kõrvalesta

Kõrvalesta is a term of Estonian origin that translates to "side fin" or "pectoral fin" in English. It refers to the paired fins located on either side of a fish's body, just behind the gill covers. These fins are homologous to the forelimbs of terrestrial vertebrates.

The primary functions of the kõrvalesta are varied and crucial for a fish's survival and mobility. They are essential for steering, braking, and providing lift, allowing the fish to control its movement in three dimensions. Many fish also use their kõrvalesta for slow swimming, hovering, and maneuvering through complex environments like coral reefs or aquatic vegetation. In some species, the kõrvalesta can be modified for specialized purposes. For instance, in certain bottom-dwelling fish, they may be enlarged and adapted for walking or digging. Flying fish use their enlarged pectoral fins to glide through the air after leaping from the water.

The shape, size, and structure of the kõrvalesta can vary significantly between different fish species, reflecting adaptations to their specific ecological niches and behaviors. These variations can include differences in fin ray structure, musculature, and membrane development. Studying the kõrvalesta provides valuable insights into the evolutionary history and functional morphology of fish.