CC, Dmitriy Konstantinov, http://ru.wikipedia.org
Most economically important in its order, most interesting, most well-known and most enigmatic, this eel and its life have been studied over 2300 years as to date, and it is by far not done. Adults inhabit European rivers – from Pechora to the rivers of the Black Sea. It lost commercial value in the Pskov-PeipsiLake after the dam of the Narva Hydro Power Plant was built in 1956, blocking its natural feeding migration route from the Gulf of Finland, and casting it rare.
Sometimes it grows up to 2 m in length, but on average to 50-150 cm (weighing 4-6 kg). The eel has fine and barely visible scales, usually lacking the silver shine; its back is dark green or brownish, sides are yellow, and belly yellowish or white. Its coloration is variable and depends on the age of the fish and nature of the water body. Its skin is slimy and slippery: a live eel is hard to hold. There are two commercial types of eels – pointy-headed and broad-headed. The former is more valuable, as its fat content reaches up to 27.5%, whereas it is only 12-19% in the latter. Usually sexually immature eels inhabit rivers, yet they do enter lakes and ponds.
When settling in, eels often use the smallest streams, sometimes finding their way into water supply systems. Cases were recorded when eels crawled their way from one water body into another over wet grass. In humid air and temperature of 24°С an eel can survive 36 hours out of water.
Eels are strictly nocturnal. They spend the light day in their shelter, most often dug up in ooze to 80 cm deep or to 1.5 m according to some data. At night – especially if it is cloudy and moonless – eels come out to hunt. Smaller species prey on larvae of aquatic insects, mollusks, worms and crustaceans. The diet of larger fish mainly consists of fish – small and commercially insignificant (perch, ruffe and roach). Despite the extreme voracity, eels are relatively slow to grow; yet, in favorable conditions surpluses of up to 500 gr per year were registered. The feeding season is in the warm part of the year – April to November. Eels do not forage in winter, hibernated deep in ooze.
/ * The photos at lake.peipsi.org are cross-posted from commons.wikimedia.org and are used for familiarization purposes only. No commercial use of the photos is allowed. For more information about to use the photos see the originals on commons.wikimedia.org. /
