Sarvivälke

Sarvivälke is a Finnish term that translates to "horn sparkle" or "horned flash." It refers to a phenomenon observed in some species of fish, particularly those with prominent dorsal fins. When light strikes the scales or membranes of these fins at a specific angle, it can create a brief, iridescent shimmer or flash. This effect is often more pronounced in certain lighting conditions, such as during dawn or dusk, or when the fish are moving rapidly through the water.

The exact biological purpose of sarvivälke is not fully understood and may vary between species. However, several hypotheses exist. It is theorized that the flashing light could be used for communication within a school of fish, perhaps to signal danger or coordinate movements. Another possibility is that it serves as a form of camouflage, breaking up the outline of the fish and making it harder for predators to track. In some cases, the bright flashes might also be used to startle or disorient potential prey.

The intensity and color of the sarvivälke can differ depending on the fish's species, age, and the surrounding environment. Factors like water clarity and the angle of sunlight also play a significant role in how visible the phenomenon is. While it is a relatively subtle effect, it has been noted by anglers and marine biologists alike, contributing to the diverse visual displays found in the underwater world. The term itself highlights the delicate and fleeting nature of this visual characteristic.