Eels spawn far away in the Sargasso Sea, where their newly hatched larvae begin their migration by drifting with the ocean streams towards Europe. Eels arrive at Finnish shores around age six, at which point they have not only undergone a metamorphosis but have also travelled about 8,000 kilometres. The “yellow eels” stay at our shores for a few years until they reach sexual maturity and migrate to their spawning grounds in the Sargasso Sea. Before this, they undergo yet another metamorphosis and their colour changes to silver. At this point, the males are no more than half a meter long while the females are significantly larger. In addition to the migratory eels of the coastal waters, there are also eels in our inland waters mostly due to plantings. The eel is the longest living fish in Finland, the oldest eel found in Finland was seventy-two years old. The biggest eels at Maretarium are approximately a hundred and twenty centimetres long (that is approximately 47.24 inches), they weigh approximately three kilograms (that is 6.6 pounds) and they are born year 1976. Their age is known because they have been caught in lake Vesijärvi in Lahti where they were planted. Eel’s meat is very fatty and savoury, especially when it is smoked.
The eel is currently classified as a critically endangered species. In the sea area, recreational fishermen are not allowed to catch it at all, and in inland waters only in July.
In the summer of 2019, one of Maretarium’s female eels, born in 1976, matured the eggs spontaneously. This was the world’s first incident ever outside the Sargasso Sea. As a result of the incident, Maretarium is now involved in a research project related to eel reproduction funded by the European Union in 2023-2027. The project is led by the Wageningen University in the Netherlands. Researchers from 22 different countries are involved, including the Natural Resources Institute Finland and Maretarium from Finland.
