High-resolution measurements of swordfish skin surface roughness

Area of Science:

• Marine Biology
• Biophysics
• Surface Metrology

Background:

• The three-dimensional (3D) morphology of swordfish skin roughness is not well understood.
• Its physiological and hydrodynamic significance remains undetermined due to measurement challenges.

Purpose of the Study:

• To report and compare novel high-resolution 3D measurements of swordfish skin roughness.
• To characterize the spatial distribution and variability of skin roughness features.
• To provide data for developing synthetic models of swordfish skin.

Main Methods:

• Utilized a modular optical coherence tomography system for micron-scale resolution.
• Employed a gel-based stereo-profilometer for high-resolution 3D surface data acquisition.
• Derived topographical metrics using continuous and discrete approaches.

Main Results:

• Both techniques successfully provided 3D morphological data at micron-scale resolution.
• Identified spiny roughness elements, typically elongated streamwise, in groups up to six.
• Provided new insights into the spatial distribution and variability of these roughness features.

Conclusions:

• Advanced imaging techniques enable detailed characterization of complex biological surfaces like swordfish skin.
• The findings offer a foundation for understanding the role of skin roughness in swordfish physiology and hydrodynamics.
• The generated data can inform the creation of statistically representative models of swordfish skin texture.