Sastrugi sea ice than on multiyear ice. First-year ice is smoother than multiyear ice, which allows the wind to pass uniformly over the surface without topographic obstructions. Except during the melt season, snow is dry and light in climates cold enough for sea ice, allowing the snow to be easily blown and create sastrugi parallel to the wind direction. The locations of sastrugi are fixed by March in the northern hemisphere and may be linked to the formation of melt ponds. Melt ponds are more likely to form in the depressions between zastrugi on first-year ice. Sastrugi Sastrugi, or zastrugi, are
Surface wave detection by animals The wave-detection system of "A lineatus" and other surface feeding fish is tuned to match the waves that signal prey in their environment. "A lineatus" feeds on aquatic, semi-aquatic and terrestrial insects, often insects that have just touched the surface of the water or have fallen in and are struggling at the surface. Abiotic sources give off capillary waves of frequency 8–14 Hz, while biotic sources give off much higher frequencies, anywhere from 12–45 Hz and above. This correlates well with "A lineatus’" peak sensitivity at higher frequencies. Wave stimuli are classified into two types: the first is click stimuli