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Summary
The North Sea houting is one of the most endangered spe-
cies of fish in Europe. It was once common throughout the
Wadden Sea, but destruction of its breeding areas in water-
courses, fragmentation of watercourses, pollution and over-
fishing have led to its near extinction. There was only one
population left in the river Vidåen in Southern Jutland when
the seriousness of the situation dawned on the responsible
authorities. Much has been done to bring the houting back
again. A total of 1.7 million fry was released in southwest
Jutland watercourses in the period 1987-1992, and attempts
were made to improve the houting’s living conditions. The
work failed, however, to have the hoped-for effect, and in
2005, Denmark’s second largest nature restoration project
was initiated in order to save the species.
The houting’s life and biology are closely dependent
on the conditions in the Wadden Sea. The houting spawns
in the watercourses, but grows to maturity in the Wadden
Sea. Its ability to migrate between fresh water and salt water
makes the houting unique among other members of the sal-
monid genus
Coregonus
. The fry spend the first few months
of their life in the watercourses, where they are particu-
larly dependent on areas of relatively static water. Flooded
marshes and lakes are therefore important habitats for the
fry until, at a length of 3-6 cm., they migrate into the Wad-
den Sea. The adult houting is not a good swimmer and it
cannot pass even minor obstacles in the watercourses. It is
therefore completely dependent on free passage in the wa-
tercourse in order to reach its breeding grounds.
Following release and watercourse restoration projects,
there are now houtings in several watercourses in southwest
Jutland. Populations are, however still small, and they suf-
fer from poor breeding success, which means that there is
no notable growth in the populations. The river Vidåen is
the only habitat to regularly produce surviving young. The
houting thus continues to be extremely vulnerable and to
require protection and help in the form of reestablishment
of its habitats.
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