Reproduction as backbreaking work
Once in their life, eels put everything they have into reproduction - which literally gets to their bones. With this strategy, they were well adapted to their migration to the spawning grounds in the ocean for millions of years. But now humans are endangering the evolutionary recipe for success.
Opinions differ when it comes to eel as an edible fish: smoked and cut into decorative morsels, it is a juicy delicacy for some, while others prefer to avoid the calorie bomb dripping with fat. Of course, the high fat content of the eel is not just a whim of nature, but the perfect adaptation to its unique way of life as a globetrotter. As the Danish biologist Johannes Schmidt (1877-1933) recognized about 100 years ago, the European eel (Anguilla anguilla) spawns in a tropical region of the Atlantic Ocean known as the Sargasso Sea. This is where the larvae hatch, glass-like, transparent, willow-leaf-shaped tiny creatures that make their way over 5,000 kilometers to their parents' home rivers in Europe. Years later, the sexually mature animals return – sometimes against the current – to the Sargasso Sea to spawn.
Probably each eel masters this hardship only once and dies of exhaustion after spawning…