We have all seen eel traps at mills
and the eels were often extra income for the miller and were caught in large
quantities, but have we wondered where the eels originate from?
European freshwater eels make an amazing migration
between the river and the sea, breeding
in the North Atlantic, the
Sargasso Sea, but living its adult life in fresh
water rivers some 3 to 4,000 miles away.
During spawning the female is believed
carry up to 10 million eggs. The eggs
hatch and these minute creatures
migrate across the
Atlantic towards the coast of the UK, drifting in the warm waters of the Gulf
Stream. This journey takes about two years and by the time they arrive they are
about 5 cm long.
When the larvae reach Europe they change
into the "glass eel" stage. These enter the freshwaters during the spring, with
the peak of the migration taking place on the increasing spring tides in April
They gather at the large
river mouths, such as the Severn Estuary and then head upriver in search of a
new freshwater habitat. Their movement
upstream is mainly triggered when the
river water temperature
reaches 10° to 12°C, migrating upstream during the flood tide and
changing colour into the familiar dark elvers .
Eels live on or near the
bottom of rivers and lakes, migrating slowly upstream.
During this period they are commonly referred to as yellow or brown eels
due to their colour, feeding mainly on invertebrates, although larger
individuals may also eat other fish.
Capable of surviving for periods of time out of water, eels can cross land and
damp meadows in their search for water systems and lakes.
Male eels stay in
fresh water for between 7 and 12 years, maturing at a length of about 36cm while
the females stay between 9 and 16 years, maturing at the slightly larger size of
they are mature enough to breed.
Mature eels prefer to move
seawards when it is dark and large migrations are known to occur on wet, stormy
autumn nights especially when the half-moon is on the wane.
They change to a
(known as "silver eels") and start their migration downstream to the sea.
reaching the sea they stop feeding and so have to rely on stored energy alone.
Their body undergoes dramatic changes: the eyes start to enlarge in size, the
eye pigments change for optimal vision in dim, blue, clear, ocean light, and the
sides of their bodies turn silvery, to create a counter-shading pattern to make
them difficult to see by predators during their long open ocean migration.
This migration will take almost six months before they reach their
breeding grounds, spawn and die.
Eels are now an endangered species as their numbers have decreased alarmingly
during the past 20
years. In fact, eel-ladders as well as
fish-ladders are now being built in Somerset.
Freshwater eels are eaten
a traditional east London food is jellied
although their demand has significantly declined since World War II.
Fisherman consumed elvers as a cheap dish, but environmental changes have
reduced eel populations. They are now considered a delicacy and are priced at up
to £700 per kg in the U.K.
In Holland smoked eels are the delicacy.