid dynamics (CFD) simulations to model water flow.
• Analysis of hydrodynamic phenomena around the head and within lateral line canals.

Main Results:

• Alterations in lateral line canal dimensions primarily affect absolute stimulation amplitudes.
• Canal dimensions show minimal impact on the relationship between bulk flow and high-frequency signals.
• Epidermal pits significantly reduce bulk flow stimulation and enhance the detection of higher-frequency signals relative to background flow.

Conclusions:

• Lateral line canal geometry plays a role in modulating the intensity of hydrodynamic stimuli.
• Epidermal pits act as a mechanism to fine-tune sensory input, potentially enhancing detection of specific flow patterns.
• These findings contribute to understanding the adaptive significance of lateral line diversity in relation to fish habitats.