The majority of eels enter a dormant phase during the chilly winter months, and fishing is typically ineffective at this time. Eels hibernate in the bottom muck throughout the winter. The duration of this stage in the eel’s life cycle can range from 5 years for males to 20 years or so for females.
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The eel’s rate of feeding and water temperature are positively correlated. As winter approaches, fewer eels are seen actively feeding at night due to low water temperatures. Eels hibernate in deep muck in backwaters, swampy areas, or drains as winter sets in, where they remain dormant until spring.
Hibernation has been fully established by capturing, observing, and recovery of the sleeping eels during marsh excavations over the winter in rivers and streams. Eels rescued using this technique are tightly curled and covered in a viscous slime. Physiological research, in particular studies of blood oxygen use, may be fascinating.
The entire population of eels never hibernates in the warmer lakes- or spring-controlled rivers and streams. Some eels can still be spotted actively moving and eating at night even in the middle of winter.
Do European eels hibernate?
European eels just like others go into the hibernation period of winters. For that purpose, they like to live in the swamps where there is muddy water and they can move through it. European eels can be found from the northern reaches of Russia and Finland down to the coasts of Morocco, Egypt, and even within the Black Sea.
This species is nocturnal and secretive, preferring to burrow into the mud and under stones during the day. At night, European eels emerge to feed on a variety of food sources, depending on their life stage. Their diet can include everything from other fish to mollusks and crustaceans, to even insects, worms, and carrion.
European eels are strong swimmers, but they have impressive climbing skills, too, allowing them to navigate obstacles such as dams in their upstream journeys. There are even reports of European eels leaving the water altogether and entering fields, where the species feasts on slugs and worms.
What time of year do eels migrate?
As previously mentioned, the initial transition takes place every year between October and December as 2-year-old elvers shift from the sea to fresh water. Millions of baby eels make up many of these “runs” in these waters. They are less usually seen when they are moving at night or during floods. When the baby eels locate suitable cover and feeding grounds in the lower sections of streams and rivers, their migration comes to an end. They stay here for the following four to five years.
Eels migrate upstream into this environment just after the seaward migration arrives. They are between 4-5 years old. It is now known that this upstream movement, which the author has managed to capture at specific locations on several New Zealand rivers, occurs annually at the end of January.
Mature female eels (10–14 years old) from upstream waters migrate to the sea in February and March to start their trek to the ocean’s reproductive grounds. These seaward migrations occur yearly as well. During the fall months, amazing accumulations of these mature migrants can be observed trying to reach the sea at Lake Onoke, Ellesmere, and Forsyth in which a bar of sand or gravel frequently forms at the outflows.
By mid-summer, 12–18% of upstream eel populations often start to mature and get ready for the downstream run (see full details of morphological and physiological changes later). Only 1.3 percent of the eels that would typically be regarded as migratory (based on gonad development) are still upstream by April.
Does an eel migrate?
Until they locate a home, they travel hundreds or thousands of miles upstream. The eels may travel over land and endure for long periods in dry or drying habitats during this excursion. The eels I captured at the family cabin used this skill to find their way there.
Do eels migrate to freshwater?
Eels have a freshwater growing stage, which is widely understood, however, this is not an obligate migration route; instead, it should be considered that they have a facultative catadromous with ocean dwellers as an ecophenotypic.